Manufacturing of highly porous carbon particles from metalorganic salt compositions for lithium-ion batteries

Abstract

A method of making porous carbon particles is disclosed. The method includes: (A1) making a solution including a magnesium organic salt composition; (A2) precipitating particles of the magnesium organic salt composition from the solution; (A3) pyrolyzing the particles of the magnesium organic salt composition to form precursor composite particles including carbon and at least one magnesium compound; and (A4) selectively removing the magnesium compound(s) from the precursor composite particles to convert the precursor composite particles to the porous carbon particles. In some implementations, the at least one magnesium compound includes MgO. A related method of forming silicon-carbon composite particles is also disclosed. Porous carbon particles, silicon-carbon composite particles, anode electrodes, lithium-ion rechargeable batteries, and other related processes and components are also disclosed.

Description

MANUFACTURING OF HIGHUY POROUS CARBON PARTICUES FROM METAUORGANIC SALT COMPOSITIONS FOR LITHIUM- ION BATTERIESCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present Application for Patent claims the benefit of U.S. Provisional Application No. 63 / 670,058, entitled “MANUFACTURING OF HIGHLY POROUS CARBON PARTICLES FROM METALORGANIC SALT COMPOSITIONS FOR LITHIUM-ION BATTERIES,” filed July 11, 2024, and U.S. Provisional Application No. 63 / 770,483, entitled “MANUFACTURING OF HIGHLY POROUS CARBON PARTICLES FROM METALORGANIC SALT COMPOSITIONS FOR LITHIUM-ION BATTERIES,” filed March 12, 2025, each of which is assigned to the assignees hereof, and each of which is expressly incorporated herein by reference in its entirety.GOVERNMENT LICENSE RIGHTS

[0002] This invention was made with government support under contract number DE-AR0001452 awarded by the Advanced Research Projects Agency -Energy (ARPA-E) within the United States Department of Energy (DOE). The government has certain rights in the invention.BACKGROUND

[0003] Field

[0004] Aspects of the present disclosure relate generally to energy storage devices, and more particularly to battery technology and the like.

[0005] Background

[0006] Owing in part to their relatively high energy densities, relatively high specific energy, light weight, and potential for long lifetimes, advanced rechargeable batteries are desirable for a wide range of consumer electronics, electric vehicles, grid storage and other important applications. However, despite the increasing commercial prevalence of batteries, further development of these batteries is needed, particularly for applications in low- or zero-emission, hybrid-electric or fully electric vehicles, consumer electronics, wearable devices, energy-efficient cargo ships and locomotives, drones, aerospace applications, and power grids. Further improvements are desired for various rechargeablebatteries, such as rechargeable Li and Li-ion batteries, Na and Na-ion batteries, K and K- ion batteries, and dual ion batteries, to name a few.

[0007] In certain types of Li metal and Li-ion rechargeable batteries, charge storing anodes may comprise silicon (Si)-comprising anode particles with gravimetric capacities in the range from about 800 mAh / g to about 3000 mAh / g (per mass of Si-comprising anode particles in a Li-free state). A subset of such anodes includes anodes with the electrode layer exhibiting capacity in the range from about 400 mAh / g to about 2800 mAh / g (per mass of the electrode layer, not counting the mass of the current collector, in a Li-free state). Such a class of charge-storing anodes offers great potential for increasing gravimetric and volumetric energy of rechargeable batteries.

[0008] In certain types of rechargeable batteries, charge storing anode active materials may be produced as high-capacity (nano)composite powders, which exhibit moderately high volume changes (e.g., about 8-250 vol. %) during the first chargedischarge cycle and moderate volume changes (e.g., about 5-60 vol. %) during the subsequent charge-discharge cycles. A subset of such charge-storing anode particles includes anode particles with a volume-average size (e.g., diameter or thickness) in the range of about 0.2 to about 40 microns (micrometers, or pm), as measured using laser particle size distribution analysis (LPSA), laser image analysis, electron microscopy, optical microscopy or other suitable techniques. Such a class of charge-storing particles offers great promises for scalable manufacturing and achieving high cell-level energy density and other performance characteristics.

[0009] The transportation sector is a major contributor to greenhouse gas (GHG) emissions (-30%), which play a major part in climate change. Due to the current performance limitations and the high price of Li-ion batteries (LIB) for electric vehicles (EVs), the electrification of transportation is slowing down. Consumers cite limitations on range, charge time, charging infrastructure, and cost as the top 4 reasons for not adopting EVs. Therefore, major steps must be undertaken to improve LIB performance and reduce costs to accelerate electrification and achieve the 2050 net-zero emission goal. Indeed, EVs offer -70% life cycle GHG emissions reduction compared to internal combustion engine (ICE) vehicles in the U.S. Traditional LIB anodes are graphite (Gr)- based, but these are neither sustainable nor environmentally friendly due to the mining of natural Gr and extremely high process temperatures (-3000 °C) and, thus, high energy consumption needed for synthetic Gr production. The most promising and sustainablepathway to improve EV performance and make EVs more desirable to mass market customers is to replace Gr with silicon-carbon (Si-C) (nano)composite particles, which offer 20-40% higher energy density and dramatically reduced charging time (< 10 min). Some conventional processes for synthesis of high-performing Si-C (nano)composite particles involve the formation of nanoporous carbon scaffolding material, partially filling the pores with Si via a vapor infiltration route and sealing such pores to produce internal pores that accommodate Si volume changes during cycling and allow stable LIB performance for up to 2,000 cycles to be attained.

[0010] One major downside of this previously developed technology are the high monetary and environmental costs involved in forming nanoporous carbon scaffolds with sufficiently high pore volume. The conventional porous carbon synthesis processes involve carbonization and activation of natural organic carbon precursors (mostly wastewood or coconut shells), which are slow and inefficient (in many cases only -2-5% of the carbon atoms survive; the rest transform to CO2). Furthermore, the shape, uniformity, and properties of the attained Si-C are hard to control and the attainable performance in LIB becomes limited.

[0011] In one commercialization example, a drop-in replacement for Gr anode powder is Si-C composite anode powder. In a further example, when manufactured in LIBs with pure Si-C (nano)composite or blended Si-C (nano)composite / Gr anodes, a current synthesis technique for Si-C (nano)composite anode powder may reduce carbon dioxide emissions per unit electrical energy (kgCCh eq. / kWh) compared to incumbent synthetic Gr by an estimated -5-10%. In some designs, the current Si-C (nano)composite synthesis technique satisfies some or all of the need(s) of EV customers but relies on high- intensity GHG emissions due to low carbon scaffold throughput. Indeed, in some designs, the high porosity needed for high-performance Si-C (nano)composite relies on -80-98% losses of C atoms during carbonization and classic activation of carbon feedstock, producing CO2 which needs to be captured and recycled. Accordingly, what is desired is a new technology that is based on a transformational use of carbon as a sustainable building block for batteries (e.g., in the form of high-throughput Si-C composites generated from environmentally friendly biogenic carbon feedstock and recyclable porogen (pore-forming material) that generates the necessary high pore volumes for high- energy Si-C anode cells with little activation or without any activation). In some designs, such a sustainable, ultra-high performance, high-throughput Si-C composite synthesispathway to reduce CO2 emissions to below 50kg CO2 eq. / kWh at the LIB pack level may be a development and deployment objective.

[0012] Accordingly, there remains a need for improved batteries, components, and other related materials and manufacturing processes.SUMMARY

[0013] The following presents a simplified summary relating to one or more aspects disclosed herein. Thus, the following summary should not be considered an extensive overview relating to all contemplated aspects, nor should the following summary be considered to identify key or critical elements relating to all contemplated aspects or to delineate the scope associated with any particular aspect. Accordingly, the following summary has the sole purpose to present certain concepts relating to one or more aspects relating to the mechanisms disclosed herein in a simplified form to precede the detailed description presented below.

[0014] In an aspect, a method of making porous carbon particles includes (Al) making a solution comprising a magnesium organic salt composition; (A2) precipitating particles of the magnesium organic salt composition from the solution; (A3) pyrolyzing the particles of the magnesium organic salt composition to form precursor composite particles comprising carbon and at least one magnesium compound; and (A4) selectively removing the at least one magnesium compound from the precursor composite particles to convert the precursor composite particles to the porous carbon particles, wherein: the at least one magnesium compound comprises MgO.

[0015] In an aspect, a method of making silicon-carbon composite particles includes (Cl) making primary magnesium organic salt composition particles; (C2) forming the primary magnesium organic salt composition particles into granules or pellets; (C3) pyrolyzing the granules or pellets to form granulated precursor composite particles comprising carbon and at least one magnesium compound, wherein: the at least one magnesium compound comprises MgO; (C4) selectively removing the at least one magnesium compound from the granulated precursor composite particles to convert the granulated precursor composite particles to porous carbon granules; (C5) forming a silicon material on and / or in the porous carbon granules to form silicon-carbon composite granules; (C6) forming a protective material on and / or in the silicon-carbon composite granules, wherein: the protective material comprises carbon and / or an oxide; and (C7)comminuting the silicon-carbon composite granules to obtain the silicon-carbon composite particles with a D50 from about 1 pm to about 20 pm.

[0016] Other objects and advantages associated with the aspects disclosed herein will be apparent to those skilled in the art based on the accompanying drawings and detailed description.BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings are presented to aid in the description of embodiments of the disclosure and are provided solely for illustration of the embodiments and not limitation thereof. Unless otherwise stated or implied by context, different hatchings, shadings, and / or fill patterns in the drawings are meant only to draw contrast between different components, elements, features, etc., and are not meant to convey the use of particular materials, colors, or other properties that may be defined outside of the present disclosure for the specific pattern employed.

[0018] FIG. 1 illustrates an example Li-ion battery in which the components, materials, processes, and / or other techniques described herein may be implemented.

[0019] FIG. 2 is a flow diagram of a process of making a Li-ion rechargeable battery cell in accordance with certain embodiments.

[0020] FIG. 3 is a flow diagram of a process of making silicon-carbon (nano)composite particles from porous carbon particles.

[0021] FIG. 4 is a schematic illustration of an example process of making porous carbon particles.

[0022] FIGS. 5 A and 5B illustrate example magnesium organic salts.

[0023] FIGS. 6 A and 6B are flow diagrams of example processes of making porous carbon particles.

[0024] FIGS. 7A, 7B, 7C, and 7D are flow diagrams of example processes of preparing a solution of a magnesium organic salt composition.

[0025] FIGS. 8 A and 8B show scanning electron microscope (SEM) images of example porous carbon particles.

[0026] FIG. 9 shows a graphical plot of the dependence of a total pore volume (TPV) of porous carbon particles (i.e., after selective removal of MgO) on the mass fraction of MgO in the precursor composite particles.

[0027] FIG. 10A shows a graphical plot of the dependence of a total pore volume (TPV) of porous carbon particles (i.e., after selective removal of MgO) on the value of parameter x characterizing the fraction of the acetate ligand in hybrid magnesium salts of the form Mg3Cit2-xAc3x.

[0028] FIG. 10B (Table 1) shows (1) the molecular mass of the citrate ligand Cit2-X, (2) the molecular mass of the acetate ligand Ac3X, (3) the total mass of the hybrid magnesium salt of the form Mg3Cit2-xAc3X, and (4) the mass fraction of the acetate ligand in a sum of the masses of the acetate ligand Ac3Xand the citrate ligand Cit2-X„ for values of x ranging between 0.0 and 1.0.

[0029] FIG. 11 shows a graphical plot of the dependence of the gravimetric charge capacity (expressed as a fraction of the cycling-start charge capacity) on cycle number, of lithium-ion battery test cells in which the anodes comprise silicon-carbon composite particles made from porous carbon particles as described herein.

[0030] FIG. 12A is a schematic illustration of a chemical reaction in the etching of MgO by citric acid.

[0031] FIG. 12B is a schematic illustration of chemical reactions in the etching of MgO by sulfuric acid.

[0032] FIG. 12C is a schematic illustration of chemical reactions in the etching of MgO by carbonic acid.

[0033] FIG. 13 (Table 2) shows (1) the BET specific surface areas and (2) the total pore volumes (TP Vs) of samples of porous carbon particles formed from a common sample of precursor composite particles (MgO-C composite). Each sample of porous carbon particles was formed by etching with a respective etchant (carbonic acid, sulfuric acid, hydrochloric acid, citric acid, acetic acid).

[0034] FIG. 14 illustrates an example of a suitable process for the formation of Si-C particles with the desired particle size distribution according to some of the embodiments of the present disclosure.

[0035] FIG. 15 illustrates an example of granules produced from Mg citrate particles by an extrusion process.

[0036] FIG. 16 illustrates examples of uniform tablet-shaped (cylindrical) granules produced from Mg citrate particles mixed with a binder (70 wt. % Mg citrate and 30 wt. % binder (20 wt. % poly(lauryl methacrylate) (PLMA) and 10 wt. % polyethylene glycol (PEG)) using a tablet press.

[0037] FIG. 17 illustrates examples of irregularly-shaped granules produced from Mg citrate particles mixed with a binder (70 wt. % Mg citrate and 30 wt. % binder (20 wt. % poly(lauryl methacrylate) (PLMA) and lOwt. % polyethylene glycol (PEG)) using a tablet press followed by breaking and sieving to make 2-3.5 mm granules.

[0038] FIG. 18 illustrates an example SEM image (1801) of primary porous C-MgO composite particles produced by pyrolysis of Mg citrate particles and an example SEM image (1802) of the cross-section of pyrolyzed Mg citrate particles after MgO dissolution and removal (cross-section of porous carbon particles with less than 1 wt. % of MgO remaining).

[0039] FIG. 19 illustrates an example of the particle size distribution of porous carbon particles obtained by comminution of porous carbon granules using different parameter settings on a laboratory scale jet mill.

[0040] FIG. 20 (Table 3) illustrates some of the binders that may be advantageously used for the formation of granules.

[0041] FIGS. 21-23 illustrate the carbon yield in the range from about 5 to about 38 wt. % attained by heating different candidate binder materials in an inert environment.DETAILED DESCRIPTION

[0042] Aspects of the present invention are disclosed in the following description and related drawings directed to specific embodiments of the invention. The term “embodiments of the invention” does not require that all embodiments of the invention include the discussed feature, advantage, process, or mode of operation, and alternate embodiments may be devised without departing from the scope of the invention. Additionally, well-known elements of the invention may not be described in detail or may be omitted so as not to obscure other, more relevant details.

[0043] Aspects of the present disclosure provide for processes of making advanced carbon-containing composite particles for use in electrodes (e.g., anode electrodes or cathode electrodes) of Li-ion or Na-ion or K-ion rechargeable batteries, among other types of batteries, electrochemical capacitors and hybrid electrochemical energy storage devices.

[0044] Any numerical range described herein with respect to any embodiment of the present invention is intended not only to define the upper and lower bounds of the associated numerical range, but also as an implicit disclosure of each discrete value within that range in units or increments that are consistent with the level of precision by which the upper and lower bounds are characterized. For example, a numerical distance range from 7 nm to 20 nm (i.e., a level of precision in units or increments of ones) encompasses (in nm) a set of [7, 8, 9, 10, ..., 19, 20], as if the intervening numbers 8 through 19 in units or increments of ones were expressly disclosed. In another example, a temperature range from about - 120 °C to about - 60 °C encompasses (in °C) a set of temperature ranges from about - 120 °C to about - 119 °C, from about - 119 °C to about - 118 °C, .... from about - 61 °C to about - 60 °C, as if the intervening numbers (in °C) between - 120 °C and - 60 °C in incremental ranges were expressly disclosed. In yet another example, a numerical percentage range from 30.92% to 47.44% (i.e., a level of precision in units or increments of hundredths) encompasses (in %) a set of [30.92, 30.93, 30.94, ..., 47.43, 47.44], as if the intervening numbers between 30.92 and 47.44 in units or increments of hundredths were expressly disclosed. Hence, any of the intervening numbers encompassed by any disclosed numerical range are intended to be interpreted as if those intervening numbers had been disclosed expressly, and any such intervening number may thereby constitute its own upper and / or lower bound of a sub-range that falls inside of the broader range. Each sub-range (e.g., each range that includes at least oneintervening number from the broader range as an upper and / or lower bound) is thereby intended to be interpreted as being implicitly disclosed by virtue of the express disclosure of the broader range. In yet another example, a numerical range with upper and lower bounds defined at different levels of precision shall be interpreted in increments corresponding to the bound with the higher level of precision. For example, a numerical percentage range from 30.92% to 47.4% (i.e., levels of precision in units or increments of hundredths and tenths, respectively) encompasses (in %) a set of [30.92, 30.93, 30.94, ..., 47.39, 47.40], as if 47.4% (tenths) was recited as 47.40% (hundredths) and as if the intervening numbers between 30.92 and 47.40 in units or increments of hundredths were expressly disclosed.

[0045] It will be appreciated that the level of precision of any particular measurement, threshold or other inexact parameter may vary based on various factors such as measurement instrumentation, environmental conditions, and so on. Below, reference to such measurements or thresholds may thereby be interpreted as a respective value assuming a pseudo-exact level of precision (e.g., a threshold of 80% comprises 80.0000...%). Alternatively, reference to such measurements or thresholds may be described via a qualifier that captures pseudo-exact value(s) plus a range that extends above and / or below the pseudo-exact value(s). For example, the above-noted threshold of 80% may be interpretedwhich encompasses “exactly” 80% (e.g., 80.0000...%) plus some range around 80%. In some designs, the range encompassed around a measurement or threshold via the “about”, “approximately”, “around” orqualifier may encompass the level of precision for which the respective measurement or threshold is capable of being measured by the most accurate commercially available instrumentation as of the priority date of the subject application.

[0046] In the following description, various material properties are described so as to characterize materials (e.g., binders, molecules, particles, powders, slurries, electrodes, separators, electrolytes, battery cells, etc.) in various states. Note that one of ordinary skills in the art is generally capable of selecting (and is herein assumed to select) the most appropriate measurement technique for any particular measurement. Moreover, in some cases, the most appropriate measurement technique may include a combination of techniques. While the following Table characterizes various measurement type options for particular material types and particular material properties, certain embodiments ofthe disclosure may be more specifically characterized in context with a specific measurement technique and / or specific commercially available instrumentation, if warranted. Note that while the Table below characterizes measurements with respect to active material particles, similar measurements may also be made with respect to other particle types, such as precursor particles (e.g., carbon particles, etc.). Hence, unless otherwise indicated, the following Table provides examples of how such material properties may be readily measured by one of ordinary skill in the art using commercially available instrumentation:

[0047] Table of Techniques and Instrumentation for Material Property Measurements

[0048] In certain aspects, the disclosure relates to batteries. While the description below may describe certain examples in the context of Li metal and Li-ion batteries (for brevity and convenience, and because of the current popularity of Li technology), it will be appreciated that various aspects may be applicable to other rechargeable and primary batteries (such as Na and Na-ion, Mg and Mg-ion, K and K-ion, Ca and Ca-ion, and other metal and metal-ion batteries, dual ion batteries, alkaline or alkaline ion batteries, flow batteries, etc.) as well as electrochemical capacitors and hybrid energy storage devices.

[0049] While the description below may describe certain examples in the context of composites comprising specific (e.g., alloying-type or conversion-type) active anode materials (such as Si, among others) or specific (e.g., intercalation-type or conversiontype) active cathode materials, it will be appreciated that various aspects may be applicable to many other types and chemistries of conversion-type anode and cathode active materials, intercalation-type anode and cathode active materials, pseudocap acitive anode and cathode active materials, and materials that may exhibit mixed electrochemical energy storage mechanisms.

[0050] While the description below may also describe certain examples of the material formulations in a Li-free state (for example, as in silicon-comprising nanocomposite anodes or metal fluoride cathodes or sulfur cathodes, etc.), it will be appreciated that various aspects may be applicable to Li-comprising electrodes and active materials (for example, partially or fully lithiated Si-comprising anodes or partially or fully lithiated Si-comprising anode particles, partially or fully lithiated metal fluoride comprising cathodes (such as a mixture of LiF and metals such as Cu, Fe, Ni, Bi, Zr, Ti, Mg, Nb, and various other metals and metal alloys and mixtures of such and / or other metals, etc.) or partially or fully lithiated metal halide comprising cathode particles, partially or fully lithiated chalcogenides (such as Li2S, Li2S / metal mixtures, Li2Se, Li2Se / metal mixtures, Li2S-Li2Se mixtures, various other compositions comprising lithiated chalcogenides etc.), partially or fully lithiated metal oxides (such as Li2O, Li2O / metal mixtures, etc.), partially or fully lithiated intercalation-type cathode materials, partially or fully lithiated carbons, among others). In some designs, various material properties (e.g., at particle level, at inter-particle level, at electrode level, etc.) may change based on whether active material parti cle(s) are in a Li-free state, a partially lithiated state, or a fully lithiated state. Such Li-dependent material properties may include particle pore volume, electrode pore volume, and so on. Unless stated or implied otherwise, referenceto such Li-dependent anode material properties (e.g., at particle level, at inter-particle level, at electrode level, etc.) may be assumed to be provided as if the active material particles are in the Li-free state. Further, some examples below are characterized at the electrode level (e.g., as opposed to particle level or interparticle level or cell level, etc.). Below, unless stated or implied otherwise, reference to such electrode level properties (e.g., electrode porosity or areal capacity loading or gravimetric / volumetric capacity, etc.) may be assumed to refer to the electrode components (e.g., active material particles, binder, conductive additives, etc.), excluding the current collector.

