Battery electrode composition containing biomass-derived carbon

Abstract

To provide an electrode composition for use in an energy storage device cell.SOLUTION: The electrode comprises composite particles, each comprising biomass-derived carbon and active material. The active material exhibits partial vapor pressure below about 10-13 torr at about 400 K. An areal capacity loading of the electrode composition ranges from about 2 mAh / cm2 to about 16 mAh / cm2.SELECTED DRAWING: Figure 2A

Description

[Technical Field]

[0001] Claiming priority under 35 U.S.C. § 119 This patent application claims the benefit of U.S. Provisional Patent Application No. 62 / 731,771, filed September 14, 2018, entitled "SUPERCAPACITOR AND BATTERY ELECTRODES COMPRISING BIOLOGICALLY DERIVABLE CARBON," which is expressly incorporated herein by reference in its entirety.

[0002] The present disclosure relates generally to energy storage devices, and more particularly to battery technology, supercapacitor technology, and the like. [Background technology]

[0003] Due in part to their relatively high energy density, relatively high specific energy, relatively high specific power, relatively fast charging, light weight, and potential for long life and cycle life, high performance rechargeable batteries and supercapacitors are desirable for a wide range of electronic devices, electric vehicles, grid storage, and other important applications.

[0004] However, despite the commercial adoption of electrochemical energy storage technologies, further development of batteries and supercapacitors is needed, particularly for potential applications in low- or zero-emission hybrid-electric or all-electric vehicles, home appliances, energy-efficient cargo ships and locomotives, space applications, and power grids. In particular, further improvements are desired for various rechargeable batteries, such as rechargeable metal and metal-ion batteries (such as rechargeable Li and Li-ion batteries, rechargeable Na and Na-ion batteries, rechargeable Mg and Mg-ion batteries, rechargeable K and K-ion batteries, rechargeable Ca and Ca-ion batteries, etc.). The following energy storage devices could similarly benefit from further improvements: rechargeable halogen-ion batteries (such as F-ion and Cl-ion batteries), rechargeable mixed-ion batteries, rechargeable aqueous batteries (e.g., rechargeable batteries with pH-neutral, acidic, or caustic electrolytes), electrochemical capacitors (e.g., supercapacitors or double layer capacitors), hybrid devices, rechargeable polymer electrolyte batteries and supercapacitors, rechargeable polymer gel electrolyte batteries and supercapacitors, rechargeable solid ceramic or solid glass electrolyte batteries, rechargeable composite electrolyte batteries, to name a few.

[0005] A wide range of active (charge storage) materials, a wide range of polymer binders, a wide range of conductive additives, and various mixing recipes can be used in the construction of battery electrodes. In some designs, the active material can be used in the form of composite particles. However, the optimal composite formulation needs to be identified to improve electrode performance (low and stable resistance, high cycling stability, high rate performance, acceptable energy, good volumetric capacity, etc.). Furthermore, the selection of binders, additives, and mixing protocols needs to be discovered for the specific type, physical and chemical properties, and size of active particles. In many cases, the selection of composite particle architecture and composition and electrode composition can be non-trivial and counter-intuitive.

[0006] In many different types of rechargeable batteries and supercapacitors, charge storage materials can be produced as (nano)composite powders that may contain conductive carbon. As a subset of such particles, conductive carbon can be biologically derived. In principle, such a class of charge storage (nano)composite particles could offer great promise for scalable (and potentially sustainable) manufacturing and achieving good charge storage performance characteristics. Unfortunately, it remains largely unclear what types and properties of biologically derived carbons would be advantageous for the application of such composite (nano)composite particles. Furthermore, it is even less clear how to effectively process such (nano)composite particles into electrodes that would result in good performance characteristics, including high capacity, fast charge / discharge rates, and long cycling stability. The performance of battery electrodes made from similar (nano)composites is expected to be higher than that of conventional (nano)composite electrodes, with moderate electrode capacity loadings (2-4 mAh / cm). 2 ) and becomes particularly worse when it becomes high (for example, 4 to 16 mAh / cm 2 ), which can be further deteriorated. On the other hand, higher capacity loading is advantageous for increasing the energy density of the battery cell and reducing the cell manufacturing cost. The performance of supercapacitor electrodes made from similar (nano)composites is comparable to that of supercapacitor electrodes with an electrode capacity loading of about 0.1 mAh / cm. 2 On the other hand, higher capacitance loading is advantageous for increasing the energy density of the supercapacitor and reducing the cell manufacturing cost.

[0007] Thus, there remains a need for improvements in batteries, components, electrode materials and other related materials and manufacturing processes. Summary of the Invention

[0008] The present embodiment is directed to an electrode composition for use in an energy storage device cell. The electrode includes composite particles, each of which includes biomass-derived carbon and an active material. The active material has a thermal conductivity of about 10 at about 400 K. -13 torr, and the areal capacity loading of the electrode composition is approximately 2 mAh / cm 2 ~About 16mAh / cm2 The range is.

[0009] The accompanying drawings are presented to aid in the description of embodiments of the present disclosure and are given solely for the purpose of illustrating the embodiments, not for the purpose of limiting them. Unless otherwise stated or implied in context, different hatching, shading, and / or fill patterns in the figures are meant only to illustrate contrasts between different components, elements, features, etc., and are not meant to convey the use of particular materials, colors, or other characteristics that may be specified outside this disclosure for the specific patterns employed. [Brief explanation of the drawings]

[0010] [Figure 1] 1 illustrates an exemplary (e.g., Li-ion) battery to which the components, materials, methods, and other techniques described herein, or combinations thereof, may be applied, according to various exemplary embodiments. [Figure 2A] 1 illustrates two exemplary processes for the formation of biomass-derived carbon-containing composite particles, according to various exemplary embodiments. [Figure 2B] 1 illustrates two exemplary processes for the formation of biomass-derived carbon-containing composite particles, according to various exemplary embodiments. [Figure 3] 10A-10C show examples of electrodes made using biomass-derived carbon-containing composite particles cast or deposited onto a current collector and filled with an electrolyte, according to various illustrative embodiments. [Figure 4] 10 shows another example of an electrode made using biomass-derived carbon-containing composite particles deposited on a current collector and filled with an electrolyte, according to various illustrative embodiments. [Figure 5] 1 shows an example of an embodiment in which active material (e.g., Li or Na metal or other metal in the case of a metal battery) is infiltrated into the (at least partially empty) pores of biomass-derived (or in some designs other types) porous carbon-containing particles of an electrode (e.g., anode) cast on a current collector during charging of the cell, according to various exemplary embodiments. [Figure 6]1 shows examples of suitable randomly shaped porous biomass-derived carbon powders that may be utilized in some exemplary embodiments of the present disclosure. [Figure 7] 1 illustrates an exemplary process that may be utilized to form a suitable composite including an active material and biomass-derived carbon, according to various exemplary embodiments. [Figure 8] 1 illustrates an exemplary method that may be utilized to form a suitable composite including an active material and biomass-derived carbon, according to various exemplary embodiments. [Figure 9] Yet another exemplary method is shown that may be utilized to form a suitable composite including active material and biomass-derived carbon, according to various exemplary embodiments. [Figure 10] Yet another exemplary method is shown that may be utilized to form a suitable composite including active material and biomass-derived carbon, according to various exemplary embodiments. DETAILED DESCRIPTION OF THE INVENTION

[0011] 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 described features, advantages, processes, or modes of operation, and alternative embodiments may be devised without departing from the scope of the invention. Furthermore, 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. Also, the phrase "at least partially" is intended to be interpreted as "partially, substantially, or completely."