[0051] While the description below may describe certain examples in the context of some specific alloying-type, conversion-type and intercalation-type chemistries for anode active materials and conversion-type and intercalation-type chemistries for cathode active materials for Li-ion batteries (such as silicon-comprising anodes or metal fluoride- comprising or lithium sulfide-comprising cathodes), it will be appreciated that various aspects may be applicable to other chemistries for Li-ion batteries (other conversion-type and alloying-type electrodes as well as various intercalation-type anodes and cathodes) as well as to other battery chemistries. In the case of metal-ion batteries (such as Li-ion batteries), examples of other suitable conversion-type electrodes include, but are not limited to, metal fluorides, metal oxyfluorides, metal chlorides, metal iodides, metal bromides, sulfur, metal sulfides (including, but not limited to lithium sulfide), selenium, metal selenide (including, but not limited to lithium sulfide), metal oxides, metal nitrides, metal phosphides, metal hydrides, their various mixtures, composites (including nanocomposites) and alloys and others.

[0052] During battery (such as a Li-ion battery) operation, conversion materials change (convert) from one crystal structure to another (hence the name “conversion”- type), where a material structure and composition may chemically and structurally change to one or multiple structures. This process is also accompanied by breaking chemical bonds and forming new ones. During battery (e.g., Li-ion battery) operation, Li ions are inserted into alloying-type materials forming lithium alloys (hence the name “alloying”- type). Sometimes, “alloying”-type electrode materials are considered to be a subclass of “conversion”-type electrode materials.

[0053] While the description below may describe certain examples in the context of Si-C composite (e.g., nanocomposite) anode active materials (e.g., nanocomposite particles which comprise silicon (Si) and carbon (C) and may comprise other elements,such as nitrogen (N), phosphorus (P), boron (B), oxygen (O), hydrogen (H), sulfur (S), fluorine (F), to name a few and where a total mass of the Si and the C atoms may contribute from about 75 wt. % to about 100 wt. % of the total mass of the composite particles), it will be appreciated that various aspects may be applicable to other types of the high-capacity silicon-comprising anode active materials (including but not limited to, for example, various silicon-comprising or silicon oxide-comprising or silicon nitridecomprising or silicon oxy-nitride-comprising or silicon phosphide-comprising particles or particles comprising a mixture or alloy or other combinations of such active materials, various other types of Si-comprising composites including, but not limited to core-shell or hierarchical or nanocomposite particles, etc.).

[0054] An aspect is directed to a battery anode and / or a battery anode precursor composition comprising a population of Si-comprising particles (e.g., nanocomposite particles, among others), in which some or all of the Si-comprising particles comprise silicon (Si) and carbon (C) elements and may comprise other elements, such as nitrogen (N), phosphorus (P), boron (B), oxygen (O), hydrogen (H), sulfur (S), fluorine (F), to name a few. In some embodiments, the total mass of the Si and the C (on average) in the Si-comprising particles may contribute from about 75 wt. % to about 100 wt. % of the total mass of the Si-comprising particles. Such composite particles are sometimes referred to herein as Si-C composites (or nanocomposites, if Si and / or C are nanostructures, for example).

[0055] In some embodiments, the total mass of O may contribute (on average) from about 0 wt. % to about 10 wt. % of the total mass of the Si-comprising particles (in some designs, from about 0 wt. % to about 1 wt. %; in other designs, from about 1 wt. % to about 2.5 wt. %; in other designs, from about 2.5 wt. % to about 5 wt. %; in other designs, from about 5 wt. % to about 10 wt. %). In some embodiments, the total mass of O may contribute (on average) to less than about 5 wt. % of the total mass of the Si-comprising particles. In some embodiments, the total mass of N may contribute (on average) from about 0 wt. % to about 10 wt. % of the total mass of the Si-comprising particles (in some designs, from about 0 wt. % to about 0.1 wt. %; in other designs, from about 0.1 wt. % to about 2 wt. %; in other designs, from about 2 wt. % to about 5 wt. %; in yet other designs, from about 5 wt. % to about 10 wt. %). In some embodiments, the total mass of P may contribute (on average) from about 0 wt. % to about 10 wt. % of the total mass of the Si- comprising particles (in some designs, from about 0 wt. % to about 0.1 wt. %; in otherdesigns, from about 0.1 wt. % to about 1 wt. %; in other designs, from about 1 wt. % to about 5 wt. %; in yet other designs, from about 5 wt. % to about 10 wt. %). In some embodiments, the total mass of B may contribute (on average) from about 0 wt. % to about 5 wt. % of the total mass of the Si-comprising particles (in some designs, from about 0 wt. % to about 0.1 wt. %; in other designs, from about 0.1 wt. % to about 2.5 wt. %; in yet other designs, from about 2.5 wt. % to about 5 wt. %). In some embodiments, the total mass of H may contribute (on average) from about 0 wt. % to about 2 wt. % of the total mass of the Si-comprising particles (in some designs, from about 0 wt. % to about 0.5 wt. %; in other designs, from about 0.5 wt. % to about 1 wt. %; in yet other designs, from about 1 wt. % to about 2 wt. %). In some embodiments, the total mass of S may contribute (on average) from about 0 wt. % to about 2.5 wt. % of the total mass of the Si-comprising particles (in some designs, from about 0 wt. % to about 0.1 wt. %; in other designs, from about 0.1 wt. % to about 0.5 wt. %; in yet other designs, from about 0.5 wt. % to about 2.5 wt. %). In some embodiments, the total mass of F may contribute (on average) from about 0 wt. % to about 2.5 wt. % of the total mass of the Si-comprising particles (in some designs, from about 0 wt. % to about 0.1 wt. %; in other designs, from about 0.1 wt. % to about 0.5 wt. %; in yet other designs, from about 0.5 wt. % to about 2.5 wt. %).

[0056] In some embodiments, a total atomic fraction of the Si and the C may contribute from about 75 at. % or about 80 at. % to about 100 at. % of the overall composite particles. Such composite particles are sometimes referred to herein as Si-C composites. In some embodiments, such composite particles comprise nano-sized or nanostructured elements (e.g., nano-sized or nanostructured Si, Si nanoparticles, nanoporous Si nanoparticles, nano-sized, nanoporous or nanostructured C, or both), which may be referred to as nanocomposite particles. In some implementations, the Si or Si-comprising active material present in such nanocomposites may be in the form of nanoparticles. In some implementations, the mass-average size of Si or Si-comprising material nanoparticles (e.g., silicon nanoparticles or nanocrystals) may range from about 1 nm to about 200 nm (in some designs, from about 1.0 nm to about 10.0 nm; in other designs, from about 10.0 nm to about 30.0 nm; in yet other designs, from about 30.0 nm to about 100.0 nm; in yet other designs, from about 100.0 nm to about 200.0 nm), as measured using image analysis of electron microscopy (e.g., transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM), scanningelectron microscopy (SEM)), X-ray microscopy, X-ray diffraction, neutron scattering and / or other suitable techniques. In some designs, Si or Si-comprising material nanoparticles (e.g., silicon nanoparticles) may be doped (e.g., in some designs with Group V or Group III elements, such as N, P, B, etc.; or, in other designs, with Group IV elements, such as C, etc.; or their various combinations). The degree of doping may range from about 10 ppm to about 50,000 ppm (e.g., in some designs, from about 10 ppm to about 100 ppm; in other designs, from about 100 ppm to about 1000 ppm; in other designs, from about 1000 ppm to about 10,000 ppm; in yet other designs, from about 10,000 ppm to about 50,000 ppm), in some designs. X-ray diffraction may be particularly convenient and easy for identifying the average size of Si nanocrystals. Too small (e.g., smaller than about 1.0 nm in some designs or, e.g., about 2 nm in other designs) Si nanocrystals may exhibit too high reactivity during synthesis and become less active or induce too high first cycle capacity losses, while too large (e.g., larger than about 200 nm in some designs or, e.g., about 100 nm in other designs) Si crystals may reduce cycle stability of such Si-C composites (nanocomposites) or, broadly, nanocomposite silicon. As used here, a “nano”- material (e.g., nanostructure or nanoparticle or nanocomposite, etc.) may refer to any material that exhibits at least one dimension that is less than about 200 nm.

[0057] An aspect is directed to a battery anode and / or a battery anode precursor composition comprising a population of Si-comprising composite particles (e.g., nanocomposite particles, among others), in which each of the Si-comprising composite particles comprises Si and C, and the Si-comprising composite particles have certain characteristics. In some embodiments, a mass fraction of the silicon in the Si-comprising composite particles is in a range of about 3 wt. % to about 80 wt. % (in some designs, from about 3 wt. % to about 20 wt. %; in other designs, from about 20 wt. % to about 35 wt. %; in yet other designs, from about 35 wt. % to about 50 wt. %; in yet other designs, from about 50 wt. % to about 80 wt. %; in yet other designs, from about 50 wt. % to about 60 wt. %; in yet other designs, from about 60 to about 70 wt. %; in yet other designs, from about 70 wt. % to about 80 wt. %; in yet other designs, from about 20 wt. % to about 80 wt. %; in yet other designs, from about 35 wt. % to about 60 wt. %). In some embodiments, a Brunauer-Emmett-Teller (BET) specific surface area (SSA) of the Si- comprising composite particles (e.g., nanocomposite particles, among others) is in a range of about 0.5 m2 / g to about 150 m2 / g (in some designs, from about 0.5 to about 3 m2 / g; in other designs, from about 3 m2 / g to about 12 m2 / g; in yet other designs, from about 12m2 / g to about 18 m2 / g; in yet other designs, from about 18 m2 / g to about 30 m2 / g; in other designs, from about 30 m2 / g to about 50 m2 / g; in yet other designs, from about 50 m2 / g to about 150 m2 / g). In some embodiments, about 90 % or more of the Si-comprising composite particles (e.g., nanocomposite particles, among others) in the population are characterized by aspect ratios of about 2.3 or less, or aspect ratios of about 2.1 or less. In some embodiments, about 50 % or more of the composite particles in the population are characterized by aspect ratios of about 1.25 or more, or aspect ratios of about 1.35 or more.

[0058] An aspect is directed to a battery electrode and / or a battery electrode precursor composition comprising a population of Si-comprising active material particles (e.g., nanocomposite particles, among others), in which the particle population of may be characterized by a particle size distribution (PSD) as determined by laser particle size distribution analysis (LPSA), image analysis of electron microscopy images, or other suitable techniques. The particle size distribution (PSD) that characterizes a particle population may be determined by laser particle size distribution analysis (LPSA) on well- dispersed particle suspensions in one example or by image analysis of electron microscopy images, or by other suitable techniques. While there are diverse processes of measuring PSDs, laser particle size distribution analysis (LPSA) is quite efficient for some applications. Using LPSA, particle size parameters of a population’s PSD can be measured, such as: a tenth-percentile volume-weighted particle size parameter (e.g., abbreviated as Dio), a fiftieth-percentile volume-weighted particle size parameter (e.g., abbreviated as D50), a ninetieth-percentile volume-weighted particle size parameter (e.g., abbreviated as D90), and a ninety-ninth-percentile volume-weighted particle size parameter (e.g., abbreviated as D99). Additionally, parameters relating to characteristic widths of the PSD may be derived from these particle size parameters, such as D50 - Dw (sometimes referred to herein as a left width), D90 - D50 (sometimes referred to herein as a right width), and D90 - Dio (sometimes referred to herein as a full width). A cumulative volume fraction, defined as a cumulative volume of the composite particles with particle sizes of a threshold particle size or less, divided by a total volume of all of the composite particles, may be estimated by LPSA. In some embodiments, a fiftieth-percentile volume- weighted particle size parameter (D50) of the PSD of Si-comprising active material particles may advantageously be in a range of about 0.5 pm to about 25.0 pm, or in a range of about 1.0 or in a range of about 0.5 to about 4.0 pm, or in a range of about 4.0 toabout 6.0 gm, or in a range of about 6.0 to about 8.0 gm or in a range of about 8.0 to about 16.0 gm or in a range of about 16.0 to about 25.0 gm. A cumulative volume fraction, defined as a cumulative volume of the composite particles with particle sizes of a threshold particle size or less, divided by a total volume of all of the composite particles, may be estimated by LPSA. In some embodiments (e.g., when the D50 is in a range from about 0.5 pm to about 4.0 pm), the cumulative volume fraction, with the threshold particle size at about 5 gm, may advantageously be about 99 vol. % or less, or about 95 vol. % or less, or about 90 vol. % or less, or about 85 vol. % or less, or about 80 vol. % or less. In other embodiments (e.g., when the D50 is in a range from about 4.0 gm to about 6.0 gm), the cumulative volume fraction, with the threshold particle size at about 7 gm, may advantageously be about 99 vol. % or less, or about 95 vol. % or less, or about 90 vol. % or less, or about 85 vol. % or less, or about 80 vol. % or less. In other embodiments (e.g., when the D50 is in a range from about 6.0 gm to about 8.0 gm), the cumulative volume fraction, with the threshold particle size at about 10 gm, may advantageously be about 99 vol. % or less, or about 95 vol. % or less, or about 90 vol. % or less, or about 85 vol. % or less, or about 80 vol. % or less. In other embodiments (e.g., when the D50 is in a range from about 8.0 gm to about 16.0 gm), the cumulative volume fraction, with the threshold particle size at about 20 gm, may advantageously be about 99 vol. % or less, or about 95 vol. % or less, or about 90 vol. % or less, or about 85 vol. % or less, or about 80 vol. % or less. In yet other embodiments (e.g., when the D50 is in a range from about 16.0 gm to about 25.0 gm), the cumulative volume fraction, with the threshold particle size at about 30 gm, may advantageously be about 99 vol. % or less, or about 95 vol. % or less, or about 90 vol. % or less, or about 85 vol. % or less, or about 80 vol. % or less. In some embodiments, D50 in a range from about 7.0 gm to about 13.0 gm may be particularly advantageous. In such embodiments, the cumulative volume fraction, with the threshold particle size at about 20 gm, may advantageously be about 99 vol. % or less, or about 95 vol. % or less, or about 90 vol. % or less, or about 85 vol. % or less, or about 80 vol. % or less.

[0059] Note that in some designs the presence of excessively large Si-comprising active material particles (e.g., in the form of nanocomposite particles, among others) may reduce cell performance characteristics (e.g., reduce cell stability, increase its impedance, reduce rate performance, reduce packing density, reduce electrode smoothness or uniformity, reduce electrode mechanical properties, reduce volumetric capacity, increase(e.g., localized) volume expansion, etc.). In some embodiments (e.g., when the D50 is in a range from about 0.5 pm to about 4.0 pm), the cumulative volume fraction, with the threshold particle size at about 10 pm, may advantageously be about 80 vol. % or more, or about 85 vol. % or more, or (in some designs) even about 90 vol. % or more. In some embodiments (e.g., when the D50 is in a range from about 0.5 pm to about 4.0 pm), the cumulative volume fraction, with the threshold particle size at about 12 pm, may advantageously be about 90 vol. % or more, or about 95 vol. % or more, or (in some designs) even about 98 vol. % or more. In other embodiments (e.g., when the D50 is in a range from about 4.0 pm to about 6.0 pm), the cumulative volume fraction, with the threshold particle size at about 15 pm, may advantageously be about 80 vol. % or more, or about 85 vol. % or more, or (in some designs) even about 90 vol. % or more. In other embodiments (e.g., when the D50 is in a range from about 4.0 pm to about 6.0 pm), the cumulative volume fraction, with the threshold particle size at about 25 pm, may advantageously be about 90 vol. % or more, or about 95 vol. % or more, or (in some designs) even about 98 vol. % or more. In other embodiments (e.g., when the D50 is in a range from about 6.0 pm to about 8.0 pm), the cumulative volume fraction, with the threshold particle size at about 18 pm, may advantageously be about 80 vol. % or more, or about 85 vol. % or more, or (in some designs) even about 90 vol. % or more. In other embodiments (e.g., when the D50 is in a range from about 6.0 pm to about 8.0 pm or from about 8.0 pm to about 12.0 pm), the cumulative volume fraction, with the threshold particle size at about 22 pm or about 25 pm, may advantageously be about 80 vol. % or more, or about 85 vol. % or more about 90 vol. % or more, or about 95 vol. % or more, or (in some designs) even about 98 vol. % or more. In other embodiments (e.g., when the D50 is in a range from about 8.0 pm to about 16.0 pm or from about 12.0 pm to about 16.0 pm), the cumulative volume fraction, with the threshold particle size at about 30 pm or about 40 pm, may advantageously be about 80 vol. % or more, or about 85 vol. % or more, or (in some designs) even about 90 vol. % or more. In other embodiments (e.g., when the D50 is in a range from about 8.0 pm to about 16.0 pm), the cumulative volume fraction, with the threshold particle size at about 50 pm, may advantageously be about 90 vol. % or more, or about 95 vol. % or more, or (in some designs) even about 98 vol. % or more. In other embodiments (e.g., when the D50 is in a range from about 7.0 pm to about 13.0 pm), the cumulative volume fraction, with the threshold particle size at about 30 pm, may advantageously be about 90 vol. % or more, or about 95 vol. % or more, or (in somedesigns) even about 98 vol. % or more. In other embodiments (e.g., when the D50 is in a range from about 7.0 gm to about 13.0 gm), the cumulative volume fraction, with the threshold particle size at about 40 gm, may advantageously be about 90 vol. % or more, or about 95 vol. % or more, or (in some designs) even about 98 vol. % or more.

[0060] In one or more embodiments of the present disclosure, Si-comprising active material particles (e.g., Si-comprising active material composite particles) may exhibit true density (e.g., as measured by using nitrogen gas pycnometer, hence in this case sometimes referred to as pycnometer-measured density or pycnometer density or pyc density) in the range from about 1.1 g / cc to about 2.8 g / cc (in some designs, from about 1.1 g / cc to about 1.5 g / cc; in other designs, from about 1.5 g / cc to about 1.8 g / cc; in other designs, from about 1.8 g / cc to about 2.1 g / cc; in other designs, from about 2.1 g / cc to about 2.4 g / cc; in yet other designs, from about 2.4 g / cc to about 2.8 g / cc).

[0061] In one or more embodiments of the present disclosure, Si-comprising active material particles (e.g., Si-comprising active material composite particles) may comprise internal pores. In some designs, the open (e.g., to nitrogen gas at 77K) pore volume (e.g., as measured by nitrogen sorption / desorption isotherm measurement technique and including the pores in the range from about 0.4 nm to about 100 nm) may range from about 0.00 cc / g to about 0.50 cc / g (assuming theoretical density of the individual material components present in Si-comprising active material particles) - in some designs, from about 0.00 cc / g to about 0.10 cc / g; in other designs, from about 0.10 cc / g to about 0.20 cc / g; in other designs, from about 0.20 cc / g to about 0.30 cc / g; in other designs, from about 0.30 cc / g to about 0.40 cc / g; in other designs, from about 0.40 cc / g to about 0.50 cc / g. In some designs, the closed (e.g., to nitrogen gas at 77K) pore volume (e.g., measured by analyzing true density values measured by using an argon gas pycnometer and comparing to the theoretical density of the individual material components present in Si-comprising active material particles) may range from about 0.00 cc / g to about 1.00 cc / g - in some designs, from about 0.00 cc / g to about 0.10 cc / g; in other designs, from about 0.10 cc / g to about 0.20 cc / g; in other designs, from about 0.20 cc / g to about 0.30 cc / g; in other designs, from about 0.30 cc / g to about 0.40 cc / g; in other designs, from about 0.40 cc / g to about 0.50 cc / g; in other designs, from about 0.50 cc / g to about 0.60 cc / g; in other designs, from about 0.60 cc / g to about 0.70 cc / g; in other designs, from about 0.70 cc / g to about 0.80 cc / g; in other designs, from about 0.80 cc / g to about 0.90 cc / g; in other designs, from about 0.90 cc / g to about 1.00 cc / g). In somedesigns, the volume-average size of the open (e.g., to nitrogen gas at 77K) pores may range from about 0.5 nm to about 100 nm - in some designs, from about 0.5 nm to about 5 nm; in other designs, from about 5 nm to about 20 nm; in other designs, from about 20 nm to about 50 nm; in yet other designs, from about 50 nm to about 100 nm. In some designs, the volume-average size of the closed (e.g., to nitrogen gas at 77K) pores (e.g., measured by image analysis of cross-sectional electron microscopy images such as SEM or TEM or measured by the neutron scattering or other suitable technique) may range from about 0.5 nm to about 200 nm - in some designs, from about 0.5 nm to about 5 nm; in other designs, from about 5 nm to about 20 nm; in other designs, from about 20 nm to about 50 nm; in other designs, from about 50 nm to about 100 nm; in yet other designs, from about 100 nm to about 200 nm.