[0012] Any numerical ranges recited herein with respect to any embodiment of the present invention are intended not only to define the upper and lower limits of the relevant numerical range, but also to implicitly disclose each separate value within that range in units or increments according to the level of precision by which the upper and lower limits are characterized. For example, a distance numerical range of 7 nm to 20 nm (i.e., a precision level in units or increments of 1) encompasses the set (in nm) of [7, 8, 9, 10, . . . , 19, 20], as if the intervening numbers 8 to 19 in units or increments of 1 were explicitly disclosed. As another example, a temperature range of about -120°C to about -60°C encompasses the set (in °C) of temperature ranges of about -120°C to about -119°C, about -119°C to about -118°C, and about -61°C to about -60°C, as if the intervening numbers (in °C) between -120°C and -60°C in the increment range were explicitly disclosed. In yet another example, a percent numerical range (i.e., a level of precision in hundredths or increments) of 30.92% to 47.44% encompasses (as a %) the set [30.92, 30.93, 30.94, . . . , 47.43, 47.44], as if the intervening numbers between 30.92 and 47.44 in hundredths or increments were expressly disclosed. Accordingly, any intervening numbers encompassed by any disclosed numerical range are intended to be construed as if those intervening numbers were explicitly disclosed, whereby such intervening numbers may constitute their own upper and / or lower limits of sub-ranges within broader ranges. Each sub-range (e.g., each range containing at least one intervening number from a broader range as an upper and / or lower limit) is thereby intended to be construed as implicitly disclosed by the explicit disclosure of that broader range.

[0013] While the following description may describe specific examples in the context of Li metal and Li ion batteries (for simplicity and ease of explanation, and due to the prevalence of current Li technology), various embodiments may also be used with other rechargeable and primary batteries (Na metal and Na ion, Mg metal and Mg ion, K metal and K ion, Ca metal and Ca ion, and other metal and metal ion batteries, OH -It should be understood that the present invention may be applied to other electrochemical capacitors (e.g., alkaline batteries with ions, mixed-ion batteries, etc.), other electrochemical capacitors (often referred to as supercapacitors or pseudocapacitors), or hybrid devices (e.g., one electrode is battery-like and the other electrode is electrochemical capacitor-like).

[0014] While the following description may describe specific examples in the context of active ions contained within active particles, it should be understood that various aspects may be applicable to active ions present in the electrolyte at some stage of cell assembly or charging or discharging.

[0015] Also, while the following description may describe specific examples of active material formulations in Li-containing states, it should be understood that various embodiments may be applicable to Li-free electrodes.

[0016] Additionally, while the following description may describe specific examples of active electrode materials belonging to so-called intercalation-type active materials, it should be understood that various embodiments may be applicable to so-called conversion-type active materials (including so-called alloyed-type active materials, true conversion-type active materials, chemically modified active materials, metal active materials, etc.), so-called pseudocapacitive active materials, so-called double-layer capacitor-type active materials, and mixed-type active materials (or active material components) that can store charge by more than one mechanism (e.g., active materials that exhibit both intercalation-type and conversion-type electrochemical reactions during cell operation, active materials that exhibit both intercalation and pseudocapacitance, or active materials that exhibit both intercalation and double-layer capacitor, among many other combinations).

[0017] Also, while the following description may describe specific examples of active materials (that reversibly store ions) in the form of crystalline (or nanocrystalline) materials (as components of (nano)composites), it should be understood that various aspects may be applicable to highly disordered or amorphous active materials.

[0018] Also, while the following description may describe specific examples of biomass-derived carbon materials, it should be understood that various embodiments may be applicable to other types of carbon materials, including those produced from both organic and inorganic precursors and those that utilize (e.g., sacrificial) templates for the formation of some of the pores.

[0019] Also, while the following description may describe specific examples of liquid organic electrolytes as components of electrochemical cells (batteries or electrochemical capacitors) based on (nano)composite electrodes, it should be understood that various embodiments may be applicable to aqueous electrolytes, ionic salt electrolytes, molten salt electrolytes, solid ceramic electrolytes, solid glass electrolytes, solid polymer electrolytes (including single-ion conducting solid polymer electrolytes in which some ions (e.g., cations) are mobile while the opposing ions (e.g., anions) are chemically bonded to the polymer backbone), gel electrolytes, composite (e.g., glass-ceramic, glass-polymer, ceramic-polymer, liquid-ceramic, liquid-polymer, liquid-ceramic-polymer, liquid-glass-polymer, or liquid-glass-ceramic-polymer) electrolytes, and others. In some designs, two or more electrolytes may be used in a single cell configuration (e.g., one electrolyte permeating / coating the surface of the electrode, active material and another electrolyte interpenetrating the remaining pores in the electrode or constituting at least a portion of the separator membrane; or, as another illustrative example, one electrolyte in contact with the anode and another electrolyte in contact with the cathode).

[0020] In some examples and designs, a solid electrolyte (at device operating temperatures) may melt and infiltrate at least some of the pores in the electrodes or active materials at elevated temperatures (at which the electrolyte becomes liquid). In some examples and designs, a solid electrolyte (at device operating temperatures) may be dissolved in a solvent and infiltrate the pores of the electrolyte (or active materials), followed by solvent evaporation (drying). The remaining pores may be filled with another electrolyte in a fully assembled device (such as a Li-ion battery cell).

[0021] In some examples and designs, the polymer electrolyte may infiltrate at least some of the pores in the electrode or active material in a liquid state and polymerize after infiltration (e.g., during heating or after sufficient storage in a suitable temperature range). In some designs, such polymerization may occur before use (application) of the cell. In some designs, such polymerization may occur after assembly of the cell. In some designs, such polymerization may occur after sealing of the cell.

[0022] During the operation of a battery (such as a Li-ion battery), intercalation-type active materials operate by the insertion (intercalation) and extraction (deintercalation) of Li-ions into and from interstitial locations (nanoscale or sub-nanoscale voids) present in the crystalline or disordered or completely amorphous structure of such intercalation compounds. This intercalation / deintercalation process is achieved by a change in the oxidation state of non-Li atoms (ions) (e.g., transition metal ions). Chemical bonds are typically not broken or reformed during such a process. Li-ions diffuse into and out of the active material.

[0023] During operation of a battery (e.g., a Li-ion battery), the conversion material changes (is converted) from one crystalline structure to another (hence the name "conversion"). During battery operation (e.g., Li-ion), Li ions are inserted into alloying-type materials to form lithium alloys (hence the name "alloying"). "Alloying"-type electrode materials (typically metals and metalloids) are sometimes considered a subclass of "conversion"-type electrode materials. "Alloying"-type electrode materials may also contain other types of conversion materials (oxides, hydrides, nitrides, etc.) as additives in small amounts (e.g., about 0.1% to 50% by weight) that can help increase the mechanical or electrochemical stability of the alloying materials or their electrical conductivity in the delithiated state (they may be intercalation-type materials), or other minor active materials (which may represent a very low, e.g., about 0.01% to 30% of the alloying material weight capacity). The electrochemical reaction process between the Li ions and the alloying or conversion material may be achieved by breaking some of the original chemical bonds and forming new chemical bonds. In the ideal case of some designs, the process is somewhat reversible, with only a small (e.g., preferably no more than about 30% over the life of the battery) or no loss of active material (i.e., Li) occurring during battery operation.