[0062] In one or more embodiments of the present disclosure, Si-comprising active material particles (e.g., Si-comprising active material composite particles) may exhibit moderate (e.g., about 7-120 vol. %) or high (e.g., about 120-250 vol. %) volume changes during initial lithiation (e.g., down to around 0.01 V vs. Li / Li+). In some designs, Si-comprising active material particles may exhibit volume changes in the range from about 8 vol. % to about 180 vol. % during one or more charge-discharge cycles of the battery cell. In one or more embodiments of the present disclosure, Si-comprising active material particles may exhibit moderately small (e.g., about 3-7 vol. %) or moderate (e.g., about 7-120 vol. %) volume changes during electrochemical battery cycling from about 0-5 % state of charge (SOC) to about 90-100 % SOC and back during battery operation.

[0063] In one or more embodiments of the present disclosure, a preferred anode for a battery cell may comprise a mixture of Si-comprising active material particles (e.g., nanocomposite Si-C particles, nanocomposite Si particles, among others, the carbon of which is separate from any carbon that forms part of the Si-comprising active material particles) and graphite active material particles (or, more broadly, carbon active material particles) as the anode active material particles, i.e., a so-called blended anode. In addition to the anode active material particles, an anode may comprise inactive material (separate from any inactive material that is an integral part of the Si-comprising active material composite particles), such as binder(s) (e.g., polymer binder) and / or other functional additives (e.g., surfactants, electrically conductive additives, etc.). In some implementations, the anode active material particles (e.g., Si-comprising active material composite particles, carbon or Gr anode particles in case of a blended anode, etc.) may bein a range of about 85 wt. % to about 98 wt. %of the total weight of the anode (not counting the weight of the current collector) - in some designs, from about 85 wt. % to about 89 wt. %; in other designs, from about 89 wt. % to about 91 wt. %; in other designs, from about 91 wt. % to about 93 wt. %; in other designs, from about 93 wt. % to about 95 wt. %; in yet other designs, from about 95 wt. % to about 98 wt. %.

[0064] In some implementations, blended anodes may comprise Si-comprising active material particles (e.g., Si-C nanocomposite particles, among others) ranging from about 7 wt. % to about 98 wt. % of all the anode active material particles and the graphite (e.g., particles) making up the remainder of the mass (the weight) of the anode active material particles (from about 2 wt. % to about 93 wt. %). In some designs, the Si- comprising active material particles (e.g., Si-C nanocomposite particles, etc.) comprise from about 7 wt. % to about 15 wt. % of the blended anode active material particles; in other designs - from about 15 wt. % to about 25 wt. % of the blended anode active material particles; in other designs - from about 25 wt. % to about 40 wt. % of the blended anode active material particles; in other designs - from about 40 wt. % to about 60 wt. % of the blended anode active material particles; in other designs - from about 60 wt. % to about 80 wt. % of the blended anode active material particles; in yet other designs - from about 80 wt. % to about 98 wt. % of the blended anode active material particles.

[0065] While the descriptions below may also describe certain examples of the blended anode formulations expressed as mass (wt. %) of Si-comprising active material particles (e.g., Si-C nanocomposite particles, among others) among the anode active materials or as mass (wt. %) of Si-comprising active material particles (e.g., Si-C nanocomposite particles, etc.) in the total anode (not counting the weight of the current collector), it will be appreciated that various aspects of this disclosure may be applicable to blended anode formulations expressed as wt. % of Si in the anode (counting the weight of all the active material particles, binder, conductive and / or other additives, but not counting the weight of the current collector). In some implementations, a blended anode composition of about 7 wt. % of Si-comprising active material particles (e.g., Si-C nanocomposite particles, among others) (relative to the total weight of all the active materials in the anode, binder(s), conductive and / or other additive(s), but not counting the weight of the current collector) may correspond, for example, to about 3 wt. % of Si in the blended anode. In some implementations, a blended anode composition of about 19 wt. % of Si-comprising active material particles (e.g., Si-C nanocomposite particles,among others) may correspond, for example, to about 8 wt. % of Si in the blended anode. In some implementations, a blended anode composition of about 35 wt. % of Si- comprising active material particles (e.g., Si-C nanocomposite particles, among others) may correspond, for example, about 15 wt. % of Si in the blended anode. In some implementations, a blended anode composition of about 50 wt. % of Si-comprising active material particles (e.g., Si-C nanocomposite particles, among others) may correspond, for example, to about 21 wt. % of Si in the blended anode. In some implementations, a blended anode composition of about 70 wt. % of Si-comprising active material particles (e.g., Si-C nanocomposite particles, among others) may correspond, for example, to about 30 wt. % of Si in the blended anode. In some implementations, a blended anode composition of about 90 wt. % of Si-comprising active material particles (e.g., Si-C nanocomposite particles, among others) may correspond, for example, to about 38 wt. % of Si in the blended anode. The wt. % of Si in the anode depends on the wt. % of Si in the Si-comprising active material particles, the wt. % of the binder and conductive additives and the wt. % of the graphite in the blended anode. Smaller fractions of inactive materials (e.g., binder and conductive or other additives), higher fraction of Si in the Si-comprising anode material particles (e.g., Si-C composite particles) and smaller fraction of graphite in the blended anode result in higher wt. % Si in the anode. For example, in some implementations, a blended anode composition of about 80 wt. % of Si-comprising active material particles (e.g., Si-C nanocomposite particles, among others) and about 20 wt. % of the total of binder(s), conductive or other additive(s) (if present) and graphite may correspond, for example, to about 30 wt. % of Si in the blended anode. In other implementations, a blended anode composition of about 80 wt. % of Si-comprising active material particles (e.g., Si-C nanocomposite particles, among others) and about 20 wt. % of the total of binder(s), conductive or other additive(s) (if present) and graphite may correspond, for example, to about 40 wt. % of Si in the blended anode. In other implementations, a blended anode composition of about 80 wt. % of Si-comprising active material particles (e.g., Si-C nanocomposite particles, among others) and about 20 wt. % of the total of binder(s), conductive or other additive(s) (if present) and graphite may correspond, for example, to about 50 wt. % of Si in the blended anode. In other implementations, a blended anode composition of about 80 wt. % of Si-comprising active material particles (e.g., Si-C nanocomposite particles, among others) and about 20 wt. % of the total of binder(s), conductive or other additive(s) (if present) and graphite maycorrespond, for example, to about 60 wt. % of Si in the blended anode. In respective implementations, blended anodes may be obtained in which the mass (weight) of the silicon is in a range of about 3 wt. % to about 60 wt. % of a total mass of the anode (not counting the weight of the current collector).

[0066] While the descriptions below may also describe certain examples of the blended anode formulations expressed as mass (wt. %) of Si-comprising active material particles (e.g., Si-C nanocomposite particles, etc.) in the active material blends, it will be appreciated that various aspects of this disclosure may be applicable to blended anode formulations attributing a fraction (e.g., %) of the total capacity of the blended anode to the capacity of the Si-comprising active material particles. In some implementations, for example, about 25 % of the total capacity of the blended anode may be obtained from the Si-comprising active material particles (e.g., Si-C nanocomposite particles, etc.) in a blended anode composition of about 5-8 wt. % of Si-comprising active material particles (e.g., Si-C nanocomposite particles, etc.) relative to the total weight of active material particles (both Si-comprising and graphite active material particles). In some other implementations, as another example, about 50 % of the total capacity of the blended anode may be obtained from the Si-comprising active material particles (e.g., Si-C nanocomposite particles, etc.) in a blended anode composition of about 15-21 wt. % of Si-comprising active material particles (e.g., Si-C nanocomposite particles, etc.). In some other implementations, about 70 % of the total capacity of the blended anode may be obtained from the Si-comprising active material particles (e.g., Si-C nanocomposite particles, etc.) in a blended anode composition of about 30-40 wt. % of Si-comprising active material particles (e.g., Si-C nanocomposite particles, etc.). In some other implementations, about 80 % of the total capacity of the blended anode may be obtained from the Si-comprising active material particles (e.g., Si-C nanocomposite particles, etc.) in a blended anode composition of about 45-55 wt. % of active material Si-comprising active material particles (e.g., Si-C nanocomposite particles, etc.). In some other implementations, about 92 % of the total capacity of the blended anode may be obtained from the Si-comprising active material particles (e.g., Si-C nanocomposite particles, etc.) in a blended anode composition of about 65-75 wt. % of Si-comprising active material particles (e.g., Si-C nanocomposite particles, etc.). In some other implementations, about 95 % of the total capacity of the blended anode may be obtained from the Si-comprising active material particles (e.g., Si-C nanocomposite particles, etc.) in a blended anodecomposition of about 75-85 wt. % of Si-comprising active material particles (e.g., Si-C nanocomposite particles, etc.). In some other implementations, about 98 % of the total capacity of the blended anode may be obtained from the Si-comprising active material particles (e.g., Si-C nanocomposite particles, etc.) in a blended anode composition of about 85-95 wt. % of Si-comprising active material particles (e.g., Si-C nanocomposite particles, etc.). Note that the exact % capacity provided by the Si-comprising active material particles in the blended anode having a specific wt. % of the Si-comprising active material particles depends on the specific capacity of the plurality of the Si-comprising active material particles and the specific capacity of the plurality of graphite (or, broadly, carbon) active material particles.

[0067] In some embodiments, the battery anode composition may advantageously comprise one, two or more carbon-comprising functional additives (e.g., additives that enhance electrical conductivity or rate performance of mechanical properties of the electrode). In some embodiments, the carbon-comprising functional additive(s) is (are) selected from: carbon nanotubes (CNTs) (e.g., single walled carbon nanotubes (SWCNTs), double walled carbon nanotubes (DWCNTs), multi-walled carbon nanotubes (MWCNTs)), carbon nanofibers, carbon black, graphite, graphite ribbons, exfoliated graphite (e.g., exfoliated graphite flakes), graphene oxide (e.g., graphite oxide flakes) and graphene (e.g., flakes) (including, but not limited to, e.g., single-layered and / or multilayered graphene or graphene oxide). In some embodiments, carbon additives may be purified, defective, curved and / or comprise chemical functional groups. In some embodiments, the battery electrode composition may comprise one or more binders (in some designs, two or more binder components).

[0068] An aspect is directed to a battery anode. In some embodiments, the battery anode comprises any of the foregoing battery anode electrode compositions, disposed on and / or in a current collector (e.g., Cu-based or Cu-containing current collector, such as a dense or porous foil or a mesh or a foam or a nanowire-comprising or nanoflakecomprising current collector, etc.). In some embodiments, the battery anode comprises a battery electrode composition and a binder. In some embodiments, a coating density of the battery electrode is in a range of about 0.8 to about 1.7 g / cm3(in some designs, from about 0.8 to about 0.9 g / cm3; in other designs, from about 0.9 to about 1.0 g / cm3; in other designs, from about 1.0 to about 1.2 g / cm3; in other designs, from about 1.2 to about 1.4 g / cm3, in yet other designs, from about 1.4 to about 1.7 g / cm3). Higher fraction of suitablegraphite material in a blended anode may benefit from higher anode density for better performance (e.g., better stability, better rate performance, higher volumetric capacity, lower swell during cycling, etc.), although excessive density may also be detrimental for the same or other characteristics. As such, a detailed optimization may be conducted for a particular battery design, with respect to factors such as electrode thickness, areal capacity loading, battery cycling environment and regime, among other factors.

[0069] An aspect is also directed to a blended battery anode, wherein both the Si- comprising anode active material particles (e.g., nanocomposite Si-C particles, among others) and graphite (or, broadly, carbon-based) active anode material may be present. The anode may preferably comprise a binder amount optimized for the properties of both the Si-comprising active material particles and the graphite particles. For example, the anode may be characterized by an areal binder loading, defined as a mass of the binder in the battery anode (e.g., measured in mg) normalized by the surface area of the active material particles (e.g., Si-comprising (e.g., nanocomposite, etc.) anode active material particles and (if present) graphite active material particles in the same battery anode (e.g., measured in m2and defined by the mass of active material particles (in g) multiplied by the Brunauer-Emmett-Teller (BET) specific surface area (SSA) in m2 / g). Since a BET- SSA of both the Si-comprising active material particle population and the graphite active material particle population may vary from slurry to slurry, the binder loading may preferably be adjusted based on the desired areal binder loading. Higher BET-SSA of the active anode materials (measured in m2 / g) may require a higher mass fraction of the binder in the anode electrode. For example, an anode electrode comprising an active material particle population (e.g., Si-comprising (e.g., nanocomposite, etc.) active anode material particle population or a blend of Si-comprising active material(s) particle(s) and graphite active material(s) particle(s)) with BET-SSA of about 10 m2 / g may require from about 20 mg to about 150 mg of binder per about 1g of active material particles (approximately 2 - 13 wt. % relative to the total weight of the binder and the active material composition, not counting the weight of conductive or other additives or the weight of the current collector), while another anode electrode comprising another active material particle population (e.g., Si-comprising (e.g., nanocomposite, etc.) anode active material particle population or a blend of Si-comprising active material(s) particle(s) and graphite active material(s) particle(s)) with BET-SSA of only about 1 m2 / g may require from about 2 mg to about 40 mg of the binder per about 1g of active material particles(approximately 0.2 - 4 wt. % relative to the total weight of the binder + active material composition, not counting the weight of conductive or other additives or the weight of the current collector). However, in some designs, an areal binder loading of the battery anode in both cases is in a range from about 2.0 mg / m2to about 40.0 mg / m2(e.g. in some designs, from about 2.0 mg / m2to about 5.0 mg / m2; in other designs, from about 5.0 mg / m2to about 9.0 mg / m2; in yet other designs, from about 9.0 mg / m2to about 15.0 mg / m2; in yet other designs, from about 15.0 mg / m2to about 40.0 mg / m2). In some designs, a higher fraction of Si-comprising (e.g., nanocomposite, etc.) anode active material particle population in the anode (relative to the total weight of all active materials) may preferably exhibit a higher areal binder loading. In some designs, a larger average particle size of Si-comprising (e.g., nanocomposite, etc.) anode active material particle population in the anode may preferably require a slightly smaller areal binder loading. In some designs, a larger BET-SSA of Si-comprising (e.g., nanocomposite, etc.) anode active material particle population in the anode may preferably exhibit a slightly higher areal binder loading. In some designs, the areal binder loading may also depend on the binder composition and properties (e.g., adhesion, chemical composition, hardness, elastic modulus when exposed to electrolyte, maximum elongation at break, among others). So, in some designs, the optimal areal binder loading content within a range of about 2.0 mg / m2to about 40.0 mg / m2depends on the anode composition. For example, the optimal areal binder loading content in some designs may range from about 2.0 mg / m2to about 5.0 mg / m2; in other designs, from about 5.0 mg / m2to about 9.0 mg / m2; in yet other designs, from about 9.0 mg / m2to about 15.0 mg / m2; in yet other designs, from about 15.0 mg / m2to about 40.0 mg / m2).

[0070] While the description below may describe certain examples of suitable intercalation-type graphites to be used in combination with Si-comprising (e.g., Si-C nanocomposites, etc.) active material particles in a blend, it will be appreciated that various aspects of this disclosure may be applicable to various soft-type synthetic graphite (or soft carbon, broadly), various hard-type synthetic graphite (or hard carbon, broadly), and various natural graphite (which may, for example, be pitch carbon coated, among others); including but not limited to those which exhibit discharge capacity from about 320 to about 372 mAh / g (e.g., in some designs, from about 320 to about 350 mAh / g; or in other designs, from about 350 to about 362 mAh / g; or in other designs, from about 362 to about 372 mAh / g); including but not limited to those which exhibit low, moderate andhigh swelling; including but not limited to those which exhibit good and poor compression, including but not limited to those which exhibit BET-SSA of about 0.5 to about 40 m2 / g (e.g., in some designs, from about 0.5 to about 2 m2 / g; or in other designs, from about 2 to about 4 m2 / g; or in other designs, from about 4 to about 6 m2 / g; or in other designs, from about 6 to about 8 m2 / g; or in other designs, from about 8 to about 10 m2 / g; or in other designs, from about 10 to about 14 m2 / g; or in other designs, from about 14 to about 20 m2 / g; or in other designs, from about 20 to about 40 m2 / g); including but not limited to those which exhibit lithiation efficiency of about 85-90 % and more; including but not limited to those which exhibit true densities ranging from about 1.5 g / cm3to about 2.3 g / cm3(e.g., in some designs, from about 1.5 to about 1.8 g / cm3, in other designs, from about 1.8 to about 2.3 g / cm3); including but not limited to those which exhibit poor, moderate, or good cycle life when used in Li-ion battery anodes on their own (e.g., without Si-comprising or other active material particles); including but not limited to those which are coated and comprise coatings with coating thickness to appreciably improve compression and springing during cycling.