[0024] While the following description may describe specific examples in the context of metal-ion batteries, other conversion-type electrodes that may benefit from various aspects of the present disclosure include various chemistries used in a wide range of aqueous batteries, such as alkaline batteries, metal hybrid batteries, lead-acid batteries, etc. These include, but are not limited to, various metals (iron, zinc, cadmium, lead, indium, etc.), metal oxides, metal hydroxides, metal oxyhydroxides, and metal hydrides, to name a few.

[0025] While the following description may describe specific examples in the context of metal fluoride electrodes for metal-ion (e.g., Li-ion) or metal (e.g., Li) batteries, other conversion-type electrodes (including those containing fluorine) may benefit from various aspects of the present disclosure. Examples of such conversion-type active electrode materials may include, but are not limited to, various metal oxyfluorides, sulfofluorides, chlorofluorides, oxychlorofluorides, oxysulfofluorides, fluorophosphates, sulfophosphates, sulfofluorophosphates, mixtures of metals (e.g., Fe, Cu, Cu-Fe mixtures, other alloys, partially oxidized metals and metal alloys, etc.) and salts (e.g., metal fluorides (including LiF), metal chlorides (including LiCl), metal oxyfluorides, metal oxides, metal sulfofluorides, metal fluorophosphates, metal sulfides, metal oxysulfofluorides, various combinations thereof, etc.), among others, as well as other salts containing halogens, sulfur, oxygen, or phosphorus, or combinations of these elements.

[0026] FIG. 1 illustrates an exemplary metal or metal-ion (e.g., Li or Li-ion) battery to which the components, materials, methods, and other techniques disclosed herein, or combinations thereof, may be applied, according to various embodiments. While a cylindrical battery is shown here for illustrative purposes, other types of configurations, including prismatic or pouch (stacked-type) batteries, may also be used. The exemplary battery 100 includes an anode 102 (negative electrode), a cathode 103 (positive electrode), a separator 104 sandwiched between the anode 102 and the cathode 103, an electrolyte (not shown) that impregnates the separator 104 (and impregnates both the anode 102 and the cathode 103), a battery case 105, and a sealing member 106 that seals the battery case 105. In some designs for solid electrolytes, a solid electrolyte membrane may act as the separator 104.

[0027] Both liquid and solid electrolytes can be used with the designs herein. Conventional electrolytes for this type of Li- or Na-based battery generally consist of a single Li or Na salt (such as LiPF for Li-ion batteries and NaPF or NaClO salt for Na-ion batteries) in a mixture of organic solvents (such as a mixture of carbonates). Other common organic solvents that may be suitable in the context of one or more embodiments of the present disclosure include nitriles, esters, sulfones, sulfoxides, phosphorus-based solvents, silicon-based solvents, ethers, and others. Such solvents may be modified (e.g., sulfonated or fluorinated). Electrolytes can also include ionic liquids (neutral ionic liquids in some designs; acidic or basic ionic liquids in other designs). Electrolytes can also include mixtures of various salts (e.g., mixtures of multiple Li salts or mixtures of Li and non-Li salts for rechargeable Li and Li-ion batteries).

[0028] In the case of aqueous Li-ion (or aqueous Na-ion, K-ion, Ca-ion, etc.) batteries, suitable electrolytes may include solutions (e.g., aqueous or mixed aqueous-organic solutions) of inorganic Li (or Na, K, Ca, etc.) salts (LiSO, LiNO, LiCl, LiBr, LiPO, HLiOP, CFLiO, CFLiOS, NaOSe, NaSO, NaOSi, NaOP, CFNaO, etc.), to name a few. These electrolytes also include metal salts of carboxylic acids (HCOOLi, CH3COOLi, CH3CH2COOLi, CH3(CH2)2COOLi, CH3(CH2)3COOLi, CH3(CH2)4COOLi, CH3(CH2)5COOLi, CH3(CH2)6COOLi, CH3(CH2)7COOLi, CH3(CH2)8COOLi, CH3(CH2)9COOLi, CH3(CH2) 10 COOLi, CH3 (CH2) 11 COOLi, CH3 (CH2) 12 COOLi, CH3 (CH2) 13 COOLi, CH3 (CH2) 14 COOLi, CH3 (CH2) 15COOLi, CH3 (CH2) 16 COOLi, CH3 (CH2) 17 COOLi, CH3 (CH2) 18 COOLi and others having the formula CH3(CH2)xCOOLi where x ranges up to 50; metal salts of sulfonic acids (e.g., CH3SO3Li, CH3CH2SO3Li, C6H5SO3Li, CH3C6H4SO3Li, CF3SO3Li, [CH2CH(C6H4)SO3Li] n and others, where R is a metal salt of an organic radical, such as RS(=O)2-OH) and various other organometallic reagents (such as various organolithium reagents). Such solutions can also include mixtures of inorganic and organic salts, various other salt mixtures (e.g., mixtures of Li salts and salts of non-Li metals and metalloids), optional hydroxides (LiOH, NaOH, KOH, Ca(OH)2, etc.), and optional acids (including organic acids). In some designs, such aqueous electrolytes can include neutral, acidic, or basic ionic liquids (from about 0.00001 wt. % to about 40 wt. % based on the total weight of the electrolyte). In some designs, such "aqueous" (or water-containing) electrolytes can also include organic solvents (from about 0.00001 wt. % to about 40 wt. % based on the total weight of the electrolyte) in addition to water. Illustrative examples of suitable organic solvents can include carbonates (e.g., propylene carbonate, ethylene carbonate, diethyl carbonate, dimethyl carbonate, ethyl methyl carbonate, fluoroethylene carbonate, vinylene carbonate, and the like), various nitriles (e.g., acetonitrile, and the like), various esters, various sulfones (e.g., propane sulfone, and the like), various sultones, various sulfoxides, various phosphorus-based solvents, various silicon-based solvents, various ethers, and the like.

[0029] The most common salt used in certain conventional Li-ion battery electrolytes is, for example, LiPF, but less common salts that may also be suitable in the context of one or more embodiments of the present disclosure include lithium tetrafluoroborate (LiBF), lithium perchlorate (LiClO), lithium bis(oxalate)borate (LiB(C2O4)2, lithium difluoro(oxalate)borate (LiBF2(C2O4)), various lithium imides (SO2FN), and lithium tetrafluoroborate (LiPbF4). = (Li + )SO2F, CF3SO2N = (Li + )SO2CF3, CF3CF2SO2N = (Li + )SO2CF3, CF3CF2SO2N = (Li + )SO2CF2CF3, CF3SO2N = (Li + )SO2CF2OCF3, CF3OCF2SO2N = (Li + )SO2CF2OCF3, C6F5SO2N = (Li + )SO2CF3, C6F5SO2N = (Li + )SO2C6F5 or CF3SO2N = (Li + )SO2PhCF3 and others) and others. Electrolytes for Mg-ion, K-ion, Ca-ion, and Al-ion batteries may be more exotic as these batteries are in early stages of development. These exotic electrolytes may contain different salts and solvents (in some cases, ionic liquids may replace organic solvents for certain applications). In some designs, two or more Li salts may be advantageously used in the electrolyte. In some designs, electrolytes for Li-ion batteries may also advantageously contain non-Li salts.

[0030] Some electrolytes in aqueous batteries (e.g., alkaline batteries, including nickel-metal hydride batteries, among others) may include alkaline solutions (e.g., a mixture of KOH and LiOH solutions). Some electrolytes in aqueous batteries (e.g., lead-acid batteries) may include acidic aqueous solutions (e.g., aqueous H2SO4 or aqueous HCl). Some electrolytes in aqueous batteries may include an organic solvent as an additive. Some electrolytes in aqueous batteries may include two or more organic solvents, inorganic liquids, or surfactants as additives or substantial components of the electrolyte.

[0031] Conventional electrodes utilized in Li or Li-ion batteries can be produced by (i) forming a slurry containing active material, conductive additives, a binder solution, and, optionally, surfactants or other functional additives; (ii) casting the slurry onto a metal foil (e.g., Cu foil for most anodes used in Li or Li-ion batteries, Al foil for most cathodes used in Li or Li-ion batteries, as well as high-potential anodes used in Li-ion batteries, such as lithium titanate); (iii) drying the cast slurry to completely evaporate the solvent; and (iv) selectively densifying the electrode (e.g., by pressure calendering). Instead of using a solvent-based process for such electrode fabrication, some designs may benefit from dry electrode processing (which does not use solvents), including, but not limited to, electrostatic coating.

[0032] Conventional cathode materials utilized in Li and Li-ion batteries may be of the intercalation type. Metal ions intercalate and occupy intracellular sites of such materials during charging or discharging of the battery. Such cathodes undergo very little volume change when used in an electrode. Such cathodes typically have a high density (e.g., about 3.8-6 g / cm). 3), which is relatively easy to mix into a slurry. Polyvinylidene fluoride or polyvinylidene difluoride (PVDF) is one of the most common binders used in such electrodes. Carbon black is the most common conductive additive used in such electrodes. However, such cathodes have relatively low gravimetric and volumetric capacities (e.g., less than 220 mAh / g and 1000 mAh / cm, respectively). 3 (less than)

[0033] In many applications and electrode designs, batteries with intercalation-type cathode and anode materials can exhibit high charge / discharge rates (e.g., charging to about 80% of maximum capacity within about 10-60 minutes). However, in some applications (e.g., for even faster performance (e.g., charging to about 80% of maximum capacity within 1-600 seconds), or for better stability or performance at low or high temperatures), it may be advantageous to create composites containing such intercalation-type active materials and use them in electrodes for batteries or hybrid devices. In some designs, so-called pseudocapacitive materials may be utilized instead of or in addition to pure intercalation-type active materials. Electrodes may consist of 100% of such composites or may consist of a mixture of composites and "normal" active materials. Suitable mass fractions of composite particles in such "mixed" electrodes can range from about 1 to about 99 wt. % of the total active material particles in a given electrode (not considering the weight of binders, conductive and other additives, or other current collectors), depending on the requirements and demands of the application. In some designs, fractions less than about 1 wt. % are too low to make a substantial difference. Similarly, in some designs, fractions greater than about 99 wt. % are so high that they result in an undesirable increase in the complexity and cost of the electrode mix, and would be better replaced by about 100 wt. % of the composite without any substantial sacrifice in electrode properties. However, any fraction (from about 0 to about 100 wt. %) may be appropriate for some applications. In some designs, it may be even more advantageous for such composites to include carbon due to carbon's high electrical conductivity, acceptable mobility for Li and other ions, and good chemical and electrochemical resistance. In some designs, such carbons are predominantly (e.g., about 90-100%) sp (e.g., to achieve high electrical conductivity or for other performance benefits). 2 It can be advantageous to include -bonded carbon atoms. In some designs (e.g., for higher rate performance), the carbon is preferably oriented at a rate of (e.g., about 1 S / m to about 10 6It may be advantageous for the carbon to be sufficiently electrically conductive (having an electrical conductivity in the range of 0.5 S / m). In some designs, it may be advantageous (for performance, morphology, scalability, and cost reasons, among others) for the carbon to be derived from biomass (including natural renewable biomass).

[0034] Furthermore, biomass-derived carbon can typically be easily distinguished from carbon derived from synthetic resins, inorganic carbon sources, or other carbon sources by, for example, observing their morphologies on a submicron scale by scanning electron microscopy (SEM) and other techniques. Furthermore, carbon from different biomass sources can also be distinguished by the fact that the biomass sources exhibit structural features that are typically reflected in the final carbon product (e.g., after carbonization, purification, porosity enhancement, etc.).

[0035] In some designs, the rate performance characteristics (for rapid cycling) and cycling stability of such carbon-containing composite electrodes are such that the electrode area capacity loading is about 0.1-0.2 mAh / cm 2 When the electrode area capacity exceeds about 1-2 mAh / cm, it becomes particularly unsatisfactory for applications requiring ultrafast charging (e.g., within 1-600 seconds). 2 It becomes even more unsatisfactory when the electrode area capacity exceeds about 4 mAh / cm 2 However, higher loads are advantageous for reducing the cost of energy storage devices and increasing their energy density. One or more embodiments of the present disclosure may achieve a load of 0.1-0.2 mAh / cm. 2 For electrode area loads exceeding 1-2 mAh / cm 2 For loads in the range of about 4 to 4mAh / cm 2 The current focus is on the synthesis process, composition, and various physical and chemical properties of biomass-derived carbon-containing composite electrodes that enable satisfactory performance at loads exceeding 2 mAh / cm (e.g., in some designs, the areal capacity loading of the electrode composition is about 2 mAh / cm). 2 ~About 16mAh / cm 2 (It may be in the range of

[0036] In some designs, it may be advantageous for composites including such intercalation (or pseudocapacitive) active materials and biomass-derived carbon to have a significant weight fraction of active material, preferably from about 20% to about 98% by weight (in some designs, from about 40% to about 85% by weight). In some designs, the weight ratio of active intercalation (or pseudocapacitive) material to biomass-derived carbon may preferably range from about 1:4 to about 50:1 (in some designs, from about 1:3 to about 9:1). Too little fraction of intercalation (or pseudocapacitive) active material can result in low volumetric capacitance (or capacity, in the case of supercapacitors), while too much fraction of intercalation (or pseudocapacitive) active material can result in reduced rate and stability.