[0071] An aspect is also directed to a Li-ion battery comprising: (i) a suitable blended battery anode (wherein both the Si-comprising anode active material particles (e.g., nanocomposite Si-C particles, among others) and suitable graphite (or, broadly, carbonbased) active anode material (e.g., graphite active material particles) are present in the anode) and (ii) a suitable battery cathode, wherein the suitable cathode may comprise, in some designs: (iia) intercalation-type cathode or (iib) conversion-type cathode (which may include a displacement-type cathode, a chemical transformation type cathode or a true conversion-type cathode) or (iic) a mixed intercalation / conversion type cathode. Illustrative examples of suitable intercalation-type cathodes to be used in preferable cells may include, but are not limited to, e.g.: lithium nickel cobalt aluminum oxides (NCA), lithium nickel cobalt manganese aluminum oxides (NCMA), lithium nickel oxides (LNO), lithium manganese oxides (LMO) (including, but not limited to high voltage spinels), lithium nickel manganese oxides (LMNO) (including, but not limited to high voltage spinels), lithium nickel manganese cobalt oxides (NCM), lithium cobalt oxide (LCO), lithium cobalt aluminum oxides (LCAO), lithium iron phosphate (LFP), lithium cobalt phosphate (LCP), lithium manganese phosphate (LMP), lithium manganese iron phosphate (LMFP), lithium nickel phosphate (LiNiPCh), lithium vanadium fluoro phosphate (LiVFPCU), lithium iron fluoro sulfate (LiFeSCUF), various Li excess materials(e.g., lithium excess (rocksalt) transition metal oxides and oxy-fluorides such as Li L211Moo.467Cro.3O2, Li1.3Mno.4Nbo.3O2, Li1.2Mno.4Tio.4O2, Lii.2Nio.333 io.333Moo.i3302 and many others), various high capacity Li-ion based materials with partial substitution of oxygen for fluorine or iodine (e.g., rocksalt Li2Mn2 / 3Nbi / 3O2F, Li2Mni / 2Tii / 2O2F, Li1.5Na0.5MnO2.85I0.12, among others) and many other types of Li-comprising disordered, layered, tavorite, olivine, or spinel type active materials or their mixtures comprising at least oxygen or fluorine or sulfur and at least one transition metal and / or other lithium transition metal (TM) oxides or phosphates or sulfates (or mixed) cathode active materials that rely on the intercalation of lithium (Li) and changes in the TM oxidation state (including, but not limited to those that may be doped or heavily doped; including, but not limited to those that have gradient in composition or core-shell morphology; including, but not limited to those that may be partially fluorinated or comprise some meaningful fraction of fluorine (e.g., about 0.001-10 at. %) in their composition, etc.). It will also be appreciated that various aspects may be applicable to high-voltage lithium transition metal oxide (or phosphate or sulfate or mixed or other) cathodes where TMs and oxygen (O) are covalently bonded and both TM and O take part in electrochemical reduction-oxidation (redox) reactions during charge and discharge (including, but not limited to, those oxides or phosphate or sulfate or mixed cathodes that may comprise at least about 0.25 at. % of Mn, Fe, Ni, Co, Nb, Mg, Cr, Mo, Zr, W, Ta, Ti, Hf, Y, La, Sb, V, Sn, Si, or Ge). Illustrative examples of suitable conversion-type cathodes to be used in preferable cells may include, but are not limited to: metal fluorides, metal oxy-fluorides, metal chlorides, metal sulfides, metal selenides, their various mixtures, composites and / or others. Illustrative examples of metal fluorides, in a Li-free state, include, but are not limited to FeFs, FeF2, MnFs, 1F2, NiF2, BiFs, BiFs, SnF2, SnF4, SbFs, SbFs, CdF2, ZnF2, TiFs, TiF4, AgF, AgF2, their various mixtures, alloys and combinations, among others. In some designs, it may be advantageous to produce nanocomposites and / or core-shell structures comprising metal fluorides to enhance their performance and stability. In some designs, it may be advantageous to dope metal fluorides with oxygen or utilize metal oxyfluorides. In a fully lithiated state, pure metal fluorides convert to a composite comprising a mixture of metal and LiF clusters (or nanoparticles). Examples of the overall reversible reactions of the conversion-type metal fluoride cathodes may include 2Li+CuF2^2LiF+Cu for CuF2-based cathodes or 3Li+FeF3^3LiF+Fe for FeFs-based cathodes. It will be appreciated that metal fluoride-based cathodes may be prepared in Li-free or partially lithiated or fully lithiated states. In addition to fluorides, other illustrative examples of conversion-type active electrode materials may include, but are not limited to, various metal oxy-fluorides, sulfo-fluorides, chloro-fluorides, oxy-chloro-fluorides, oxy-sulfo-fluorides, fluoro-phosphates, sulfo-phosphates, sulfo-fluoro-phosphates, mixtures of metals (e.g., Fe, Cu, Ni, Co, Bi, Cr, Zn, Ti, other metals, their various mixtures and alloys, partially oxidized metals and metal alloys, etc.) and salts (metal fluorides (including LiF or NaF), metal chlorides (including LiCl or NaF), metal oxy-fluorides, metal oxides, metal sulfo-fluorides, metal fluoro-phosphates, metal sulfides, metal oxy- sulfo-fluorides, their various combinations, etc.), and / or other salts that comprise halogen or sulfur or oxygen or phosphorous or a combination of these elements, among others. In some designs, F in metal fluorides may be fully or partially replaced with another halogen (e.g., Cl or Br or I, etc.) or their mixtures to form the corresponding metal chlorides or metal fluoride-chlorides and / or other metal halide compositions. Yet another example of a promising and suitable conversion-type cathode active material is sulfur (S) (in a Li- free state) or lithium sulfide (Li2S, in a fully lithiated state). In some designs, selenium (Se) may also be used together with S or on its own for the formation of such cathode active materials. In some designs, it may be advantageous to produce nanocomposites and / or core-shell structures comprising S, Li2S, Se, Li2Se or their various mixtures and combinations to enhance their performance and stability. In some designs, conversiontype active cathode materials may also advantageously comprise metal oxides or mixed metal oxides. In some designs, such (nano)composites may advantageously comprise metal sulfides or mixed metal sulfides. In some examples, mixed metal oxides or mixed metal sulfides may comprise lithium. In some examples, mixed metal oxides may comprise titanium or vanadium or manganese or iron metal. In some examples, lithium- comprising metal oxides or metal sulfides may exhibit a layered structure. In some examples, metal oxides or mixed metal oxides or metal sulfides or mixed metal sulfides may advantageously be both ionically and electrically conductive (e.g., in the range from around 107to around 10+4S / cm). In some examples, various other intercalationtype active materials may be utilized instead of or in addition to metal oxides or metal sulfides. In some designs, such an intercalation-type active material exhibits charge storage (e.g., Li insertion / extraction capacity) in the potential range close to that of S or Li2S (e.g., within around 1.5-3.8 V vs. Li / Li+). In some designs, the use of so-called Li- air cathodes (e.g., cathodes with active material in the form of Li2C>2, Li2O, LiOH in theirlithiation state) or similar metal-air cathodes based on Na, K, Ca, Al, Fe, Mn, Zn and / or other metals (instead of Li) may similarly be beneficial due to their very high capacities. In some designs, such cathode active materials should ideally reversibly react with oxygen or oxygen containing species in the electrochemical cell and may fully disappear upon full de-lithiation (metal removal). Cathode active materials that exhibit such characteristics may also be considered to belong to conversion-type cathodes.

[0072] In some of the preferred examples a surface of cathode active materials (e.g., intercalation-type cathode materials, such as LCO, NCM, NCMA, NCA, LMO, LMNO, LFP, LMP, LMFP, etc. or conversion-type active materials comprising S, Li2S, metal sulfides, metal fluorides, etc.) may be coated with a layer of ceramic material. Illustrative examples of a preferred coating material for such cathodes include, but are not limited to, titanium oxide (e.g., TiCL), tantalum oxide (Ta2Os), aluminum oxide (e.g., AI2O3), tungsten oxide (e.g., WO), chromium oxide (e.g., &2O3), niobium oxide (e.g., NbO or NbO2) and zirconium oxide (e.g., ZrO2), lithium phosphate (e.g., LisPO^, lithium oxy -thiophosphate (e.g., Li3Pi+xO4S4x), and their various mixtures, alloys, and combinations. In some designs, such ceramic materials may additionally comprise lithium (Li) - e.g., as lithium phosphate, lithium oxy -thiophosphate, lithium titanium oxide, lithium tantalum oxide, lithium aluminum oxide, lithium tungsten oxide, lithium chromium oxide, lithium niobium oxide, lithium zirconium oxide and their various alloys, mixtures and combinations. In other preferred examples, LCO, NCM, NCMA, NCA, LFP, LMFP, LMP, LMO or LMNO may be doped with Al, Ti, Mg, Nb, Zr, Cr, Hf, Ta, W, Mo or La. In some designs, a preferred cathode current collector material is aluminum or aluminum alloy. In some designs, a preferred battery cell includes a polymer separator. In some of the preferred examples, a polymer separator is made of or comprises polyethylene, polypropylene or a mixture thereof. In some of the preferred examples, a surface of a polymer separator is coated with a layer of ceramic material. Examples of a preferred coating material for polymer separators may include, but not limited to, titanium oxide (Ti O2), aluminum oxide (AI2O3), aluminum hydroxide or oxyhydroxide, zirconium oxide (ZrCL), magnesium oxide (MgO) or magnesium hydroxide or oxyhydroxide. In some designs, a preferred battery cell includes a ceramic-based or ceramic-comprising (e.g., ceramic / polymer composite) separator. The ceramic or ceramic component of such a ceramic or ceramic-comprising separator may comprise titanium oxide (TiCL), aluminum oxide (AI2O3), aluminum hydroxide or oxyhydroxide, zirconium oxide (ZrCh),magnesium oxide (MgO) or magnesium hydroxide or oxyhydroxide. The ceramic or ceramic component of such a ceramic or ceramic-comprising separator may comprise ceramic particles (e.g., elongated particles, nanofibers, flake-shaped particles, randomly shaped particles including nanoparticles, etc.) in some designs.

[0073] An aspect is directed to a Li-ion battery with a blended anode (e.g., comprising Si-comprising active material and graphite active material, etc.) that exhibits a relatively high areal capacity loading and properly matched (by areal capacity) cathode (e.g., with a slightly smaller areal capacity loading, selected according to the desired negative (N) to positive (P) ratio, N / P in the range of around 1 :01 to around 1 :35 - in some designs, from around 1.01 to around 1.05; in other designs, from around 1.05 to around 1.10; in other designs, from around 1.10 to around 1.15; in other designs from around 1.15 to around 1.20; in other designs from around 1.20 to around 1.25; in yet other designs, from around 1.25 to around 1.35; wherein the N / P ratio corresponds to the ratio of the reversible areal capacities of the anode to cathode). Note that in some designs both the performance characteristics and cycle stability of Li-ion battery cells comprising some of such blended anodes (particularly for blended anodes with high fractions of Si or high fractions of Si-comprising active material particles - e.g., for the blended anodes with about 3-60 wt. % Si; in some designs, with about 3-10 wt. % Si or about 10-20 wt. % Si or about 20-40 wt. % Si or about 40-60 wt. % Si, or for blended anodes with the Si- comprising active material particles (e.g., Si-C nanocomposite particles, among others) contributing to about 20-100% of the total blended anode capacity; in some designs, with about 20-50 % or about 50-70 % or about 70-80 % or about 80-90 % or about 90-95 % or about 95-99 % or about 99-100 % of the total blended anode capacity) may become particularly unsatisfactory for applications requiring long calendar life or long cycle life or low first cycle losses or other properties, if the electrode areal capacity loading exceeds around 1-2 mAh / cm2, even more if the electrode areal capacity exceeds around 4-5 mAh / cm2, and further more if the electrode areal capacity exceeds around 6-8 mAh / cm2. Higher loading, however, is advantageous for reducing cost of energy storage devices and increasing their energy density. One or more embodiments of the present disclosure are directed to synthesis processes, compositions and various physical and chemical properties of graphite(s) and or binder(s) in such blended anodes that provide satisfactory performance for electrode area loadings in the range from around 2 mAh / cm2to around 5 mAh / cm2and more so for loadings in the range from around 5 mAh / cm2to around 8mAh / cm2and even more so for loadings in the range from around 8 mAh / cm2to around 16 mAh / cm2(e.g., in some designs, an areal capacity loading of an electrode composition may range from around 2 mAh / cm2to around 16 mAh / cm2).

[0074] An aspect is directed to a Li-ion battery with a blended anode (e.g., comprising Si-comprising (e.g., composite) active material particles and graphite active material particles, etc.) that exhibits high energy. In some designs, degradation of Li-ion cells with blended anodes not comprising suitable graphite(s) or binder(s) may become particularly undesirably fast for multi-layered (e.g., stacked or rolled) medium sized cells (e.g., cells with cell capacity in the range from 0.2 Ah to around 10 Ah), even more so for large cells (e.g., cells with cell capacity in the range from around 10 Ah to around 40 Ah), even more so for ultra-large cells (e.g., cells with cell capacity in the range from around 40 Ah to around 400 Ah) or gigantic cells (e.g., cells with cell capacity in the range from around 400 Ah to around 4,000 Ah or even more), particularly if the blended anodes comprise moderate-to-relatively high mass fraction of Si (e.g., about 3-60 wt. %; in some designs, about 3-10 wt. % or about 10-20 wt. % or about 20-40 wt. % or about 40-60 wt. %) or if the Si-comprising active material particles (e.g., Si-C nanocomposite particles, among others) contribute to a moderate or a relatively high fraction of the total anode capacity (e.g., about 20-100%; in some designs, about 20-50% or about 50-70% or about 70-80 % or about 80-90% or about 90-95% or about 95-99% or about 99-100%). However, multi-layered medium or large size cells may be attractive for some electronic devices and multi-layered large, ultra-large or gigantic cells may be particularly attractive for use in some electric transportation or grid storage applications. One or more aspects of the present disclosure facilitates the use of proper graphite(s) (or, more broadly carbon(s)) in the blended anodes with suitable microstructural, chemical, physical and / or other properties, and proper binder(s) to mitigate or overcome some or all of such limitations of blended anodes and substantially enhance performance of such Li-ion cells.

[0075] FIG. 1 illustrates an example metal-ion (e.g., Li-ion) battery in which the electrode particles, components, materials, processes, and / or other techniques described herein, or combinations thereof, may be applied according to various embodiments. A cylindrical battery is shown here for illustration purposes, but other types of arrangements, including prismatic or pouch (laminate-type) batteries, may also be used as desired. The example battery 100 includes a negative electrode (anode electrode or anode) 102, a positive electrode (cathode electrode or cathode) 103, a separator 104interposed between the anode 102 and the cathode 103, an electrolyte (shown implicitly) impregnating the separator 104, a battery case 105, and a sealing member 106 sealing the battery case 105. The electrolyte ionically couples the anode (negative electrode) and the cathode (positive electrode). The electrolyte is interposed between the anode electrode and the cathode electrode and ionically couples the anode electrode and the cathode electrode. In some implementations, battery 100 also includes an anode current collector and a cathode current collector. The anode is disposed on and / or in the anode current collector and the cathode is disposed on and / or in the cathode current collector.

[0076] FIG. 2 is a flow diagram of a process 200 of making a Li-ion rechargeable battery cell, such as the example battery 100 of FIG. 1. In the example shown, process 200 includes stages 202, 204, 212, 214, and 220. The flow diagram includes an anode branch (left branch) that includes stages 202 and 204, and a cathode branch (right branch) includes stages 212 and 214. At stage 202, anode particles (e.g., conventional graphite (carbon) anode particles or Si-comprising (e.g., Si-C nanocomposite(s), core-shell, SiOx- based, or SiNx-based, etc.) particles are provided or made, and at stage 204, an anode is formed using the anode particles from stage 202. Similarly, at stage 212, cathode particles (e.g., conventional intercalation-type cathode particles or core-shell cathode particles or composite cathode particles, including conversion-type cathode material - comprising composite particles) are provided or made, and at stage 214, a cathode is formed.

[0077] Electrodes utilized in Li-ion batteries are typically produced by (i) formation of a slurry comprising active materials, conductive additives, binder solutions, and in some cases, surfactant or other functional additives; (ii) casting the slurry onto and / or into a metal foil current collector (e.g., Cu or Cu-alloy foil for most anodes and Al or Al -alloy foil for most cathodes); and (iii) drying the cast electrodes to completely evaporate the solvent. Note that a metal mesh, metal foam or very rough metal foil (e.g., comprising metal nanowires or metal nanosheets on its surface) may be used as current collector(s) in some designs (e.g., for higher areal capacity loadings or for achieving faster charge, etc.). Also note that a metal-coated thin polymer sheet may also be used in some designs as current collector(s) (e.g., to achieve improved safety or lower current collector weight, etc.). Also note that a porous metal foil or composite (e.g., nanocomposite) metal foils may be used in some designs (e.g., for improved properties, lower weight, etc.).

[0078] Stage 204 includes forming an anode electrode, with the anode electrode including the anode particles made or provided at stage 202. For example, stage 204 caninclude (1) making an anode slurry that includes the anode particles (e.g., from stage 202) and other anode slurry components (e.g., binder, additives, etc.) and (2) casting the anode slurry on and / or (in case of a porous current collector) in an anode current collector (e.g., copper foil or copper-alloy foil current collector, porous copper or copper alloy or nickel or nickel alloy foam or foil, or nickel-alloy current collector or polymer-comprising current collector, etc.). For example, other anode slurry components may include: other electrochemically-active anode active materials (e.g., suitable natural or synthetic graphite, soft carbon or hard carbon blended with Si-comprising active material particles, such as Si-C (nano)composite particles), electrically conductive additives (e.g., carbon nanotubes or carbon black or branched carbon or carbon nanofibers or graphite flakes or exfoliated graphite or graphene or graphene oxide or soft graphite or their various combinations), binders (e.g., polymer binders), and solvents (e.g., water or an organic solvent or their mixtures). In some designs, solvent-free (“dry”) electrode fabrication may be utilized.

[0079] Stage 214 includes forming a cathode electrode, with the cathode electrode including the cathode particles made or provided at stage 212. For example, this stage 214 can include (1) making a cathode slurry that includes the cathode particles (e.g., from stage 212) and other cathode slurry components and (2) casting the cathode slurry on and / or (in case of a porous current collector) in a cathode current collector (e.g., aluminum foil or aluminum-alloy foil current collector). For example, other cathode slurry components may include: other electrochemically-active cathode active materials, electrically conductive additives (e.g., carbon nanotubes or carbon black or branched carbon or carbon nanofibers or graphite flakes or graphene or graphene oxide or soft graphite or their various combinations), binders (e.g., polymer binders), and solvents (e.g., water or an organic solvent or their mixtures). In some designs, solvent-free (“dry”) electrode fabrication may be utilized.

[0080] At stage 220, the Li-ion rechargeable battery cell is assembled from at least the anode electrode (e.g., blended anode comprising graphite particles and Si-C (nano)composite particles) and the cathode electrode with an electrolyte interposed between the anode electrode and the cathode electrode. The electrolyte provides ionic conduction between the anode and the cathode. The electrolyte ionically couples the anode and the cathode. The electrolyte may comprise a liquid electrolyte or a solid electrolyte (or a mixture of liquid and solid electrolyte) at battery operating temperatures(e.g., in some designs, the solid electrolyte may be molten or semi-molten during meltinfiltration and may subsequently solidify). In some implementations (e.g., implementations in which a liquid electrolyte is used), a separator may be used to maintain a space between the anode and the cathode electrodes (e.g., to avoid a short- circuit).

[0081] In still further aspects, the step of assembling the battery can comprise positioning a suitable separator that can comprise polymer and / or ceramic components between the cathode and anode electrodes. In other designs, the separator may be omitted (e.g., if a solid electrolyte is used, the solid electrolyte may take the place of the separator). Packaging the battery into a desired configuration (e.g., a cylindrical cell configuration, a prismatic cell configuration, a pouch cell configuration), carrying out electrochemical formation (e.g., formation of a solid-electrolyte interphase (SEI) in the anode and / or a cathode-electrolyte interphase (CEI) in the cathode), degassing, sealing, and aging operations may also be carried out as part of stage 220.

[0082] Battery cell modules or battery cell packs may advantageously comprise cells with electrode and / or electrolyte compositions provided in one or more embodiments of the present disclosure. Such cell modules or packs may offer improved performance characteristics, simplified designs, better safety features or lower cost.

[0083] FIG. 3 is a flow diagram of a process 300 of making anode particles. Process 300 includes stages 302, 304, 306, 308, and 310. At least some of the stages that are optional in some implementations are shown in boxes with dotted lines. Accordingly, stages 304 and 310 are optional in some implementations. In some implementations, the stages may be carried out in the order shown by the arrows. In some designs, process 300 may be particularly useful when implemented as part of stage 202. If suitable modifications are made to process 300 to make cathode particles, process 300 may be implemented as part of stage 212. In some implementations, electrode particles are made using porous carbon particles or porous carbon-containing particles (e.g., using graphitic, sp2-bonded carbon or porous graphitic, sp2-bonded carbon - containing particles), with nanostructured or nano-sized active material particles (e.g., Si -comprising, among others) (e.g., with average diameter or linear dimensions in the range from about 1 nm to about 200 nm (in some designs, from about 1 nm to about 10 nm; in other designs, from about 10 nm to about 30 nm; in yet other designs, from about 30 nm to about 100 nm; in yet other designs, from about 100 nm to about 200 nm), as measured using image analysis ofelectron microscopy (e.g., transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM), scanning electron microscopy (SEM)), X-ray microscopy, X-ray diffraction, neutron scattering and other suitable techniques) being formed in the pores of the porous carbon or porous carbon-containing particles. In the case of anode particles for use in Li-ion batteries, the active material particles may be silicon-comprising particles.

[0084] At stage 302, porous carbon particles are provided. In some designs, carbon (e.g., graphitic, sp2-bonded carbon) particles may be obtained from pyrolysis or carbonization (e.g., by heat treatment or hydrothermal treatment) (in some designs, followed by washing of metal-comprising or impurity compounds; and may be further followed by another heat-treatment or annealing) of a suitable precursor particle, such as a polymer particle or a biomass-derived particle or a metal-organic particle (e.g., with examples of suitable metals or combinations of two, three or more metals include, but are not limited to magnesium (Mg), calcium (Ca), Na, K, among others). In some designs, carbon particles may be obtained from carbon-comprising inorganic precursor particles (e.g., carbides or oxy-carbides, etc.). In some designs, it may be particularly advantageous to utilize Mg-comprising metalorganic compounds (e.g., Mg-comprising organic salts). Herein, processes, materials, and techniques for obtaining carbon-comprising particles by pyrolysis of magnesium (Mg) organic salt compositions are described below in more detail.

[0085] In some designs, inorganic sacrificial templates (including, but not limited to various oxides or hydroxides or oxyhydroxides of various metals and semi-metals - e.g., Zn, Mg, Si, Al, Ti, Ca, Mg, Sc, etc. and their various combinations) or soft (organic) templates may be used for the formation of porous carbon particles. In some designs, the inorganic sacrificial material may be selectively removed (e.g., etched) to form the pores of the porous carbon material. Herein, processes, materials, and techniques for etching metal (e.g., Mg) compounds (e.g., MgO) from precursor particles comprising Mg compounds and carbon, formed by pyrolysis, are described below in more detail.

[0086] In some designs, it may be preferable that the porosity (e.g., specific surface area and specific pore volume) of the porous carbon or carbon-containing particles (e.g., upon completion of stage 302) be quite high (e.g., BET specific surface area of at least about 500 m2 / g) before the formation (e.g., by gaseous deposition) of the nanostructured or nano-sized active material particles therein. In some cases, the precursor particlesthemselves may be highly porous (e.g., BET specific surface area of at least about 500 m2 / g) (e.g., porous carbon particles formed from magnesium organic salt compositions by following the processes as described herein). Nevertheless, in some designs, it may be preferable to produce or enhance porosity in carbon or carbon precursor particles (e.g., by carrying out chemical and / or physical activation on the carbon or carbon-containing particles or by leaching out non-carbon components of carbon-containing particles or by multiple processes) before formation of the active material particles therein to tune the porosity characteristics. Accordingly, stage 304 includes carrying out a porosity enhancing (e.g., an activation) process on the carbon particles (e.g., from stage 302). Stage 304 is optional depending on whether the porous carbon particles from stage 302 meet the porosity requirements for the subsequent formation of active materials, at stage 306.