[0037] In some designs (e.g., for higher charging rates), it may be advantageous for the biomass-derived carbon-containing composite with such intercalation-type (or pseudocapacitive) material to contain pores. In some designs, the volume of the pores in the composite is about 0.01 cm. 3 / g ~ approx. 1.5cm 3 / g (in some designs, it may be advantageous for the pores to be in the range of about 2 vol.% to about 75 vol.%). In some designs, it may be advantageous for at least a portion of the pores (e.g., about 10 to 100 vol.%, e.g., about 20 to 100 vol.%; in some designs, about 50 vol.% to about 100 vol.%) to remain interconnected and accessible to the electrolyte while the electrode composition becomes part of the energy storage device cell. In some designs, it may be advantageous for at least a portion of the pores (e.g., about 1 to 100 vol.%) to be interconnected with adjacent pores and accessible from the center of the composite particle. In some designs, it may be advantageous for at least a portion of the pores (e.g., about 1 to 100 vol.%) to exhibit a characteristic dimension (e.g., diameter or width) in the range of about 0.3 nm to about 600 nm. In some designs, it may be advantageous for at least a fraction of the pores (e.g., about 0.1-30% by volume) to exhibit a characteristic dimension in the range of about 5 nm to about 50 nm (e.g., to maximize the volumetric capacity of the electrode while achieving high rate performance). In some designs, it may be advantageous for at least a fraction of the pores (e.g., about 30-100% by volume) to exhibit a characteristic dimension in the range of about 0.3 nm to about 10 nm (e.g., to maximize the volumetric capacity or improve the stability of the electrode). In some designs, it may be advantageous for at least a fraction of the pores (e.g., about 30-100% by volume) to exhibit a characteristic dimension in the range of about 0.3 nm to about 5 nm (e.g., to maximize the volumetric capacity or improve the stability of the electrode). In some designs (e.g., to maximize the volumetric capacity and volumetric energy storage properties of the electrode), it may be advantageous for the volume fraction of pores in such composites to be small (e.g., about 0.001-5% by volume) or moderate (e.g., about 5-20% by volume). In some designs (e.g., to maximize energy storage properties such as power or energy density or cycling stability, or to achieve a compromise between these or other properties), the so-called Brunauer-Emmett-Teller (BET) specific surface area (SSA) or density functional theory (DFT) SSA (e.g., measured using N, Ar, CO, or H sorption techniques and analyzed using BET or DFT methods) of the composite electrode material is less than about 0.5 m 2 / g~about 2000m 2 / g (approximately 10m in some designs) 2 / g~about 1000m 2 / g, in some designs, approximately 10m 2 / g~about 2000m 2 / g). A larger SSA may enable higher charge or discharge rate capability, but may also result in a higher fraction (rate) of some undesired side reactions (e.g., with the electrolyte). The rate of such undesired reactions (e.g., resulting in self-discharge, gasification, deposit formation, irreversible consumption of electrolyte, or electrode or cell swelling) may depend on the operating electrode potential and electrolyte composition. Acceptable rates depend on the specific application. However, for many electrolyte systems and for most cell designs and applications, it is generally believed that the BET SSA should be in the range of about 5 m 2 / g~about 1000m 2 In some designs, a BET SSA in the range of about 10 m 2 / g~about 200m 2 / g range may be preferred. In some designs (especially for higher BET SSA composites), it may be advantageous for the active (e.g., intercalation) material to be protected (from undesired interactions with the electrolyte) by a protective surface (shell) layer. In some designs, a suitable thickness for the protective surface layer may range from about 0.3 nm to about 60 nm. Smaller thicknesses may be insignificant for some applications, while larger thicknesses may result in reduced rate performance or reduced volumetric and gravimetric energy density for some applications. In some designs, the protective surface layer may directly coat at least a portion (e.g., about 1 to 100% of the exterior surface area) of the active material / particles that will be exposed to the electrolyte during at least some time of battery assembly or operation. In some examples, the protective surface layer may include carbon. In some examples, the protective surface layer may include oxides, fluorides, oxyfluorides, sulfides, nitrides, oxynitrides, fluoronitrides, phosphates, fluorophosphates (phosphofluorides), or other materials containing metal or semimetal atoms. In some designs, the protective surface layer material is selected from the group consisting of transition metals, alkali metals, and alkaline earth metals, such as iron (Fe), manganese (Mn), copper (Cu), yttrium (Y), zirconium (Zr), niobium (Nb), molybdenum (Mo), chromium (Cr), lithium (Li), sodium (Na), magnesium (Mg), potassium (K), calcium (Ca), strontium (Sr), cesium (Cs), and barium (Ba), lanthanum or lanthanides, such as La, Ce, Gd, Nd, and Eu, beryllium (Be), aluminum (Al), silicon (Si), gallium (Ga), germanium (Ge), phosphorus (P), arsenic (As), tin (Sn), bismuth (Bi), lead (Pb), and indium (In). It may include one or more of cadmium (Cd), zinc (Zn), fluorine (F), iodine (I), oxygen (O), nitrogen (N), sulfur (S), selenium (Se), tellurium (Te), hydrogen (H), and carbon (C).

[0038] In some designs (e.g., to maximize electrode uniformity and battery stability), it may be advantageous for such biomass-derived carbon-containing composite electrode particles to exhibit average characteristic dimensions (e.g., diameters) in the range of about 5 nanometers (nm) to about 150 microns. Too small a particle size may make it difficult to achieve high packing densities for some applications. At the same time, smaller particles may also result in small interparticle pore sizes, which may reduce rate performance in the electrode and, in some designs, lead to faster cell degradation (especially when the battery is operated at high rates or low temperatures). On the other hand, too large an average particle size may result in local variations in electrode capacity loading and, in some designs, lead to faster cell degradation (especially when the battery is operated at low rates or high temperatures). The composite particle size, the interconnectivity of pores in the composite, and the ion and electron transport properties within the composite may affect particle-level rate performance. In some designs, too large an average particle size may also result in low (or not sufficiently good for a given application) charge or discharge rate performance. Although various electrode and electrolyte characteristics, battery cell operating conditions (e.g., current, rate, temperature, charging voltage, electrode operating potential, etc.), composite particle porosity and shape, and other parameters influence the optimal composite particle size, in some designs it is advantageous for such composite electrode particles to exhibit average characteristic dimensions in the range of about 300 nm to about 20-30 microns (in some designs, about 0.5 microns to about 10 microns). The preferred electrode-level porosity (mostly the volume fraction of the void space in the electrode filled by electrolyte) can be affected by the volume fraction of the binder, the volume fraction of conductive and other additives, and the volume fraction of the active (composite) particles (and their open porosity), electrolyte conductivity, electrode thickness, battery operation, and other properties. However, values ​​in the range of about 1% by volume to about 75% by volume are acceptable for some applications. Smaller volume fractions may result in slow charge or discharge rates and rapid cell degradation in some applications. Larger fractions may reduce volumetric energy density and rate capability and increase battery cost in some applications. In some designs, the volume fraction of the electrode occupied (filled) with suitable electrolyte may advantageously range from about 1% to about 75% by volume.In some designs, a suitable volume fraction of the electrode occupied (filled) with a suitable electrolyte can be in a narrower range of about 5% to about 60% by volume (or an even narrower range, e.g., about 10% to about 40% by volume).

[0039] In some designs, the average size of the intercalation-type or pseudocapacitive-type particles (within the biomass-derived carbon-containing composite electrode particles) ranges from about 0.5 nm to about 200 nm (preferably from about 1 nm to about 60 nm in some designs; from about 2 nm to about 20 nm in some designs). Excessive size may not provide a fast enough electrochemical reaction in some designs, while excessive size may result in undesirable side reactions or excessive mass loading of the intercalation-type or pseudocapacitive-type particles in such composites, thereby limiting the energy performance of energy storage devices constructed with the composite particles in some designs.

[0040] In some designs, the intercalation-type or pseudocapacitive-type particles (of the composite electrode particles) may preferably be located within (e.g., trapped by) the pores of the biomass-derived carbon particles. In some designs, it may be preferable for at least a significant portion (e.g., about 20 to about 100%) of such pores to remain open. In some designs, about 50 to 100 wt. % of the active material in the composite particles may be trapped within the pores defined in the biomass-derived carbon particles.