[0087] For illustration, process 300 is described with respect to the formation of certain electrode (e.g., anode) particles. The concepts of process 300 including porosity enhancing (e.g., an activation) of carbon particles can be applied to other anode particles or with cathode particles that require activation of carbon particles.

[0088] In the example illustrated in FIG. 3, nanostructured or nano-sized silicon (Si) or silicon oxide (SiOx) or silicon nitride (SiNy) or silicon oxy-nitride (SiOxNy) or silicon phosphide (SiPz) particles (0<x<2; 0<y<1.3; 0<z<l) or their various combinations, alloys and mixtures are formed within the pores (and / or on the surface) of porous carbon or porous carbon-containing particles (e.g., mostly graphitic, sp2-bonded porous carbon or mostly graphitic, sp2-bonded carbon-containing particles). For example, stage 306 includes the formation of silicon-based active material particles at least in some of the pores of the porous carbon particles. The formation (e.g., by deposition or infiltration or deposition / infiltration of a Si-comprising precursor with the subsequent conversion to the final Si or Si-based material) of silicon-based active material particles in the porous carbon particles can be accomplished by solution-based or vapor-based deposition processes, in some examples, or by other suitable means. For brevity, the particles upon completion of stage 306 are sometimes referred to as silicon-carbon composite particles (with an understanding that elements other than Si and C may be present within such composite particles in some designs). In some embodiments, such composite particles comprise nano-sized or nanostructured elements (e.g., nano-sized or nanostructured Si, nano-sized or nanostructured C), which may be referred to as nanocomposite particles. In some implementations, the Si or Si-comprising material present in such nanocompositesmay be in the form of nanoparticles. In some implementations, the mass-average size of Si or Si-comprising material nanoparticles may range from about 1 nm to about 200 nm (in some designs, from about 1 nm to about 10 nm; in other designs, from about 10 nm to about 30 nm; in yet other designs, from about 30 nm to about 100 nm; in yet other designs, from about 100 nm to about 200 nm), as measured using image analysis of electron microscopy (e.g., transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM), scanning electron microscopy (SEM)), X-ray microscopy, X-ray diffraction, neutron scattering and other suitable techniques.

[0089] In the example shown, stage 308 is carried out after stage 306. For example, stage 308 includes the formation of a protective coating (e.g., coating of a protective material, comprising carbon and / or an oxide) on and / or in the silicon-carbon (Si-C) composite particles (from stage 306). A protective material comprising carbon may be deposited by a chemical vapor deposition (CVD) process from a hydrocarbon precursor. In some designs, the suitable average thickness of the protective coating may range from about 0.2 nm to about 50 nm (in some designs, from about 0.2 nm to about 2 nm; in other designs, from about 2 nm to about 5 nm; in other designs, from about 5 nm to about 10 nm; in yet other designs, from about 10 nm to about 50 nm). In some designs, the true density of the protective coating may range from about 0.8 g / cc to about 4.8 g / cc or from about 0.8 g / cc to about 5.8 g / cc (in some designs, from about 0.8 g / cc to about 1.6 g / cc; in other designs, from about 1.6 g / cc to about 3 g / cc; in other designs, from about 3 g / cc to about 4.5 g / cc; in yet other designs, from about 4.5 g / cc to about 4.8 g / cc or about 5.8 g / cc).

[0090] In some designs, the protective coating may comprise metal or semimetal oxide or oxy-carbide (including, but not limited to a silicon oxide or silicon oxy-carbide).

[0091] In some designs, the protective coating may comprise or be based on electronically conductive material such as carbon. In some designs, such a carbon coating may be doped (e.g., with B, P, N, O and / or other elements). In some designs, the atomic fraction of individual dopants may range from about 0.01 at. % to about 10.01 at. % (in some designs, from about 0.01 at. % to about 0.1 at. %; in other designs, from about 0.1 at. % to about 1 at. %; in other designs, from about 1 at. % to about 5 at. %; in yet other designs, from about 5 at. % to about 10.01 at. %). In some designs, the protective coating may be largely impermeable to electrolyte solvent.

[0092] During operation of a Li-ion battery cell (e.g., 100 in FIG. 1), the protective coating may reduce or prevent direct contact between the silicon nanoparticles and an electrolyte solvent composition. In some designs, direct contact between the electrolyte solvent composition and the silicon nanoparticles may undesirably accelerate degradation of the Li-ion battery cell.

[0093] In the example shown, stage 310 (other operations) is carried out after stage 308. For example, stage 310 includes making changes to the particle size distribution (PSD). Stage 310 may include carrying out comminution on the protected silicon-carbon composite particles (from stage 308). Comminution may be carried out when the particle sizes are larger (on average) than a final desired (e.g., for a slurry and electrode processing) particle size distribution. Various processes of carrying out comminution are known in the art. For example, the comminution can be carried out by one or more of: ball milling, jet milling, attrition milling, pin milling, and hammer milling. In some implementations, it may be preferable to carry out particle size selection during stage 310. In some cases, stage 310 can include particle size selection (e.g., by sieving or by screening or by centrifugation or by other aerodynamic size classification or by other means) in addition to comminution (e.g., particle size selection after comminution). In some cases, stage 310 can include particle size selection without comminution. For example, it may be preferable to retain some of the larger particle sizes and discard the finer particle sizes. The particle size selection may be carried out by any one of suitable processes known to those skilled in the art, such as screening, sieving, and aerodynamic size classification.

[0094] The foregoing process stage 310 includes examples, such as comminution and particle size selection, of making changes to a particle size distribution (PSD) of a population of particles. In some cases, it may be preferable to employ additional or alternative processes for changing or adjusting a PSD, such as mixing two or more populations of particles wherein each of the populations has a PSD different from others of the populations. For example, particle populations of different PSDs may be obtained (e.g., obtained from a supplier or made to different PSDs including employing the aforementioned processes of comminution and / or particle size selection under different processing conditions).

[0095] The particle size distribution (PSD) that characterizes a particle population may be determined by laser particle size distribution analysis (LPSA), image analysis ofelectron microscopy images, or other suitable techniques. The particle size distribution (PSD) may be determined by laser particle size distribution analysis (LPSA) on well- dispersed particle suspensions in one example. Note that other types of particle size distribution (e.g., by SEM image analysis) could also be utilized (and may even lead to more precise measurements, in some experiments). While there are diverse processes of measuring PSDs, laser particle size distribution analysis (LPSA) is quite efficient for some applications. Using LPSA, particle size parameters of a population’s PSD can be measured, such as: a tenth-percentile volume-weighted particle size parameter (e.g., abbreviated as Dio), a fiftieth-percentile volume-weighted particle size parameter (e.g., abbreviated as D50), a ninetieth-percentile volume-weighted particle size parameter (e.g., abbreviated as D90), and a ninety-ninth-percentile volume-weighted particle size parameter (e.g., abbreviated as D99). Additionally, parameters relating to characteristic widths of the PSD may be derived from these particle size parameters, such as D50 - Dw (sometimes referred to herein as a left width), D90 - D50 (sometimes referred to herein as a right width), D90 - Dw (sometimes referred to herein as a full width), and (D90 - D ) / Dso (sometimes referred to herein as a span). A cumulative volume fraction, defined as a cumulative volume of the composite particles with particle sizes of a threshold particle size or less, divided by a total volume of all of the composite particles, may be estimated by LPSA. In some embodiments, a fiftieth-percentile volume-weighted particle size parameter (D50) of the PSD is in a range of about 1.0 pm to about 20.0 pm, or in a range of about 2.0 pm to about 16.0 pm, or in a range of about 2.0 to about 4.0 pm, or in a range of about 4.0 to about 6.0 pm, or in a range of about 6.0 to about 8.0 pm or in a range of about 8.0 to about 16.0 pm, or in a range of about 16.0 pm to about 20.0 pm. In some embodiments, (D90 - D ) / Dso may preferably be in the range from about 0.5 to about 6, or in a range of about 0.5 to about 1 or in a range of about 1 to about 2 or in a range from about 2 to about 4 or in a range from about 4 to about 6. Smaller value of a span (more narrow particle size distribution) may be advantageous in some designs.

[0096] Upon completion of the operations in process 300 (e.g., stages 302, 304, 306, 308, 310), the composite particles may be characterized by a Brunauer-Emmett-Teller (BET) specific surface area (SSA) (e.g., obtained from the data of nitrogen sorptiondesorption at cryogenic temperatures, such as about 77K). In some embodiments, the BET-SSA of the composite particles is in a range of about 1 m2 / g to about 50 m2 / g (in some designs, from about 1 to about 3 m2 / g; in other designs, from about 3 m2 / g to about12 m2 / g; in yet other designs, from about 12 m2 / g to about 18 m2 / g; in yet other designs, from about 18 m2 / g to about 30 m2 / g; in yet other designs, from about 30 m2 / g to about 50 m2 / g).

[0097] FIG. 4 is a schematic illustration of an example process of making porous carbon particles. This example process exemplifies a new technology that is based on a transformational use of carbon as a sustainable building block for batteries in the form of high-throughput Si-C composites generated from environmentally friendly carbon feedstock (e.g., the carbon feedstock may be biogenic in some implementations) and recyclable porogen (pore-forming material). In some implementations, the porogen may generate the necessary pore volumes for high-energy Si-C anode cells without any activation. In some other implementations, processes may combine the use of the porogen with subsequent activation; in some cases, the duration of the activation may be reduced compared to other processes in which no porogen is employed. The new technologies demonstrated here may be employed to manufacture porous carbon particles (and subsequently, Si-C (nano)composite particles, for example) at significantly lower cost, lower energy consumption, and / or greater use of recycled materials (e.g., recycled porogen material). In some example processes, a greater tunability of certain porosity characteristics (e.g., total pore volume, volume of micropores, volume of mesopores, volume of macropores, volume of pores in a range of about 2 to about 5 nm, volume of pores in a range of about 2 to about 7 nm, volume of pores in a range of about 2 to about 10 nm, etc.) may be attained using the processes outlined in FIG. 4 and as described herein. In some implementations, porous carbon particles are generated from environmentally friendly, broadly available (at quantities of greater than millions of tons per year), low-cost biogenic carbon feedstock and a recyclable commodity chemical. Accordingly, it will become possible to reimagine raw material sourcing, reduce the GHG emissions during LIB manufacturing, and achieve outstanding service life. Most importantly, by significantly improving LIB performance and reducing LIB costs, these technologies will meaningfully accelerate EV adoption and thus make a major impact on the global reduction of CO2 emissions (up to 1 Gigaton CO2 eq.).

[0098] The inventors discovered a novel synthetic pathway for synthesizing highly porous C scaffold particles. In some implementations, the particle size distribution, the particle shape, pore shape, and / or the pore size distribution of the porous carbon particles may be tuned. A porogen may be used to afford better control of the porosity. The porogenmay be a commodity chemical and may be of relatively low cost and / or be recyclable. In some processes that employ the porogens, carbonization and activation processes that generate a high fraction of CO and CO2 byproducts may be unnecessary.

[0099] FIG. 4 shows a schematic illustration of process 400 of making porous carbon particles. Initially, a carbon precursor 402 and a porogen 404 are provided. In some implementations, each of the carbon precursor and the porogen may be a commodity chemical and may also be of low cost and / or be biogenic. The carbon precursor 402 and the porogen 404 undergo mixing and / or other processing (406) until a carbon precursor- porogen mixture, in suitable form, is obtained (408). The carbon precursor-porogen mixture is pyrolyzed (410) to obtain a carbon-porogen composite (412). The carbon- porogen composite (412) undergoes a washing process (414) that includes etching of the composite with an etchant. The etchant may be a liquid etchant such as an acid. A variety of acids may be employed, including stronger acids (e.g., sulfuric acid, hydrochloric acid) and weaker acids (e.g., citric acid, acetic acid, carbonic acid). The etching process may remove most of or substantially all of the porogen from the composite and the resulting product is a porous carbon scaffold (porous carbon particles) 416. During the washing process, impurities may also be removed. In some implementations, a recovery process 418 may be carried out to recover some or all of the porogen 404 which may be reused in a subsequent synthesis process. One finding of interest is that the pore volume (e.g., total pore volume) may be tuned over a wide range by variation of the porogen content.

[0100] In some implementations, a magnesium compound (e.g., MgO) may be employed as the porogen. For example, when MgO is mixed with citric acid, magnesium citrate is formed. In some implementations, certain magnesium organic salts may be employed in the synthesis of porous carbon particles. FIGS. 5A and 5B illustrate example magnesium organic salts. Possible variations of magnesium citrate include the dibasic form (shown as structure 502) and the tribasic form (shown as structure 504). The dibasic form has the Mg atom and the citrate ligand in a 1 : 1 ratio of Mg to citrate. The tribasic form has the Mg atom and the citrate ligand in a 3 :2 ratio of Mg to citrate and is sometimes referred to as trimagnesium dicitrate or trimagnesium citrate. The tribasic form may be present as a nonahydrate compound. Herein, experimental results referring to magnesium citrate are to the tribasic form unless otherwise specified. Magnesium acetate (as a tetrahydrate compound) is shown as structure 506. Other magnesium organic salts include: magnesium stearate (508), magnesium lactate (magnesium L-lactate hydrate isshown as structure 510), magnesium ascorbate (magnesium L-ascorbate is shown as structure 512), and magnesium gluconate (magnesium D-gluconate hydrate is shown as structure 514).

[0101] The inventors have carried out pyrolysis studies of solid samples of magnesium citrate (tribasic 504, dibasic 502), magnesium acetate 506, and other magnesium organic salts (508, 510, 512, 514). A solid product of the pyrolysis of magnesium acetate has been found to contain no carbon; only MgO was present in the solid product. Similarly, a solid product of the pyrolysis of magnesium stearate has been found to contain no carbon; only MgO was present in the solid product. The MgO may be etched in the subsequent washing process 414 and pores are formed in the space left vacant by the etched MgO. Accordingly, in some implementations, magnesium acetate and magnesium stearate may be employed as a material that contributes MgO but little or no carbon to the carbon-porogen composite (e.g., 412 in FIG. 4). On the other hand, solid products of the pyrolysis of tribasic magnesium citrate 504, dibasic magnesium citrate 502, and certain other magnesium organic salts (e.g., magnesium lactate, magnesium ascorbate, magnesium gluconate) were found to contain carbon and MgO. Herein, such magnesium organic salts may be referred to as carbon-yielding magnesium organic salts.

[0102] FIG. 6A is a flow diagram of an example process 600 of making porous carbon particles. In the example shown, process 600 includes stages 602, 604, 606, 608, and 610. Stage 602 includes preparing a solution (e.g., aqueous solution) of a magnesium organic salt composition. The magnesium organic salt composition includes a carbon-yielding magnesium organic salt. In some implementations, the magnesium organic salt composition includes a higher-C yielding magnesium organic salt and a lower-C yielding magnesium organic salt. At stage 604, particles of the magnesium organic salt composition are precipitated from the solution. For example, this may be accomplished by vaporizing the solvent. Accordingly, in some implementations, the concentration of the magnesium organic salt composition in the solvent is sufficiently low to allow full dissolution of the magnesium organic salt composition in the solvent. However, if the concentration is too low, too much energy may be expended in vaporizing the solvent at stage 604. Stage 604 may additionally include drying the particles of the magnesium organic salt composition. Stage 606 includes carrying out pyrolysis on the particles from stage 604 to obtain precursor composite particles comprising carbon and at least one magnesium compound. The precursor composite particles may be characterized by anaverage particle size (e.g., D50) of at least about 0.1 mm (e.g., at least about 0.3 mm, 1.0 mm). In some implementations, at least one magnesium compound comprises MgO. In some implementations, the pyrolysis operation includes heating the sample (e.g., particles of the magnesium organic salt composition) to a steady-state temperature in a range of about 750 to about 1200 °C (e.g., in a range of about 750 to about 850 °C, or in a range of about 850 to about 950 °C, or in a range of about 950 to about 1050 °C, or in a range of about 1050 to about 1200 °C, or in a range of about 750 to about 1050 °C) and maintaining the steady-state temperature for a predetermined time period (e.g., in a range of about 0.1 hr to about 0.2 hr, or in a range of about 0.2 hr to about 0.4 hr, or in a range of about 0.4 hr to about 0.6 hr, or in a range of about 0.6 hr to about 0.8 hr, or in a range of about 0.8 hr to about 1.0 hr). In some implementations, it may be preferable to set the steady-state temperature below about 1200 °C, to minimize or reduce the occurrence of carbothermal reduction of MgO. In some implementations, it may be preferable to carry out the pyrolysis in an inert atmosphere, such as N2, Ar, or He. Stage 608 includes selectively removing the magnesium compound(s) from the precursor composite particles by etching, to form porous carbon particles. The etching may be carried out by exposing the precursor composite particles to an etchant. The etchant may be a liquid etchant such as an acid. A variety of acids may be employed, including stronger acids (e.g., sulfuric acid, hydrochloric acid) and weaker acids (e.g., citric acid, acetic acid, carbonic acid). Stage 608 may also include, after the etching, separation of the solids (e.g., the porous carbon particles) from the liquid. The porous carbon particles may be characterized by an average particle size (e.g., D50) of at least about 0.1 mm (e.g., at least about 0.3 mm, 1.0 mm). Stage 608 may also include additional washing and / or drying of the porous carbon particles. Stage 610 is optional and may be carried out after stage 608. Other suitable operations may be carried out at stage 610. Stage 610 may include recovery of the etchant acid in magnesium salt form. For example, if acetic acid is employed as an etchant stage 608, then the acetic acid may be recovered in magnesium salt form (i.e., a magnesium acetate) at stage 610. The recovered magnesium acetate may be reused in a synthetic process that uses magnesium acetate. Stage 610 may also include an activation process (e.g., physical activation, chemical activation) to increase the porosity of the porous carbon particles. However, as discussed below, suitable porosities may be attained without relying on such activation processes.

[0103] FIG. 6B is a flow diagram of an example process 620 of making porous carbon particles. Process 620 is simplified compared to process 600 (FIG. 6A). The operations of preparing a solution of the Mg organic salt composition in a solvent (602) and then precipitating particles of the Mg organic salt composition from the solution (604) are avoided. In the example shown, process 620 includes stages 622, 606, 608, and 610. Stage 622 includes providing a magnesium organic salt composition. Stage 602 is followed by stages 606, 608, and 610, which are as described with reference to FIG. 6A. This synthetic pathway of process 620 of FIG. 6B may be used when (1) the Mg organic salt composition does not require mixing in solution (e.g., the Mg organic salt composition comprises a sole Mg salt), and / or (2) the Mg organic salt composition is readily available in solid form.

[0104] FIGS. 7A, 7B, 7C, and 7D are flow diagrams of example processes (700, 710, 720, 730) of preparing a solution of a magnesium organic salt composition. Each of the processes 700, 710, 720, and 730 may correspond to an example implementation of stage 602 (FIG. 6A). Process 700 (FIG. 7A) includes stages 702, 704, and 706. Stage 704 is optional. Stages 702 and 704 may be carried out concurrently and include providing a higher-carbon yielding Mg salt and a lower-carbon yielding Mg salt, respectively. In some implementations, the lower-C yielding Mg salt may be a Mg salt that yields MgO but yields no carbon (e.g., magnesium acetate, magnesium stearate) and the higher-C yielding Mg salt may be a salt that yields MgO and carbon (e.g., tribasic magnesium citrate, dibasic magnesium citrate, magnesium lactate, magnesium ascorbate, magnesium gluconate). Other combinations of Mg salts are also possible. The lower-C yielding Mg salt may also be a salt that yields MgO and carbon. Under some experimental conditions, the carbon yield of magnesium lactate has been found to be lower than that of magnesium citrate (tribasic and dibasic). Under some experimental conditions, the carbon yield of magnesium ascorbate has been found to be higher than that of magnesium citrate (tribasic and dibasic). Furthermore, under some experimental conditions, the carbon yield of magnesium gluconate has been found to be higher than those of magnesium ascorbate and magnesium citrate (tribasic and dibasic). The carbon yield of a Mg salt may be determined by carrying out pyrolysis on the Mg salt and determining the mass fraction of carbon in the pyrolysis product (e.g., by thermogravimetric analysis (TGA)). The carbon yield of an Mg salt may be calculated as the moles of carbon (per mole of Mg) found in the pyrolysis product, divided by moles of carbon (per mole of Mg) in the Mg salt. Otherexample Mg salt combinations are possible, such as: magnesium citrate (tribasic or dibasic) as a higher-C yielding Mg salt and magnesium lactate as a lower-C yielding Mg salt; and magnesium ascorbate as a higher-C yielding Mg salt and magnesium lactate as a lower-C yielding Mg salt.