[0041] In some designs, it may be advantageous to create two types of pores in carbon-containing composite electrodes (which are filled with electrolyte for cell assembly and battery operation): (i) “normal” pores between particles or within porous composite particles (as in “normal” battery or supercapacitor electrodes); and (ii) additional “channel” pores that are larger than the (average) “normal” pores and propagate from the surface of the electrode toward the current collector surface. In some applications, such “channel” pores can significantly enhance electrolyte permeation from the electrode surface, helping to enhance battery cell-level rate performance. In some designs, it may be advantageous for these “channel” pores to be straight (e.g., to minimize tortuosity in ion migration from the surface to the bulk and bottom of the electrode). It may even be advantageous for these “channel” pores to propagate more than about 25% of the electrode thickness (in some designs, more than about 50% of the electrode thickness, including a path through the entire electrode to the current collector; e.g., to more significantly enhance ion transport). In some designs, it may be advantageous for these "channel" pores to be regularly spaced (e.g., in a hexagonal, square, rhomboid, or rectangular pattern) (e.g., to achieve a minimum maximum distance from all particles in the electrode to the surface of the "channel" pores per given number of channel pores in a unit area of ​​the electrode). Note that in some designs, "normal" electrodes composed of "normal" intercalation active materials do not have such "channel" pores. This is in part due to the fact that "normal" electrodes in some designs do not require ultrafast charging (e.g., about 1 to 600 seconds). On the other hand, in some designs, carbon-containing composite electrode particles can be charged and discharged (inserting and extracting ions) substantially quickly, making it important that cell rate performance is not limited by ion transport kinetics at the electrode level. Thus, by way of example, the presence of such "channel" pores may be advantageous in the carbon-containing composite materials described above. This can be particularly important for moderate thicknesses of composite-containing electrodes (eg, about 25-75 microns per coated side), and even more so for larger thicknesses (eg, about 75-2000 microns per coated side).Furthermore, many intercalation-type (or pseudocapacitive) electrode materials exhibit small but significant volume changes (e.g., about 0.1 to 12% by volume) during charge and discharge, which can induce stresses within the electrode during battery operation in some designs. During the relatively slow operation of a "normal" electrode, such stresses are distributed relatively evenly within the electrode and do not result in mechanical failure. On the other hand, if a composite-containing electrode is charged or discharged significantly faster than a "normal" electrode, the level of stress may be higher and may even contribute to mechanical failure of the electrode. The presence of "channel" pores can reduce such stresses to levels acceptable for some applications. In composite particle designs according to embodiments of the present disclosure, the presence of carbon within the composite particle, as well as the presence of pores, can contribute to stress relief, and the presence of "channel" pores can also be advantageous for further stress relief and / or other performance gains. In some designs, it can be advantageous for the "channel" pores to have an average width, diameter, or thickness ranging from about 1 micron to about 500 microns (more preferably, from about 5 microns to about 200 microns). Channel pores less than 1 micron in an electrode may not be effective enough for some applications (especially for composite particles sized greater than about 1 micron) and may be expensive or difficult to produce. Pores larger than about 500 microns may reduce energy density and result in localized mismatches in capacity at the anode and cathode, which may contribute to failure in some applications, especially when the device is rapidly charged or discharged (e.g., faster than 1 hour, and even more so faster than 10 minutes). In some designs, it may be advantageous for the average spacing between "channel" pores in the electrode to be in the range of about 10 microns to about 10,000 microns (e.g., more preferably about 50 microns to about 1000 microns). Spacings less than 10 microns may be more difficult to produce in some designs and, most importantly, may result in reduced volumetric energy density of the device. Spacings greater than 10,000 microns may provide limited benefit, if any. The shape of the "channel" pores may vary between different applications. In some illustrative examples, the shape of the "channel" pores in the electrode may be cylindrical / cylinder-like, slit-like (or crack-like), V-shaped, caterpillar-like, among others.In some designs, the "channel" pores in the electrode may exhibit multiple branches (e.g., dendrites) to further enhance ion transport rates and minimize stress. The volume fraction of the "channel" pores may range from about 0.01% to about 30% by volume (as a volume fraction of the electrode). Larger "channel" pore fractions can significantly reduce the volumetric energy performance of the cell in some applications. Furthermore, in some cases, larger "channel" pore fractions can degrade the mechanical properties of the electrode and contribute to premature failure. The formation of "channel" pores can be induced by mechanical components (e.g., by using an indenter array), by using a sacrificial template, by forming "cracks" during electrode drying, by laser micromachining, and / or other mechanisms. In some designs, the "channel" pores in the electrode can be induced before or after electrode calendering (densification). In some designs, to achieve a favorable combination of favorable electrode mechanical properties, density, and pore size while using a more favorable (e.g., more reliable, less expensive, or faster) "channel" pore formation process, it may be advantageous to induce pores after partial calendering (densification) but before final calendering (densification). In some designs, it may be advantageous to heat the electrode (e.g., in addition to or separately from the heat applied thereto during calendering) during or after the introduction of "channel" pores into the electrode (but before filling the electrode with electrolyte). Heating may, in some designs, relieve some of the induced stresses or favorably change the mechanical properties of the electrode. The suitable temperature may vary and may depend on several factors (e.g., the type and thermal properties of the binder (if any) used, the thermal stability of the current collector, the thermal stability of the electrode, the thermal stability of conductive or other additives, the electrode thickness, etc.). In one example, the heating temperature may range from about 40° C. to about 200° C. (although in some special designs higher temperatures may be used - eg, up to about 600° C.).