[0105] Stage 706 (FIG. 7A) includes preparing a solution (e.g., an aqueous solution) of the higher-C yielding Mg salt (from stage 702) (e.g., magnesium citrate) and the lower- C yielding Mg salt (from stage 704) (e.g., magnesium acetate). In some implementations, the lower-C yielding Mg salt may be omitted from the Mg salt solution. Since the higher- C yielding Mg salt yields MgO, porous carbon particles may be obtained upon etching in an etchant even if only the higher-C yielding Mg salt is used.

[0106] Process 710 (FIG. 7B) includes stages 712, 714, and 716. Stages 712 and 714 may be carried out concurrently and include preparing a solution (e.g., aqueous solution) of a higher-carbon yielding Mg salt (e.g., magnesium citrate, tribasic or dibasic) and a solution (e.g., aqueous solution) of a lower-carbon yielding Mg salt (e.g., magnesium acetate), respectively. Stage 716 includes mixing the two solutions from stages 712 and 714.

[0107] Process 720 (FIG. 7C) includes stages 722, 724, and 726. Stages 722 and 724 may be carried out concurrently. Stage 722 includes preparing a solution (e.g., aqueous solution) of a first magnesium organic salt. Stage 724 includes preparing an acid solution. Stage 726 includes mixing the two solutions from stages 722 and 724. Upon mixing, the anions of the acid at least partially displace the ligand of the magnesium organic salt in the mixed solution. Accordingly, when solids are precipitated from the mixed solution (e.g., stage 604), the solids contain a hybrid magnesium salt comprising two ligands: (1) the first ligand is from the first magnesium organic salt, and (2) the second ligand is the anion of the acid. In one example, the first magnesium organic salt may be magnesium acetate (MgAc?) and the acid may be citric acid. In this example, mixing and precipitation results in the formation of a hybrid Mg salt that can be written as Mg3Cit2-xAc3x, with x varying between 0 and 2 depending upon preparation conditions, such as the relative amounts (relative number of moles) of the MgAc? and citric acid. Experimental results obtained from porous carbon particles synthesized by this pathway are reported in FIGS. lOA and 10B.

[0108] Process 730 (FIG. 7D) includes stages 732, 734, and 736. Stages 732 and 734 may be carried out concurrently. Stage 732 includes providing a magnesium compound(e.g., MgO). In some implementations, stage 732 includes dispersing the magnesium compound in a solvent. Stage 734 includes preparing an acid solution. Stage 736 includes mixing the magnesium compound (or the solution comprising the magnesium compound) (from 732) and the acid solution (from 724). Upon mixing, the magnesium compound and the acid react to form a magnesium organic salt in which its ligands are the anions of the acid. In one example, the magnesium compound may be MgO and the acid may be citric acid. In this example, mixing and precipitation results in the formation of magnesium citrate.

[0109] FIGS. 8 A and 8B show scanning electron microscope (SEM) images of example porous carbon particles. The SEM images were taken in cross section after ion beam polishing. FIG. 8A shows an SEM image of porous carbon particles that were formed by pyrolysis (900 °C, N2) of commercially available tribasic magnesium citrate nonahydrate and etching in sulfuric acid (H2SO4) (the synthesis procedure follows process 620 of FIG. 6B). FIG. 8B shows an SEM image of porous carbon particles that were formed by pyrolysis (900 °C, N2) of magnesium citrate formed by process 730 and etching in acetic acid (the subsequent synthesis procedure to make the porous carbon particles follows process 600 of FIG. 6A). Details of the synthesis of the porous carbon particles of FIGS. 8A and 8B are reported as Examples 1 and 2 herein. Synthetic conditions appear to have a significant effect on the pore structure of the porous carbon particles. For example, elongate macropores (dimensions of at least 50 nm) are visible in the FIG. 8A porous carbon particle whereas the FIG. 8B porous carbon particle exhibits a more uniform interior without visible macropores.

[0110] FIG. 9 shows a graphical plot of the dependence of a total pore volume (TPV) of porous carbon particles (i.e., after selective removal of MgO) on the mass fraction of MgO in the precursor composite particles. The porous carbon particles studied in FIG. 9 were formed by pyrolysis (900 °C, N2) of commercially available tribasic magnesium citrate nonahydrate and etching in sulfuric acid (H2SO4) (the synthesis procedure follows process 620 of FIG. 6B). Each of the samples reported in FIG. 9 was maintained at the steady-state temperature of 900 °C for 0.5 hr. Details of the synthesis of the porous carbon particles of FIG. 9 are reported as Example 3 herein. Unexpectedly, the inventors found that the mass fraction of MgO in the precursor composite particles depends on (1) the temperature ramp rate (from room temperature to the steady-state pyrolysis temperature of 900 °C), and (2) the mass of the sample of magnesium citrate placed in a quartz cruciblefor pyrolysis. The leftmost data point 902 (MgO mass fraction of about 73 wt. %, total pore volume of about 1.25 cm3 / g) corresponds to a temperature ramp rate of about 5 °C / min and magnesium citrate sample of about 20 g. The rightmost data point 904 (MgO mass fraction of about 87 wt. %, total pore volume of about 2.00 cm3 / g) corresponds to a temperature ramp rate of about 15 °C / min and magnesium citrate sample of about 60 g. In between these extrema, the MgO mass fraction increased with increasing temperature ramp rate and increasing magnesium citrate sample mass. In the pyrolysis of biomass to obtain biochar, the biochar yield is known to decrease with increasing temperature ramp rate, under certain conditions. This known trend is consistent with the finding of increasing MgO mass fraction, which corresponds to decreasing carbon mass fraction, with increasing temperature ramp rate. Notably, the results of FIG. 9 demonstrate that porous carbon particles with high porosities (e.g., a total pore volume (TPV) of up to about 2.0 cm3 / g, in this example) may be obtained by the pyrolysis and subsequent processing of magnesium organic salt compositions, without any activation (e.g., any additional activation being performed after completion of the MgO selective removal (etching)). Furthermore, the results of FIG. 9 demonstrate that the porosity can be tuned over a wide range (e.g., TPV in a range of about 1.25 to about 2.0 cm3 / g, in this example) for a composition comprising a sole C-yielding magnesium organic salt (e.g., magnesium citrate) without the addition of a magnesium organic salt that does not yield carbon (e.g., magnesium acetate).

[0111] FIG. 10A shows a graphical plot of the dependence of a total pore volume (TPV) of porous carbon particles (i.e., after selective removal of MgO) on the value of acetate content parameter x characterizing the fraction of the acetate ligand in hybrid magnesium salts comprising citrate and acetate ligands of the form Mg3Cit2-xAc3x. For the porous carbon particles studied in FIG. 10 A, solutions of magnesium organic salt compositions were formed according to process 720 of FIG. 7C (the first magnesium organic salt was magnesium acetate (MgAc?), and the acid was citric acid). For each sample, porous carbon particles were formed by pyrolysis (900 °C, N2) of particles of magnesium organic salt compositions and etching in sulfuric acid (H2SO4) (the synthesis procedure follows process 600 of FIG. 6A), with the acetate content parameter being varied between 0 (no acetate added) and 1.0. Details of the synthesis of the porous carbon particles of FIG. 10A are reported as Example 4 herein. Notably, the results of FIG. 10A demonstrate that porous carbon particles with high porosities (e.g., a total pore volume(TPV) of up to about 2.1 cm3 / g, in this example) may be obtained by the pyrolysis and subsequent processing of hybrid magnesium salts comprising citrate and acetate ligands. Herein, the term “subsequent processing” may refer to the selective removal of the magnesium compounds (e.g., MgO) from the precursor composite particles (608). Furthermore, the results of FIG. 10A demonstrate that the porosity can be tuned over a wide range (e.g., TPV in a range of about 1.25 to about 2.1 cm3 / g, in this example) by tuning the acetate content in the hybrid magnesium salts comprising citrate and acetate ligands.

[0112] FIG. 10A reports the acetate content of the hybrid magnesium salts in terms of the acetate content parameter x. FIG. 10B (Table 1) shows, for each listed value of the acetate content parameter x (ranging between 0.0 and 1.0): (1) the molecular mass of the citrate ligand Cit2-X, (2) the molecular mass of the acetate ligand Ac3x, (3) the total mass of one mole of the hybrid magnesium salt of the form Mg3Cit2-xAc3x, and (4) the mass fraction of acetate ligands in a total mass of the ligands (sum of the masses of the acetate ligand Ac3x and the citrate ligand Cit2-X). Accordingly, Table 1 (FIG. 10B) provides conversion between the acetate content parameter x and the acetate mass fraction in the total mass of the ligands.

[0113] According to FIG. 10A, there may be a trend of increasing pore volumes (e.g., TPV) with increasing acetate content parameter x for relatively low values of x (e.g., x in a range of about 0 to about 0.9, or in a range of about 0 to about 0.8, or in a range of about 0 to about 0.7, or in a range of about 0 to about 0.6, or in a range of about 0 to about 0.5). For larger values of x (e.g., x greater than about 0.9, or greater than about 0.8, or greater than about 0.7, or greater than about 0.6, or greater than about 0.5), there may be a trend of decreasing pore volumes (e.g., TPV) with increasing acetate content parameter x. Accordingly, for obtaining porous carbon particles of relatively high porosities, the acetate content parameter x may be in a range of about 0.25 to about 1.0, or in a range of about 0.3 to about 0.9, or in a range of about 0.5 to about 0.7, in some implementations. For obtaining porous carbon particles of relatively high porosities, the mass fraction of acetate ligand in a total mass of the ligands may be in a range of about 22 to about 66 wt. %, or in a range of about 25 to about 61 wt. %, or in a range of about 39 to about 51 wt. %, in some implementations.

[0114] In some designs, it may be preferable that the porosity of the porous carbon particles (e.g., specific surface area and specific pore volume) be quite high before theformation of the nanostructured or nano-sized active material particles therein. In some implementations, it is preferable that the porous carbon particles exhibit a Brunauer- Emmett-Teller (BET) specific surface area (SSA) (e.g., obtained from the data of nitrogen sorption-desorption at cryogenic temperatures, such as about 77K) of about 500 m2 / g or more, before formation of the active material (e.g., Si-comprising active material) particles therein. In some implementations, it is preferable that the porous carbon particles exhibit a BET specific surface area in a range of about 500 m2 / g or about 1000 m2 / g to about 3500 m2 / g or about 4500 m2 / g or about 4800 m2 / g (e.g., in some designs, from about 500 to about 1000 m2 / g; in other designs, from about 1000 to about 3500 m2 / g, in other designs, from about 1800 to about 3500 m2 / g, in other designs, from about 1000 to about 2000 m2 / g; in other designs, from about 2000 to about 3000 m2 / g; in other designs, from about 3000 to about 3800 m2 / g; in other designs, from about 3000 to about 4500 m2 / g; in yet other designs, from around 3800 to about 4800 m2 / g), before formation of the active material particles therein.

[0115] In some implementations, it is preferable that the porous carbon particles exhibit a total pore volume (TPV) in a range of about 0.5 to about 5.0 cm3 / g (e.g., in some designs, in a range from about 0. 5 to about 1.2 cm3 / g; in other designs, from about 1.2 to about 2.5 cm3 / g, in other designs, from about 1.8 to about 2.2 cm3 / g; in other designs from about 0.5 to about 1.0 cm3 / g; in other designs, from about 1.0 to about 1.5 cm3 / g; in other designs, from about 1.5 to about 2.0 cm3 / g; in other designs, from about 2.0 to about 2.5 cm3 / g; in other designs, from about 2.5 to about 3.0 cm3 / g; in other designs, from about 3.0 to about 4.0 cm3 / g; in yet other designs, from about 4.0 cm3 / g to about 5.0 cm3 / g). In some implementations, it is preferable that the porous carbon particles exhibit a cumulative pore volume for pores in the micropore (< 2 nm) and mesopore (2 to 50 nm) size ranges (but not counting macropores, > 50 nm) in a range of about 0.5 cm3 / g to about 5 cm3 / g (e.g., in some designs, from about 0.5 to about 1.0 cm3 / g; in other designs, from about 1.0 to about 2.0 cm3 / g; in other designs, from about 2.0 to about 3.5 cm3 / g; in yet other designs, from about 3.5 to about 5 cm3 / g), before formation of the active material particles therein.

[0116] FIG. 11 shows a graphical plot of the dependence of the gravimetric charge capacity (expressed as a fraction of the cycling-start charge capacity) on cycle number, of lithium-ion battery test cells in which the anodes comprise silicon-carbon composite particles made from porous carbon particles as described herein. For the porous carbonparticles used in FIG. 11, a solution of magnesium citrate was prepared, and magnesium salt particles were obtained by precipitation. Porous carbon particles were formed by pyrolysis (900 °C, N2) of the magnesium salt particles and etching in sulfuric acid (H2SO4) (the synthesis procedure follows process 600). Details of the synthesis of the porous carbon particles of FIG. 11 are reported as Example 5 herein. Silicon-carbon composite particles were formed from the porous carbon particles in accordance with process 300. Lithium-ion battery test cells with a blend of graphite and the silicon-carbon composite particles in the anode and a lithium nickel cobalt manganese oxide active material of approximate composition LiNio.8Coo.1Mno.1O2 (NCM811) in the cathode were fabricated and tested as described in Example 6 herein. FIG. 11 shows the capacity retention performance of six test cells, and the actual N80 is about 640-780 cycles (during cycling at 25 °C). The number of cycles to reach 80 % of cycling start capacity is also referred to as N80. N80 is a convenient metric of the cycle life of a battery cell. The cycling start capacity is defined as the capacity at cycling start (e.g., at cycle 3, after formation cycles up to cycles 2).

[0117] FIG. 12A is a schematic illustration of a chemical reaction (Formula Al, 1202) in the etching of MgO by citric acid (HOC(CO2H)(CH2CO2H)2). Formula Al (1202) shows that the etching of MgO (e.g., in an MgO-C composite) by citric acid results in the direct formation of tribasic magnesium citrate (MgsCit2). The reaction regenerates magnesium citrate for use in subsequent pyrolysis.

[0118] FIG. 12B is a schematic illustration of chemical reactions (Formula Bl, 1204) in the etching of MgO by sulfuric acid (H2SO4). In the example shown, precursor composite particles (MgO-C composite), immersed in water, are etched by sulfuric acid, resulting in the formation of soluble Mg2+ions in dilute H2SO4. This etching reaction does not directly yield any C-yielding magnesium organic salts. A second reaction may be carried out to neutralize the acid and basify the Mg2+ions, by addition of sodium bicarbonate (NaHCOs). This second reaction results in the formation of water-soluble Mg species (Mg(HCO3)2) and a water-soluble waste salt ([2Na+] [SO42']). A third reaction may be carried out to degas (i.e., extract CO2 from) the water-soluble Mg species (Mg(HCO3)2) by boiling to form water-insoluble Mg(COs) in solid form. The Mg(COs) decarboxylates upon heating to about 350 °C (or higher), forming MgO. As shown in Formula Al, MgO can be converted to magnesium citrate for use in subsequent pyrolysis.

[0119] FIG. 12C is a schematic illustration of chemical reactions in the etching of MgO by carbonic acid (H2CO3). FIG. 12C shows Formula Cl (1206), Formula C2 (1208), Formula C3 (1210), Formula C4 (1212), Formula C5 (1214), Formula C6 (1216), and Formula C7 (1218). Formula Cl shows that MgO, when immersed in water, undergoes a conversion to Mg(OH)2 in an exothermic reaction. Formula C3 shows a general reaction in which an acid of a form HA reacts with Mg(OH)2 to form water-soluble Mg2+cations, water-soluble A anions, and water. This general reaction pathway may be applicable to etching by any of the suitable acids, such as sulfuric acid, hydrochloric acid, citric acid, acetic acid, and carbonic acid. Carbon dioxide gas may be dissolved in water (Formula C4), and the dissolved carbon dioxide reacts with water to form carbonic acid (H2CO3) (Formula C5). Furthermore, carbonic acid (H2CO3) reacts with Mg(OH)2 to form Mg(HCO3)2, which is a water-soluble Mg species (Formula C6). Accordingly, precursor composite particles (MgO-C composite), immersed in water, may be etched by CO2 (H2CO3), forming Mg(HCO3)2 (Formula C7). Another reaction may be carried out to degas (i.e., extract CO2 from) the water-soluble Mg species (Mg(HCO3)2) by boiling to form water-insoluble Mg(COs) in solid form (Formula C7). The Mg(COs) decarboxylates upon heating to about 350 °C (or higher), forming MgO (Formulas Cl and C2). As shown in Formula Al, MgO can be converted to magnesium citrate for use in subsequent pyrolysis.

[0120] Etching trials were conducted with respective acids on a common sample of precursor composite particles (MgO-C composite) and the BET specific surface areas and the total pore volumes were measured for each sample of porous carbon particles. The results are tabulated in Table 2 (FIG. 13). In the data reported in Table 2, the following etchants were used: CO2 (H2CO3 when dissolved in water), sulfuric acid (H2SO4), hydrochloric acid (HC1), citric acid, and acetic acid. The measured BET specific surface areas were in a range of about 2122 to 2176 m2 / g and the total pore volumes (TPVs) were in a range of about 1.30 to about 1.39 cm3 / g. Notably, etching by the weaker acids (e.g., citric acid, acetic acid) resulted in higher BET specific surface areas and higher total pore volumes than did etching by the stronger acids (e.g., sulfuric acid, hydrochloric acid).

[0121] In some designs, it may be advantageous for the Mg-based salt of organic acids (e.g., Mg citrate) or their various hydrated forms to be amorphous rather than crystalline. Amorphous and crystalline forms of a material may be distinguished by evaluating the material’s x-ray diffraction (XRD) patterns. Herein, a material that lacks well-defineddiffraction peaks and only exhibits diffuse “halos” in its XRD patterns is sometimes referred to as being “x-ray amorphous.” Herein, the term “amorphous” is used to refer to materials that are x-ray amorphous. For example, the amorphous structure of such a precursor may enable more uniform shrinkage (and may reduce or prevent formation of large cracks or undesirably large pores within porous carbon - MgO composite particles) during pyrolysis. In another example, the amorphous structure of such a precursor may also help make such precursor particles more rounded (including approximately spheroidal) and with controlled particle size distribution, which may result in the formation of rounded (including approximately spheroidal) porous carbon - MgO composite particles with tuned particle size distribution, then rounded (including approximately spheroidal) porous carbon particles and then eventually rounded (including approximately spheroidal) porous Si-C nanocomposite anode particles with the desired particle size distribution. The rounded (including approximately spheroidal) shape of such particles may enable their better packing density and improved mechanical properties, resulting in superior anode volumetric capacity, superior mechanical stability and superior electrochemical behavior in Li-ion battery cells.

[0122] In some designs, it may be advantageous to produce granules out of the metalorganic salt composition particles (e.g., magnesium citrate salt or its derivatives in the desired hydrated states) prior to processing those further to produce, for example, Si- C nanocomposite anode material particles. Granules may be much easier and safer to handle in various large synthesis reactors, such as rotary kiln reactors, packed bed reactors, fluidized bed reactors and others. In some designs, such granules (which may be called pellets) may preferably exhibit average characteristic dimensions D50) in the range from about 1 mm to about 10 mm (and exhibit an average volume from about 1 mm3to about 1000 mm3). Too small granules may be harder to handle, and too large granules may suffer from diffusion (mass transport) limitations during various synthesis steps and thus require longer (and thus more expensive) synthesis time. In some designs, it may be advantageous to have a relatively uniform size, uniform density and uniform shape of such granules. For example, in some designs, it may be advantageous for the span ( D90 - Dio) / Dso) of the granule sizes to be in the range from about 0.00000 to about 3.00000 (in some designs, from about 0.00000 to about 1.00000; in yet other designs, from about 0.00000 to about 0.50000; in yet other designs, from about 0.00000 to about 0.25000). Similarly, in some designs, it may be advantageous for the span of the density distributionof such granules (top 10% density minus bottom 10% density divided by an average density) to be in the range from range from about 0.00000 to about 0.20000 (in some designs, from about 0.00000 to about 0.10000; in yet other designs, from about 0.00000 to about 0.05000; in yet other designs, from about 0.00000 to about 0.01000). In some designs, the granules (pellets) may be cylindrical in shape or be tablet-shaped or be approximately spheroidal or approximately ellipsoidal or faceted. In some designs, it may be preferable for the granules to comprise little to no cracks and remain largely intact during battery material processing (e.g., generating less than about 10%, preferably less than about 1% fines before intentional milling).