[0042] In some designs (e.g., maximizing rate performance or battery stability), it may be advantageous for such biomass-derived carbon-containing composite electrodes to exhibit a compositional gradient from the electrode surface toward the current collector. In one illustrative example, it may be advantageous (e.g., to optimize rate performance) for the upper approximately 20-50% of the electrode to exhibit a significantly higher (e.g., about 10% to about 300% higher) porosity (to be filled with electrolyte) than the lower approximately 50-80% of the electrode. Here, the "lower" of the electrode refers to the portion of the electrode closest to the respective current collector, and the "upper" of the electrode refers to the portion of the electrode furthest from the respective current collector. In another illustrative example, it may be advantageous (e.g., to optimize rate performance and stability) for the upper approximately 20-50% of the electrode to comprise a significantly smaller average composite particle size (e.g., about 20% to about 30 times smaller) than the lower approximately 50-80% of the electrode. In yet another illustrative example, it may be advantageous (e.g., to optimize rate performance and stability) for about 20-50% of the upper portion of the electrode to contain significantly more porous composite particles than about 50-80% of the lower portion (e.g., composite particles having about 20% to about 50 times the volume fraction of pores within the composite particles). In yet another illustrative example, it may be advantageous (e.g., to optimize rate performance and stability) for about 20-50% of the lower portion of the electrode to contain significantly more conductive additive than about 50-80% of the upper portion (e.g., about 10% to about 5 times greater mass fraction of conductive additive). In yet another illustrative example, it may be advantageous (e.g., to optimize rate performance and stability) for about 10-50% of the lower portion of the electrode to contain significantly higher binder content than about 50-90% of the upper portion (e.g., about 10% to about 50 times greater mass fraction or volume fraction of binder per unit electrode mass or volume). In some designs (e.g., to maximize rate performance or battery stability), it may be advantageous for such biomass-derived carbon-containing composite electrodes to include a conductive intermediate layer between the current collector (e.g., a metal foil, a porous metal foil, a metal mesh, or other suitable type of current collector) and the electrode coating (e.g., one comprising composite particles, a conductive additive, and a binder). Such a conductive intermediate layer may reduce contact resistance (which may be particularly important for devices that undergo rapid charging or discharging) and further enhance the adhesion and mechanical stability of the electrode.Furthermore, such an interlayer may allow for a reduction in the binder fraction in the bulk of the electrode (e.g., for faster ion transport). In some designs, the thickness of such an interlayer may range from about 0.005 microns to about 5 microns (preferably, from about 0.05 microns to about 0.5 microns). Larger thicknesses may result in lower energy density and higher first cycle losses in some applications. However, too small a thickness (e.g., less than about 0.005 microns) may be less effective in improving current collector adhesion and reducing interfacial resistance in some applications. The interlayer may include a conductive additive (such as carbon nanotubes (either single-walled, double-walled, or multi-walled), carbon fibers, carbon nanofibers, carbon black, expanded graphite, graphene, or other types of conductive carbon, metal nanowires, carbon or metal-coated fibers or nanofibers, conductive polymers, etc.) or a mixture of several separate conductive additives and binders (e.g., a polymer binder or a carbonized / graphitized polymer binder). In some designs, the interlayer may be deposited by a spray coating process, by casting, by other mechanisms such as vapor deposition from a slurry suspension, or by electrostatic deposition or other mechanisms. In some designs, it may be advantageous for the interlayer to be grown or deposited on the surface of the current collector (e.g., by a vapor deposition technique such as chemical vapor deposition (CVD) or physical vapor deposition (PVD) including sputtering, by solution deposition, or by electrodeposition). In some designs, the porosity of the interlayer (e.g., filled with electrolyte prior to battery use) may range from a minimum of about 0% to a maximum of about 99%. In some designs, the interlayer may be designed to be intentionally separated from the current collector (e.g., upon heating above a predetermined temperature, such as about 80-150°C in one illustrative example) as a safety feature (e.g., to prevent thermal runaway in the battery cell). This may be achieved, for example, by using a polymer that shrinks and / or loses adhesion to the current collector above a predetermined temperature. Alternatively, as another illustrative example, the interlayer may become insulating above a predetermined temperature (e.g., due to a phase transition).

[0043] In some designs, the resulting biomass-derived carbon / intercalation-type active material composite particles may be further (at least partially) encapsulated in a functional shell layer (e.g., to enhance electrical conductivity, enhance ionic conductivity, enhance electrolyte wettability, prevent undesirable interactions between the electrolyte and the active material, or for other advantageous purposes). In some designs, the shell layer may preferentially coat either the active material or the carbon wall (e.g., by varying the wettability or nucleation time of the carbon surface relative to the wettability or nucleation time of the active material). In some designs, the volume fraction of the functional shell layer may range from about 0.001 vol% to about 20 vol% of the volume of the composite particle. In some designs, the functional shell layer may also act as the “active” material in terms of its ion storage capacity (e.g., it may exhibit a capacity in the range of about 0.1% to about 75% of that of the active material, when expressed in units of capacity per unit mass (mAh / g) or capacity per unit volume (mAh / cc)). In some designs, such a shelling material layer can be deposited using vapor deposition techniques (such as CVD, ALD, among others), electrochemical deposition, electrodeposition, electroless deposition, electrophoretic deposition, layer-by-layer deposition, or various other solution-based deposition techniques, or a combination of both solution deposition and vapor deposition. In some designs, the composite can be heat-treated (e.g., at a temperature of about 100 to about 1000°C) in a suitable gaseous environment (e.g., an inert gas such as N, Ar, or He, among others) or in vacuum after shelling material deposition to enhance composite properties. In some designs, the average thickness of the shelling material layer can vary depending on the particle size, ionic and electrical conductivity, and / or other properties of such layer. In some designs, a suitable thickness (e.g., average thickness) of the shelling material layer can range from about 0.2 nm to about 200 nm, although larger thicknesses may be acceptable in some applications (although perhaps at the expense of reduced volumetric capacity or reduced electrode porosity). In some designs, the shelling material layer is made of carbon (C) (e.g., in some designs, a predominantly conductive sp-type carbon, such as in graphite or graphitic carbon, turbostratic carbon, or most amorphous carbon).2 In some designs, various carbon atom containing solvents or various hydrocarbons (e.g., CH 12 , C5H 10 , C5H8, C6H6, etc.) may be advantageously used as precursors for carbon deposition. In some designs, hydrocarbon gases (e.g., CH4, C2H2, C2H4, C2H6, C3H6, C3H8, C3H4, C4H 10 , CH8, CH6, etc.) or combinations thereof may be advantageously used as precursors for carbon deposition. In some designs, viscoelastic polymers (including bio-derived ones such as pitch) may be used as precursors for carbon layer formation. In some designs, pitch may be derived from petroleum, coal tar, or plants (including wood). In some designs, the shelling material layer may be a composite of two or more materials. In some designs, the shelling material may include flake-shaped particles. In some designs, the shelling material is selected from the group consisting of the following elements: transition metals, alkali metals or alkaline earth metals (such as iron (Fe), manganese (Mn), copper (Cu), yttrium (Y), zirconium (Zr), niobium (Nb), molybdenum (Mo), chromium (Cr), lithium (Li), sodium (Na), magnesium (Mg), potassium (K), calcium (Ca), strontium (Sr), cesium (Cs), barium (Ba), among others), lanthanum or lanthanides (such as La, Ce, Gd, Nd, Eu), beryllium (Be), aluminum (Al), silicon (Si), gallium (Ga), germanium (Ge), phosphorus (P), arsenic (As), tin (Sn), bismuth (Bi), lead (Pb), indium (In). The shelling material layer may include one or more of cadmium (Cd), zinc (Zn), fluorine (F), iodine (I), oxygen (O), nitrogen (N), sulfur (S), selenium (Se), tellurium (Te), hydrogen (H), and carbon (C). In some designs, the shelling material layer may include a polymer. In some designs, the polymer used in the shelling material layer has high electrical and / or ionic conductivity (e.g., about 10 -7 ~about 10 +4In some designs, the polymer layer in the shelled material layer may be at least partially carbonized. In some designs, the shelled material layer may include a glass or ceramic layer. In some designs, the glass or ceramic layer may exhibit high electrical and / or ionic conductivity (e.g., in the range of about 10 -7 ~about 10 +4 In some designs, the shelling material layer may include a metal or metal alloy.