[0123] Illustrative examples of suitable methods to produce granules include: (i) agitation, (ii) globulation, (iii) layering, (iv) compaction. Granulation methods may be dry or wet. Dry granulation may be achieved, for example, through roller compaction, or slugging. Dry granulation may have a binder pre-disposed onto the surface of primary particles or pre-mixed with the primary particles. Wet granulation may involve wetting the primary powder or powder mixture with a solvent or a binder solution and passing it through a screen of the mesh size needed to produce granules in the desired size using pressure and dry heat. Wet granulation may also use a fluid bed processor, drum roller, pin mixer or high shear mixer in which particles are placed and vigorously dispersed and suspended while liquid (which may comprise a binder) is sprayed onto the particles and dried (i.e. agitation or layering). Wet granulation may utilize press extruders, granulators, pellet pressers, pellet mills, briquetters, roll compactors, spray dryers and other suitable tools. It may be preferred to use water as a solvent for the wet granulation process. In some designs, wet granulation may be preferred. In some designs, compacting the powder and optional solvent and binder(s) to improve granule strength might be preferred.

[0124] FIG. 14 illustrates an example of a suitable process for the formation of Si-C particles with the desired particle size distribution according to some of the embodiments of the present disclosure. In step 1401 primary metalorganic salt composition particles (e.g., magnesium citrate salt or its derivatives in the desired hydrated states) with the the desired morphology (e.g., spheroidal, jagged, or irregularly shaped, etc.), size distribution (e.g., with D50 in the range from about 0.5 pm to about 30 pm in some examples) and microstructure (e.g., amorphous or nanocrystalline or poly crystalline) are produced or provided. In step 1402 such particles are mixed with a suitable binder solution (or a liquid with no binder, in some designs). In some designs (e.g., when particles could be fusedtogether during heating) no binder or no solvent may be needed. In step 1403 such particles or particles-binder mixture are processed into granules or pellets of suitable density (e.g., with remaining pores in the range of about 0.1 vol. % - about 75 vol. %; in some designs, in the range of about 10-50 vol. %), uniformity, shape and size. In step 1404 such granules are pyrolyzed under suitable conditions (e.g., relatively inert environment; controlled heating rate; maximum temperature in the range from about 500 °C to about 2000 °C; in some designs, from about 600 °C to about 1500 °C; in some designs, from about 700 °C to about 1100 °C) to make, for example, porous carbon-MgO composite granules (pellets) and preferably avoid pulverization or formation of large cracks or major defects that would significantly weaken granules’ mechanical properties. In step 1405 MgO or other (e.g., oxide) impurities are removed (e.g., by dissolution in a mild acid solution and washing or by other means) to produce porous carbon granules comprising linked (e.g., fused) primary porous carbon particles (e.g., sufficiently mechanically / structurally stable to survive some of the next steps without breaking and generating significant amount (e.g., > about 10 wt. %) of fines). In step 1406 the porous carbon granules are infiltrated with silicon (e.g., by using a chemical vapor deposition - for example, by using a silane (SiEU) gas as a silicon precursor or by other means) producing porous silicon-carbon composite granules. In some designs, such granules would comprise silicon (Si) in the form of nanoparticles infiltrated into carbon pores. In some designs, such Si nanoparticles exhibit volume-average D50 size in the range from about 1 nm to about 100 nm (in some designs, from about 2 to about 30 nm), as determined by TEM, SEM, SAXS, XRD or other suitable techniques or their combinations. In some designs, Si may be amorphous or exhibit average grain size below about 2 nm (in some designs, below about 1.5 nm; in some designs, below about 1 nm). In step 1407 at least a portion (or most) of the small pores remaining within the primary silicon-carbon composite particles are sealed by carbon or another suitable material by suitable means (e.g., by CVD of a hydrocarbon gas, for example, acetylene, propylene, ethane, etc. in case of the formation of a carbon coating) to protect Si surface against oxidation or other side reactions and to reduce BET specific surface area (SSA) of the granules below a desired value (e.g., in some design, below about 200 m2 / g; in other designs, below about 20 m2 / g; in other designs, below about 10 m2 / g; in other designs, below about 5 m2 / g; in other designs, below about 2 m2 / g). This process may result in the formation of closed pores (e.g., closed micropores or mesopores) within silicon-carbonparticles. In step 1408 the produced silicon-carbon composite granules are comminuted (milled) by suitable means (e.g., by jet mill) to attain a desired D50 of the particles (often correlated closely to the D50 of the initial (primary) metalorganic salt composition particles. In some designs, a portion of the comminuted particles (e.g., too small, such as fines or too large, such as chunks) are removed to attain the desired particle size distribution. Because this step may undesirably increase the BET SSA of the particles and may induce undesirable damages to the protective coating, additional (optional) step 1409 may comprise deposition of additional protective coating of carbon or another suitable material by suitable means (e.g., by CVD of a hydrocarbon gas, for example, acetylene, propylene, ethane, etc. in case of the formation of a carbon coating) to produce siliconcarbon composite particles with BET SSA in the desired range (e.g., in some designs, from about 0.2 to about 20 m2 / g; in other designs, from about 0.2 to about 2 m2 / g; in other designs, from about 2 to about 5 m2 / g; in other designs, from about 5 to about 10 m2 / g; in yet other designs, from about 10 to about 20 m2 / g).

[0125] FIG. 15 illustrates an example of granules produced from Mg citrate particles by an extrusion process: Mg citrate granules with no binder (1501), pyrolyzed Mg citrate granules comprising no binder (1502); pyrolyzed Mg citrate granules comprising 1 wt. % methyl cellulose binder (1503); pyrolyzed Mg citrate granules comprising 4 wt. % methyl cellulose binder (1504).

[0126] FIG. 16 illustrates examples of uniform tablet-shaped (cylindrical) granules produced from Mg citrate particles mixed with a binder (70 wt. % Mg citrate and 30 wt. % binder (20 wt. % poly(lauryl methacrylate) (PLMA) and lOwt. % polyethylene glycol (PEG)) using a tablet press: Mg citrate comprising granules (pellets) (1601); porous carbon granules produced by (i) pyrolysis of Mg citrate granules followed by (ii) removing majority of MgO using acetic acid aqueous solution (1602).

[0127] FIG. 17 illustrates examples of irregularly-shaped granules produced from Mg citrate particles mixed with a binder (70 wt. % Mg citrate and 30 wt. % binder (20 wt. % poly(lauryl methacrylate) (PLMA) and lOwt. % polyethylene glycol (PEG)) using a tablet press followed by breaking and sieving to make 2-3.5 mm granules: Mg citrate comprising granules (1701); porous carbon granules produced by (i) pyrolysis of Mg citrate granules followed by (ii) removing majority of MgO using acetic acid aqueous solution (1702).

[0128] FIG. 18 illustrates an example of SEM images of primary porous C-MgO composite particles produced by pyrolysis of Mg citrate particles (1801) and an example SEM image of the cross-section of pyrolyzed Mg citrate particles after MgO dissolution and removal (cross-section of porous carbon particles with less than 1 wt. % of MgO remaining).

[0129] For some applications, an ability to comminute (mill) granules by suitable means to attain a desired D50 of the particles is very important. FIG. 19 illustrates an example of the particle size distribution (1900) of porous carbon particles obtained by comminution of porous carbon granules using different parameter settings on a laboratory scale j et mill - Picoline (by Hosokawa), thus demonstrating ability to degranulate particles and attain particle size distribution close to that of the original primary particles. In one example, the granules were milled using a Picoline platform from Hosokawa equipped with a Picojet attachment. Nitrogen was used as a gas and the pressure was set up to 2 bars. The classifier wheel was adjusted and speed set up to 10000 rpm. The rinsing gas was set to 0 Nm3 / h. Granules were fed into the mill using the screw feeder at a 12% feed rate. Blower was set to auto and adjusted to -10 mbar + / -2 mbar during the run. The mill was turned off and powder was harvested from the filter bag.

[0130] In addition to a jet mill approach, other comminution techniques may be employed. In one example, 2g of granules were introduced into a 1-inch diameter x 3.5- inch height quartz vial with a cap that contained a 1 / 2 in. diameter steel rod. The vial was sealed and rolled at 0.3 m / s for 4 hours. The powder was recovered from the vial. An optional sifting step using a HK8 vibratory screener with ultrasonic deblinding system was performed (15 pm e-formed sieve, 60 Hz vibration, 25% sonicator power, 0.5 s / 0.5 s on / off cycling, 30 minute run time) (the deblinding system removes particles from a screen that is clogged with particles).

[0131] FIG. 20 illustrates some of the binders 2000 that may be advantageously used for the formation of granules.

[0132] It may be important for the granule binders to produce sufficient (e.g., > about 5 wt. %) carbon yield that would help link primary particles together during pyrolysis of metalorganic salt composition particles (e.g., magnesium citrate salt or its derivatives).

[0133] FIGS. 21-23 illustrate carbon yields 2100, 2200 and 2300, respectively, in the range from about 5 to about 38 wt. % attained by heating different candidate binder materials in an inert environment to about 900 °C at lOC / min (50mL / min Ar, 150pLalumina crucible, empty alumina crucible was used to blank the method). Prior to thermogravimetric analysis (TGA) experiments, the binder materials were dried at 80 °C in vacuum (e.g., for approximately 5-7 hours).Working Examples

[0134] Example 1 : The synthesis of the porous carbon particles reported in FIG. 8 A is as follows. Approximately 30 g of commercially-available Mg citrate tribasic nonahydrate was loaded into a 300 mm x 60 mm x 28 mm (LxWxH) quartz crucible and pyrolyzed by heating under flowing, dry N2 from room temperature to 900 °C with a ramp rate of 1 °C / min. Material was held at 900 °C for 30 min before cooling to room temperature. After cooling to room temperature, MgO was removed from the resulting C / MgO composite by mixing in a 3 M aqueous solution of H2SO4 for 1 h, followed by separation and washing by vacuum filtration. Separated material was further dried (100 °C under vacuum for at least 12 h). The dried material was further heat-treated at 1450 °C for 6 h (5 °C / min ramp to 250 °C, 10 °C / min ramp to 1250 °C, 5 °C / min ramp to 1450 °C).

[0135] Example 2: The synthesis of the porous carbon particles reported in FIG. 8B is as follows. Mg citrate particle synthesis: MgO powder was first dispersed in ethanol. Citric acid is then added to the MgO - ethanol mixture at a 3 :2 MgO:citric acid molar ratio and stirred for 24-72 hours, until a solid product (Mg citrate) was formed. This material was collected and dried under vacuum. Approximately 2 g of the dried material was then loaded into a 100 mm x 35 mm x 15 mm (LxWxH) quartz crucible and pyrolyzed by heating under flowing N2 to 900 °C at a rate of 15 °C / min. Material was held at 900 °C for 30 min before cooling to room temperature. MgO was then removed from the resulting MgO / C composite by wetting the powder with glacial acetic acid, then diluting with water to 2-5 wt. % acetic acid. The material was dispersed by manual mixing, then left at room temperature for at least 12 hours. The solid material was separated from the solution by centrifugation then washed 3 times with water, where in each wash cycle, the powder was redispersed in water and separated by centrifugation. The powder was then dried by heating to 60 °C under ambient atmosphere.

[0136] Example 3: The synthesis of the porous carbon particles reported in FIG. 9 is as follows. Between 20 and 60 g of commercially-available Mg citrate tribasic nonahydrate was loaded into a 300 mm x 60 mm x 28 mm (LxWxH) quartz crucible andpyrolyzed by heating under flowing, dry N2 from room temperature to 900 °C with ramp rates ranging from 5 °C / min to 15 °C / min. Material was held at 900 °C for 30 min before cooling to room temperature. It was found that MgO weight % increased with both increasing input mass loading and increasing temperature ramp rate. After cooling to room temperature, MgO was removed from the resulting C / MgO composite by mixing in a 3 M aqueous solution of H2SO4 for 1 h, followed by separation and washing by vacuum filtration. Separated material was further dried (100 °C under vacuum for at least 12 h). The dried material was further heat-treated at 1450 °C for 6 h (5 °C / min ramp to 250 °C, 10 °C / min ramp to 1250 °C, 5 °C / min ramp to 1450 °C). MgO weight % was determined by a thermogravimetric analysis (TGA) method. For this method, material was loaded into an alumina crucible and heated in a thermogravimetric analyzer under Ar from 30 °C to 1000 °C at a 10 °C / min ramp rate, then held at 1000 °C for 20 min. Ar flow was then halted, and dry air was flowed over the sample for 1 h at 1000 °C. The weight % MgO was then calculated as (m2 / mi) xlOO, where mi is the sample mass at 1000 °C prior to starting the air flow and m2 is the sample mass after 1 h hold in air at 1000 °C.

[0137] Example 4: The synthesis of the porous carbon particles reported in FIG. 10A is as follows. To vary the acetate content (x) in the hybrid salt system Mg3Cit2-xAc3x, MgAc2 was first dissolved in water by stirring to form a clear solution. A stoichiometric amount of citric acid (2-x moles per 3 moles of Mg) was then added to the solution and dissolved by stirring. The solution was then stirred for 1 hour to enable reaction completion. Water and byproduct acetic acid were then evaporated by heating the stirring solution between 75-125 °C, until a dry product was obtained. This material was then pyrolyzed by heating under flowing dry N2 from room temperature to 900 °C with a ramp rate of 5 °C / min. Material was held at 900 °C for 30 min before cooling to room temperature. After cooling to room temperature, MgO was removed from the resulting C / MgO composite by dispersing in a 3 M aqueous solution of H2SO4 and allowing material to sit for at least 12 h. The material was then separated and washed by vacuum filtration. Separated and washed material was dried at 125 °C under ambient atmosphere until visibly dry, then further dried at 100 °C under vacuum for at least 3 hours. The dried material was further heat-treated at 1450 °C for 6 h (5 °C / min ramp to 250 °C, 10 °C / min ramp to 1250 °C, 5 °C / min ramp to 1450 °C).

[0138] Example 5: The synthesis of the porous carbon particles used in the lithium- ion battery test cells reported in FIG. 11 is as follows. MgAc2 was first dissolved in waterby stirring to form a clear solution. A stoichiometric amount of citric acid (2 moles citric acid per 3 moles of Mg) was then added to the solution and dissolved by stirring. The solution was then stirred for 1 hour to enable reaction completion. Water and byproduct acetic acid were then evaporated by heating the stirring solution between 75-125 °C, until a dry product was obtained. This material was then pyrolyzed by heating under flowing dry N2 from room temperature to 900 °C with a ramp rate of 5 °C / min. Material was held at 900 °C for 30 min before cooling to room temperature. After cooling to room temperature, MgO was removed from the resulting C / MgO composite by dispersing in a 3 M aqueous solution of H2SO4 and allowing material to sit for at least 12 h. The material was then separated and washed by vacuum filtration. Separated and washed material was dried at 125 °C under ambient atmosphere until visibly dry, then further dried at 100 °C under vacuum for at least 3 hours. The dried material was further heat-treated at 1450 °C for 6 h (5 °C / min ramp to 250 °C, 10 °C / min ramp to 1250 °C, 5 °C / min ramp to 1450 °C). Si infiltration, C sealing, and comminution operations were then carried out as described herein.

[0139] Example 6: The fabrication and testing of the lithium-ion battery test cells reported in FIG. 11 is as follows. Li-ion battery cells were produced using: (i) anodes with about 62-65 % of capacity contributed by Si-C nanocomposite active material (e.g., particles) and about 35-38% of capacity contributed by graphite (with specific reversible Si-C nanocomposite capacity of about 1640 to about 1690 mAh / g when normalized by the weight of Si-C nanocomposite, which corresponds to about 51 to about 53 wt. % of silicon mass fraction in Si-C composite particles), respectively, cast on Cu current collector foil from a water-based suspension comprising the following solids: about 95.2 wt. % of active materials (for the anodes with the about 62-65 % of capacity contributed by Si-C nanocomposite active material and the rest contributed by graphite), a carboxymethylcellulose / styrene-butadiene rubber (CMC / SBR) binder (about 1.7 wt. % CMC, 3 wt. % SBR), and about 0.1 wt. % Tuball carbon nanotube conductive additive dispersion, (ii) a cathode comprising about 94 wt. % LiNio.8Coo.1Mno.1O2 (NCM-811) active material (with specific reversible capacity of about 200 mAh / g when normalized by the weight of NCM-811 active materials in the cathode) cast on Al current collector foil from an organic solvent suspension comprising a PVDF - based binder (about 2 wt. %) and Super P carbon black (about 4 wt. %) conductive additive, matched with the anode at anode:cathode (negative-to-positive, NP) areal capacity ratio of about 1.1 : 1 andareal reversible capacity loading of about 3.8 mAh / cm2, (iii) a polymer-ceramic separator, and (iv) an LiPFe-based electrolyte comprising: about 13.92 wt. % LiPFe, about 13.33 wt. % fluoroethylene carbonate (FEC, fluorinated cyclic carbonate), about 3.85 wt. % ethyl methyl carbonate (EMC, linear carbonate), about 5.04 wt. % ethylene carbonate (EC, cyclic carbonate), about 62.49 wt. % dimethyl carbonate (DMC, linear carbonate), about 0.85 wt. % lithium difluorophosphate, and about 0.52 wt. % vinylene carbonate (VC, cyclic carbonate). All electrochemical (ECT) tests were performed using Arbin Instruments LBT battery cyclers, running MITS X PRO software. Cycling was obtained using a voltage range of 2.5-4.2V at a 1C charge (with voltage hold to 0.05 C) and 1C discharge, with capacity check cycles using a 0.5 C charge to 4.2 V, then a voltage hold to 0.05 C, followed by a 0.2 C discharge. Si-C nanocomposite particles with D50 values in a range of 5 to 8 pm were used. In the foregoing example Li-ion battery cells in which Si-C nanocomposite active material contributed about 65 % of the capacity, about 75 wt. % of the anode active material was graphite particles and about 25 wt. % of the anode active material was Si-C nanocomposite active material particles.

[0140] Example 7: The synthesis of the porous carbon particles reported in FIG. 13 (Table 2) is as follows. Approximately 30 g of commercially-available Mg citrate tribasic nonahydrate was loaded into a 300 mm x 60 mm x 28 mm (LxWxH) quartz crucible and pyrolyzed by heating under flowing, dry N2 from room temperature to 900 °C with a ramp rate of 5 °C / min. Material was held at 900 °C for 30 min before cooling to room temperature. For MgO removal with hydrochloric, sulfuric, citric, and acetic acids: pyrolyzed material was added to deionized water in a reaction vessel. 3N acid solution was added slowly to the powder-water mixture while stirring. The amount of acid added was approximately 2.2 molar equivalents per MgO. The powder-acid mixture was stirred for at least 2 hours, then filtered and washed with additional 3N acid, followed by multiple washes with DI water. Solids were collected from the filter and dried under vacuum. For MgO removal with carbonic acid, pyrolyzed material was added to deionized water in a reaction vessel. The solution was sparged with CO2 gas while stirring. The solution pH was monitored through, and when pH had equilibrated, solids were collected via filtration. The sparging / filter process with solids was repeated until MgO removal was complete. Solids were then dried under vacuum.

[0141] Some embodiments of the present disclosure on Li-ion batteries comprising anodes with magnesium organic salt composition-derived particles maybenefit from the use of certain electrolyte compositions in battery cell fabrication to attain superior characteristics. In some designs, suitable electrolyte composition may comprise (i) one, two, three or more Li salts with the total concentration in the range from about 0.8M to about 2.0 M (in some designs, from about 0.8M to about 1.0M; in other designs, from about IM to about 1.1M; in other designs, from about 1.1M to about 1.2M; in other designs, from about 1.2M to about 1.3M; in other designs, from about 1.3M to about 1.4M; in other designs, from about 1.4M to about 1.6M; in other designs, from about 1.6M to about 1.7M; in other designs, from about 1.7M to about 1.8M; in other designs, from about 1.8M to about 2.0 M); (ii) one, two or more cyclic carbonates (in some designs, fluorinated cyclic carbonates, such as FEC, among others), (iii) zero, one, two, three or more nitrogen-comprising co-solvents (in some designs, at least some of the nitrogen comprising co-solvents may advantageously comprise two or three or more nitrogen atoms per molecules), (iv) zero, one, two, three or more sulfur comprising cosolvents, (v) zero, one, two, three or more phosphorous comprising co-solvents (note that some co-solvents may advantageously comprise both phosphorus and sulfur), (vi) zero, one, two, three or more linear or branched esters as co-solvents, (vii) zero, one, two, or more linear carbonates as co-solvents, (viii) zero, one, two, three or more additional electrolyte co-solvents or additives, or (ix) any combination thereof. In some designs, the volume fraction of linear esters (as a fraction of all co-solvents in the electrolyte) may range from about 20 vol. % to about 85 vol. % (in some designs, from about 20 vol. % to about 40 vol. %; in other designs, from about 40 vol. % to about 60 vol. %; in yet other designs, from about 60 vol. % to about 85 vol. %). In some designs, the volume fraction of branched esters (as a fraction of all co-solvents in the electrolyte) may range from about 10 vol. % to about 80 vol. % (in some designs, from about 10 vol. % to about 30 vol. %; in other designs, from about 30 vol. % to about 60 vol. %; in yet other designs, from about 60 vol. % to about 80 vol. %). In some designs, the volume fraction of cyclic carbonates (as a fraction of all co-solvents in the electrolyte) may range from about 5 vol. % to about 40 vol. % (in some designs, from about 5 vol. % to about 10 vol. %; in other designs, from about 10 vol. % to about 20 vol. %; in yet other designs, from about 20 vol. % to about 40 vol. %). In some designs, the volume fraction of fluorinated cyclic carbonates (as a fraction of all co-solvents in the electrolyte) may range from about 1 vol. % to about 20 vol. % (in some designs, from about 1 vol. % to about 4 vol. %; in other designs, from about 4 vol. % to about 6 vol. %; in other designs, from about 6 vol. % to about 12 vol. %;in yet other designs, from about 12 vol. % to about 20 vol. %). In some designs, the volume fraction of vinylene carbonate (VC) (as a fraction of all co-solvents in the electrolyte) may range from about 0.25 vol. % to about 6 vol. % (in some designs, from about 0.25 vol. % to about 0.5 vol. %; in other designs, from about 0.5 vol. % to about 1 vol. %; in other designs, from about 1 vol. % to about 2 vol. %; in yet other designs, from about 2 vol. % to about 6 vol. %). In some designs, about 50 vol. % or more of the cosolvents may advantageously exhibit a melting point below about minus (-) 60 °C (in some designs, below about - 70°C; in other designs, below about - 80°C). In some designs utilizing two or more salts (e.g., two salts or three salts or four salts or five salts, etc.), it may be advantageous for at least one of the salts to comprise LiPFe. In some designs, the incorporation of such salts may enhance properties (e.g., cycle stability, resistance, thermal stability, performance at high or low temperatures, etc.) of the cathode electrolyte interphase (CEI) layer or the anode solid electrolyte interface (SEI) layer or provide other performance advantages. In some designs, it may be further advantageous for at least one other salt to also be a salt of Li. Examples of some of such suitable salts include, but are not limited to: LiFSI, LiTFSI, LiBETI and / or other Li imide salts, Li bis(oxalato)borate (LiBOB), Li difluoro(oxalato)borate (LiDFOB), Li 2-trifluoromethyl- 4,5-dicyanoimidazolide (LiTDi), Li 4,5-dicyano-2-(pentafluoroethyl) imidazolide (LiPDi), Li difluorophosphate (LiDFP), Li nitrate (LiNCL), etc.).

[0142] In the detailed description above it can be seen that different features are grouped together in examples. This manner of disclosure should not be understood as an intention that the example clauses have more features than are explicitly mentioned in each clause. Rather, the various aspects of the disclosure may include fewer than all features of an individual example clause disclosed. Therefore, the following clauses should hereby be deemed to be incorporated in the description, wherein each clause by itself can stand as a separate example. Although each dependent clause can refer in the clauses to a specific combination with one of the other clauses, the aspect(s) of that dependent clause are not limited to the specific combination. It will be appreciated that other example clauses can also include a combination of the dependent clause aspect(s) with the subject matter of any other dependent clause or independent clause or a combination of any feature with other dependent and independent clauses. The various aspects disclosed herein expressly include these combinations, unless it is explicitly expressed or can be readily inferred that a specific combination is not intended (e.g.,contradictory aspects, such as defining an element as both an electrical insulator and an electrical conductor). Furthermore, it is also intended that aspects of a clause can be included in any other independent clause, even if the clause is not directly dependent on the independent clause.

[0143] Implementation examples are described in the following numbered clauses:

[0144] Clause 1. A method of making porous carbon particles, the method comprising: (Al) making a solution comprising a magnesium organic salt composition; (A2) precipitating particles of the magnesium organic salt composition from the solution; (A3) pyrolyzing the particles of the magnesium organic salt composition to form precursor composite particles comprising carbon and at least one magnesium compound; and (A4) selectively removing the magnesium compound from the precursor composite particles to convert the precursor composite particles to the porous carbon particles, wherein: the at least one magnesium compound comprises MgO.

[0145] Clause 2. The method of clause 1, wherein: magnesium organic salt composition comprises a higher carbon-yielding magnesium organic salt and a lower carbon-yielding magnesium organic salt.

[0146] Clause 3. The method of clause 2, wherein: the higher carbon-yielding magnesium organic salt comprises magnesium citrate.

[0147] Clause 4. The method of any of clauses 2 to 3, wherein: the lower carbon- yielding magnesium organic salt comprises magnesium acetate.

[0148] Clause 5. The method of any of clauses 1 to 4, wherein: the magnesium organic salt composition comprises citrate ligands.

[0149] Clause 6. The method of clause 5, wherein: the magnesium organic salt composition comprises acetate ligands.

[0150] Clause 7. The method of clause 6, wherein: a mass fraction of the acetate ligands in a sum of the acetate and the citrate ligands is in a range of about 22 to about 66 wt. %.

[0151] Clause 8. The method of clause 7, wherein: the mass fraction is in a range of about 25 to about 61 wt. %.

[0152] Clause 9. The method of any of clauses 6 to 8, wherein: the making (Al) comprises (a) making a first solution of the Mg acetate and (b) mixing citric acid with the first solution to obtain the solution.

[0153] Clause 10. The method of any of clauses 1 to 9, wherein: the precipitating (A2) comprises vaporizing the water.

[0154] Clause 11. The method of any of clauses 1 to 10, wherein: the pyrolyzing (A3) is carried out in a temperature range of about 750 to about 1200 °C in an inert atmosphere.

[0155] Clause 12. The method of clause 11, wherein: the pyrolyzing (A3) is carried out in a temperature range of about 850 to about 950 °C and the inert atmosphere comprises N2.

[0156] Clause 13. The method of any of clauses 1 to 12, wherein: the selectively removing (A4) comprises etching by an acid.

[0157] Clause 14. The method of clause 13, wherein: the acid comprises sulfuric acid, hydrochloric acid, citric acid, acetic acid, and / or carbonic acid.

[0158] Clause 15. The method of any of clauses 1 to 14, wherein: the precursor composite particles are characterized by an average precursor composite particle size of at least about 0.1 mm.

[0159] Clause 16. The method of any of clauses 1 to 15, wherein: the porous carbon particles are characterized by an average porous carbon particle size of at least about 0.1 mm.

[0160] Clause 17. The method of any of clauses 1 to 16, wherein: the porous carbon particles are characterized by a Brunauer-Emmett-Teller (BET) specific surface area (SSA) in a range of about 1000 to about 3500 m2 / g.

[0161] Clause 18. The method of clause 17, wherein: the BET SSA is in a range of about 1800 to about 3500 m2 / g.

[0162] Clause 19. The method of any of clauses 1 to 18, wherein: the porous carbon particles are characterized by a total pore volume (TPV) in a range of about 1.2 to about 2.5 cm3 / g.

[0163] Clause 20. The method of clause 19, wherein: the TPV is in a range of about 1.8 to about 2.2 cm3 / g.

[0164] Clause 21. The porous carbon particles made according to the method of any of clauses 1 to 20.

[0165] Clause 22. A method of making silicon-carbon composite particles, the method comprising: (Bl) making the porous carbon particles according to the method of any of clauses 1 to 20; (B2) forming a silicon material on and / or in the porous carbonparticles to form the silicon-carbon composite particles; and (B3) forming a protective material on and / or in the silicon-carbon composite particles.

[0166] Clause 23. The method of clause 22, wherein: the protective material comprises carbon or an oxide.

[0167] Clause 24. The method of clause 22, wherein: the particles of the magnesium organic salt composition are formed into granules prior to pyrolysis;

[0168] Clause 25. The method of clause 24, wherein: the porous carbon granules are formed by annealing granules comprising magnesium organic salt composition particles and removing MgO by dissolution or other means;

[0169] Clause 26. The method of clause 25, wherein: silicon is formed on and / or in the granulated porous carbon particles;

[0170] Clause 27. The method of clause 26, wherein: a protective (e.g., carbon) material is deposited on and / or in the granulated silicon-carbon composite particles.

[0171] Clause 28. The method of clause 27, wherein: silicon-carbon composite particles of the suitable particle size distribution and composition are obtained by comminuting (milling) of granulated silicon-carbon composite particles and optionally depositing an additional protective coating.

[0172] Clause 29. The silicon-carbon composite particles made according to the method of any of clauses 22 to 28.

[0173] Clause 30. A Li-ion rechargeable battery, comprising: an anode comprising the silicon-carbon composite particles of clause 29; a cathode; and a separator ionically coupling the anode and the cathode.

[0174] Implementation examples are described in the following numbered Additional Clauses:

[0175] Additional Clause 1 : A method of making porous carbon particles, the method comprising: (Al) making a solution comprising a magnesium organic salt composition; (A2) precipitating particles of the magnesium organic salt composition from the solution; (A3) pyrolyzing the particles of the magnesium organic salt composition to form precursor composite particles comprising carbon and at least one magnesium compound; and (A4) selectively removing the at least one magnesium compound from the precursor composite particles to convert the precursor composite particles to the porous carbon particles, wherein: the at least one magnesium compound comprises MgO.

[0176] Additional Clause 2: The method of Additional Clause 1, wherein: the magnesium organic salt composition comprises a higher carbon-yielding magnesium organic salt and a lower carbon-yielding magnesium organic salt.

[0177] Additional Clause 3 : The method of any of Additional Clauses 1 to 2, wherein: the higher carbon-yielding magnesium organic salt comprises magnesium citrate.

[0178] Additional Clause 4: The method of any of Additional Clauses 1 to 3, wherein: the lower carbon-yielding magnesium organic salt comprises magnesium acetate.

[0179] Additional Clause 5: The method of any of Additional Clauses 1 to 4, wherein: the making (Al) comprises (a) making a first solution of the magnesium acetate and (b) mixing citric acid with the first solution to obtain the solution.

[0180] Additional Clause 6: The method of any of Additional Clauses 1 to 5, wherein: the magnesium organic salt composition comprises citrate ligands.

[0181] Additional Clause 7: The method of any of Additional Clauses 1 to 6, wherein: the magnesium organic salt composition comprises acetate ligands.

[0182] Additional Clause 8: The method of any of Additional Clauses 1 to 7, wherein: a mass fraction of the acetate ligands in a sum of the acetate and the citrate ligands is in a range of about 22 to about 66 wt. %.

[0183] Additional Clause 9: The method of any of Additional Clauses 1 to 8, wherein: the mass fraction is in a range of about 25 to about 61 wt. %.

[0184] Additional Clause 10: The method of any of Additional Clauses 1 to 9, wherein: the solution comprises a solvent comprising water; and the precipitating (A2) comprises vaporizing the water.

[0185] Additional Clause 11 : The method of any of Additional Clauses 1 to 10, wherein: the pyrolyzing (A3) is carried out in a temperature range of about 750 to about 1200 C in an inert atmosphere.

[0186] Additional Clause 12: The method of any of Additional Clauses 1 to 11, wherein: the pyrolyzing (A3) is carried out in a temperature range of about 850 to about 950 C and the inert atmosphere comprises N2.

[0187] Additional Clause 13: The method of any of Additional Clauses 1 to 12, wherein: the selectively removing (A4) comprises etching by an acid.

[0188] Additional Clause 14: The method of any of Additional Clauses 1 to 13, wherein: the acid comprises sulfuric acid, hydrochloric acid, citric acid, acetic acid, and / or carbonic acid.

[0189] Additional Clause 15: The method of any of Additional Clauses 1 to 14, wherein: the precursor composite particles are characterized by an average precursor composite particle size of at least about 0.1 mm.

[0190] Additional Clause 16: The method of any of Additional Clauses 1 to 15, wherein: the porous carbon particles are characterized by an average porous carbon particle size of at least about 0.1 mm.

[0191] Additional Clause 17: The method of any of Additional Clauses 1 to 16, wherein: the porous carbon particles are characterized by a Brunauer-Emmett-Teller (BET) specific surface area (SSA) in a range of about 1000 to about 3500 m2 / g.

[0192] Additional Clause 18: The method of any of Additional Clauses 1 to 17, wherein: the BET SSA is in a range of about 1800 to about 3500 m2 / g.

[0193] Additional Clause 19: The method of any of Additional Clauses 1 to 18, wherein: the porous carbon particles are characterized by a total pore volume (TPV) in a range of about 1.2 to about 2.5 cm3 / g upon completion of the selectively removing (A4) without any additional activation process.

[0194] Additional Clause 20: The method of any of Additional Clauses 1 to 19, wherein: the TPV is in a range of about 1.8 to about 2.2 cm3 / g.

[0195] Additional Clause 21 : The porous carbon particles made according to the method of any of Additional Clauses 1 to 20.

[0196] Additional Clause 22: The porous carbon particles of any of Additional Clauses 1 to 21, wherein the porous carbon particles are x-ray amorphous.

[0197] Additional Clause 23: A method of making silicon-carbon composite particles, the method comprising: (Bl) making the porous carbon particles according to the method of any of Additional Clauses 1 to 22; (B2) forming a silicon material on and / or in the porous carbon particles to form the silicon-carbon composite particles; and (B3) forming a protective material on and / or in the silicon-carbon composite particles.

[0198] Additional Clause 24: The method of any of Additional Clauses 1 to 23, wherein: the protective material comprises carbon and / or an oxide.

[0199] Additional Clause 25: The silicon-carbon composite particles made according to the method of any of Additional Clauses 1 to 24.

[0200] Additional Clause 26: A Li-ion rechargeable battery, comprising: an anode comprising the silicon-carbon composite particles of any of Additional Clauses 1 to 25; a cathode; and an electrolyte ionically coupling the anode and the cathode.

[0201] Additional Clause 27: A method of making silicon-carbon composite particles, the method comprising: (Cl) making primary magnesium organic salt composition particles; (C2) forming the primary magnesium organic salt composition particles into granules or pellets; (C3) pyrolyzing the granules or pellets to form granulated precursor composite particles comprising carbon and at least one magnesium compound, wherein: the at least one magnesium compound comprises MgO; (C4) selectively removing the at least one magnesium compound from the granulated precursor composite particles to convert the granulated precursor composite particles to porous carbon granules; (C5) forming a silicon material on and / or in the porous carbon granules to form silicon-carbon composite granules; (C6) forming a protective material on and / or in the silicon-carbon composite granules, wherein: the protective material comprises carbon and / or an oxide; and (C7) comminuting the silicon-carbon composite granules to obtain the silicon-carbon composite particles with a D50 from about 1 pm to about 20 pm.

[0202] Additional Clause 28: The method of Additional Clause 27, wherein the primary magnesium organic salt composition particles comprise magnesium citrate salt, or a derivative thereof in a hydrated state.

[0203] Additional Clause 29: The method of any of Additional Clauses 27 to 28, further comprising: (C8) forming an additional protective material on and / or in the silicon-carbon composite particles, wherein: the additional protective material comprises carbon and / or an oxide.

[0204] Additional Clause 30: Silicon-carbon composite particles made according to the method of any of Additional Clauses 27 to 29.

[0205] Additional Clause 31 : A Li-ion rechargeable battery, comprising: an anode comprising the silicon-carbon composite particles of any of Additional Clauses 27 to 30; a cathode; and an electrolyte ionically coupling the anode and the cathode.

[0206] This description is provided to enable any person skilled in the art to make or use embodiments of the present invention. It will be appreciated, however, that the present invention is not limited to the particular formulations, process steps, and materials disclosed herein, as various modifications to these embodiments will be readily apparent to those skilled in the art. That is, the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention.

Claims

CLAIMS1. A method of making porous carbon particles, the method comprising:(Al) making a solution comprising a magnesium organic salt composition;(A2) precipitating particles of the magnesium organic salt composition from the solution;(A3) pyrolyzing the particles of the magnesium organic salt composition to form precursor composite particles comprising carbon and at least one magnesium compound; and(A4) selectively removing the at least one magnesium compound from the precursor composite particles to convert the precursor composite particles to the porous carbon particles, wherein: the at least one magnesium compound comprises MgO.

2. The method of claim 1, wherein: the magnesium organic salt composition comprises a higher carbon-yielding magnesium organic salt and a lower carbon-yielding magnesium organic salt.

3. The method of claim 2, wherein: the higher carbon-yielding magnesium organic salt comprises magnesium citrate.

4. The method of claim 3, wherein: the lower carbon-yielding magnesium organic salt comprises magnesium acetate.

5. The method of claim 4, wherein: the making (Al) comprises (a) making a first solution of the magnesium acetate and (b) mixing citric acid with the first solution to obtain the solution.

6. The method of claim 1, wherein: the magnesium organic salt composition comprises citrate ligands.

7. The method of claim 6, wherein: the magnesium organic salt composition comprises acetate ligands.

8. The method of claim 7, wherein: a mass fraction of the acetate ligands in a sum of the acetate and the citrate ligands is in a range of about 22 to about 66 wt. %.

9. The method of claim 8, wherein: the mass fraction is in a range of about 25 to about 61 wt. %.

10. The method of claim 1, wherein: the solution comprises a solvent comprising water; and the precipitating (A2) comprises vaporizing the water.

11. The method of claim 1, wherein: the pyrolyzing (A3) is carried out in a temperature range of about 750 to about 1200 °C in an inert atmosphere.

12. The method of claim 11, wherein: the pyrolyzing (A3) is carried out in a temperature range of about 850 to about 950 °C and the inert atmosphere comprises N2.

13. The method of claim 1, wherein: the selectively removing (A4) comprises etching by an acid.

14. The method of claim 13, wherein: the acid comprises sulfuric acid, hydrochloric acid, citric acid, acetic acid, and / or carbonic acid.

15. The method of claim 1, wherein: the precursor composite particles are characterized by an average precursor composite particle size of at least about 0.1 mm.

16. The method of claim 1, wherein:the porous carbon particles are characterized by an average porous carbon particle size of at least about 0.1 mm.

17. The method of claim 1, wherein: the porous carbon particles are characterized by a Brunauer-Emmett-Teller (BET) specific surface area (SSA) in a range of about 1000 to about 3500 m2 / g.

18. The method of claim 17, wherein: the BET SSA is in a range of about 1800 to about 3500 m2 / g.

19. The method of claim 1, wherein: the porous carbon particles are characterized by a total pore volume (TPV) in a range of about 1.2 to about 2.5 cm3 / g upon completion of the selectively removing (A4) without any additional activation process.

20. The method of claim 19, wherein: the TPV is in a range of about 1.8 to about 2.2 cm3 / g.

21. The porous carbon particles made according to the method of claim 1.

22. The porous carbon particles of claim 21, wherein the porous carbon particles are x-ray amorphous.

23. A method of making silicon-carbon composite particles, the method comprising:(Bl) making the porous carbon particles according to the method of claim 1;(B2) forming a silicon material on and / or in the porous carbon particles to form the silicon-carbon composite particles; and(B3) forming a protective material on and / or in the silicon-carbon composite particles.

24. The method of claim 23, wherein: the protective material comprises carbon and / or an oxide.

25. The silicon-carbon composite particles made according to the method of claim 24.

26. A Li-ion rechargeable battery, comprising: an anode comprising the silicon-carbon composite particles of claim 25; a cathode; and an electrolyte ionically coupling the anode and the cathode.

27. A method of making silicon-carbon composite particles, the method comprising:(Cl) making primary magnesium organic salt composition particles;(C2) forming the primary magnesium organic salt composition particles into granules or pellets;(C3) pyrolyzing the granules or pellets to form granulated precursor composite particles comprising carbon and at least one magnesium compound, wherein: the at least one magnesium compound comprises MgO;(C4) selectively removing the at least one magnesium compound from the granulated precursor composite particles to convert the granulated precursor composite particles to porous carbon granules;(C5) forming a silicon material on and / or in the porous carbon granules to form silicon-carbon composite granules;(C6) forming a protective material on and / or in the silicon-carbon composite granules, wherein: the protective material comprises carbon and / or an oxide; and(C7) comminuting the silicon-carbon composite granules to obtain the siliconcarbon composite particles with a D50 from about 1 pm to about 20 pm.

28. The method of claim 27, wherein the primary magnesium organic salt composition particles comprise magnesium citrate salt, or a derivative thereof in a hydrated state.

29. The method of claim 27, further comprising:(C8) forming an additional protective material on and / or in the silicon-carbon composite particles, wherein: the additional protective material comprises carbon and / or an oxide.

30. Silicon-carbon composite particles made according to the method of claim 27.

31. A Li-ion rechargeable battery, comprising: an anode comprising the silicon-carbon composite particles of claim 30; a cathode; and an electrolyte ionically coupling the anode and the cathode.

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