[0044] In some designs, biomass-derived carbon-containing composite particles can be produced by first producing porous biomass-derived carbon and then infiltrating the pores with an intercalation-type or pseudocapacitive-type active material. In some designs, such infiltration processes may be performed using vapor deposition techniques (such as CVD, atomic layer deposition (ALD), among others), solution infiltration techniques (including sol-gel or hydrothermal synthesis, layer-by-layer deposition, electrodeposition, electroless deposition, electrophoretic deposition, salt infiltration followed by solvent evaporation and decomposition, or conversion in a controlled environment, among others), melt infiltration (e.g., infiltration of a precursor or components of a precursor from a melt), or various combinations of two or more of such techniques (e.g., infiltration of a precursor (e.g., inorganic, metal-organic, or organometallic) salt from a solution or vapor phase, or melting followed by annealing or heat treatment in a controlled gaseous environment—e.g., a reducing environment (e.g., in a hydrogen-containing gas or vapor such as H or a hydrocarbon gas, among others), an oxidizing environment (e.g., in an O, F, Cl, or S-containing gas, among others), or a neutral environment (e.g., as N, Ar, or He gas or a vacuum), where the gaseous environment may contain molecules containing fluorine, hydrogen, oxygen, sulfur, phosphorus, lithium, sodium, potassium, calcium atoms, etc.). Thus, in some designs, the precursor may first be infiltrated and then converted to a suitable intercalation-type or pseudocapacitive active material, for example, by heat treatment in a suitable gas (or vapor) environment. In some designs, an additional layer of shelling material may at least partially encapsulate (or coat) the active material, carbon, or the entire composite particle, as previously described. The maximum heat treatment temperature (e.g., in a controlled environment) for such a process during composite formation may vary depending on the properties and composition of the intercalation-type active material composite (e.g., its thermal stability, mobility, reactivity in contact with carbon, etc.), but may range from about 100°C to about 1100°C (in some cases, from about 300°C to about 800°C).In some designs, two or more heat treatments may be performed in different gaseous environments (e.g., first under O or F-containing, then under Ar or N) at different temperatures (e.g., from about 50°C to about 1100°C) or pressures (e.g., from about 0.0001 Torr to 20,000 Torr; in some designs, near atmospheric pressure) and / or for different times (e.g., from about 0.0001 seconds to about 240 hours) to fine-tune the material synthesis (e.g., to form a composite with a desired active particle size and desired phase and stoichiometry of the active material particles, with the active particle size residing primarily within the carbon pores).

[0045] The biomass in the biomass-derived carbon-containing composite particles described above can be from a wide variety of sources. Furthermore, the properties of such biomass-derived carbon can vary widely. However, certain types of biomass, particular modes of converting biomass to carbon, and / or particular properties of biomass-derived carbon can be particularly attractive for certain battery designs (such as Li-ion batteries and others) and other types of electrochemical energy storage applications.

[0046] Renewable biomass-derived carbon from the following precursors has been found to be particularly attractive for certain biomass-derived carbon-containing composite particles based on intercalation-type active particles: (i) nut shells, especially coconut shells, apricot shells, and almond shells; (ii) fruit kernels, especially olive kernels, cherry kernels, apricot kernels, peach kernels, and avocado kernels; (iii) wood, including waste wood products; (iv) bamboo; (v) grass / straw and (dried) leaves, especially banana fiber, rice husks, corn cobs, and kelp; (vi) corn kernels; (vii) sycamore fluff; (viii) natural carbohydrates (including sugars), such as cellulose, chitin, alginate, sucrose, glucose, and starch, among others; or (ix) any combination thereof. The morphology of the biomass-derived carbon-containing composite particle can usually provide sufficient insight into the biomass source (precursor) of the corresponding carbon. The pore shapes and patterns and other structural features of biomass-derived carbon (e.g., from various plant sources) are often highly unique, as they follow the evolutionarily influenced heterogeneity of natural plant growth.

[0047] In some designs, the biomass-derived porous carbon particles have a so-called average BET specific surface area (SSA) (measured by CO, N, H, or Ar gas sorption) of about 400 m (prior to forming the composite). 2 / g~about 5000m 2 / g, and the pore volume is approximately 0.4 cm 3 / g ~ approx. 6cm 3 / g. In some designs, a suitable BET SSA is in the range of about 1000 m 2 / g~about 3000m 2 / g. 2 Above 400m / g, the composite becomes difficult to handle and produce, may result in poor performance in some designs, and may in some cases be too expensive to produce and handle (for battery applications). 2 / g or less may limit the rate performance and / or volumetric capacity (or capacitance) or other important properties of the composite in some electrochemical energy storage applications.

[0048] In some designs, the biomass-derived porous carbon particles have an open porosity in the range of about 35% to about 93% by volume, as determined by gas sorption (e.g., CO, N, H, or Ar) or other suitable measurement, and a surface area of ​​about 0.3 cm 3 / g ~ approx. 6cm 3 It may be advantageous to have a total open pore volume (e.g., void space) in the range of about 0.6 cm / g. In some designs, a suitable pore volume is about 0.6 cm. 3 / g ~ approx. 3.5cm 3 / g (approximately 0.75 cm in some designs) 3 / g ~ approx. 2.5cm 3 / g). The pore volume can be in the range of 6 cm 3 Above 0.3 m / g, the composite becomes difficult to handle and produce, may result in poor performance in some designs, and may in some cases be too expensive to produce and handle (for battery applications). 2 / g, the volumetric capacity of the composite (and hence the volumetric energy density of the cell) will be limited, limiting its usefulness in some applications.

[0049] In some designs, it may be advantageous for the biomass-derived porous carbon to exhibit a compositional purity of greater than about 90% by weight (e.g., less than 10% by weight of non-carbon species) prior to composite formation as determined by chemical composition, energy dispersive spectroscopy (EDS), thermogravimetric analysis (TGA), combustion analyzer, X-ray photoelectron spectroscopy (XPS), or other suitable mechanism. In some designs, a purity of greater than about 96% by weight is even more advantageous in some designs. In some designs, the so-called "ash" content should preferably be less than about 10% by weight (e.g., preferably less than about 4% by weight, more preferably less than about 2% by weight, even more preferably less than about 1% by weight, and most preferably less than about 0.25% by weight). In some designs, higher contents of various impurities (e.g., K, S, Ca, Na, Zn, P, O, etc.) can induce side reactions, significantly reduce cycling stability (especially at high temperatures), induce premature failure, reduce gravimetric and volumetric energy storage properties, reduce power density, result in undesirably large cell-to-cell or batch-to-batch variations, and possibly induce some other undesirable consequences that degrade the performance characteristics of electrochemical cells (e.g., Li-ion batteries). To achieve high-purity biomass-derived porous carbon, it can be advantageous to use a combination of chemical purification steps (e.g., treatment in acid) and thermal purification steps (e.g., heat treatment at temperatures of about 800°C to about 2000°C and evaporation of impurities).

[0050] In some designs, it may be important that the biomass-derived porous carbon contain less than about 10 wt. % (e.g., preferably less than about 2 wt. %, more preferably less than about 0.5 wt. %) of hydrogen atoms (present within its structure or as part of functional groups). In some designs, a higher hydrogen content (e.g., greater than about 10 wt. %) may result in undesirable gas formation and cell swelling, reduced capacity utilization, reduced cycling stability, higher first cycle loss, and / or other undesirable performance characteristics. Hydrogen content may be determined using a hydrogen analyzer, titration, nuclear reaction analysis (NRA), Devanathan-Stachurski method, combustion CHN analysis, gas composition analysis (IGA), scanning Kelvin probe force microscopy (SKPFM), and other suitable characterization mechanisms.

[0051] In some designs, it may be advantageous to use so-called physical activation techniques (e.g., activation in a stream of CO or HO, or both) to induce additional pores and increase the pore volume and surface area of ​​the bio-based carbon. In some designs, the preferred activation temperature may vary depending on the carbon type and pretreatment history. However, in some designs, the preferred temperature may range from about 700°C to about 1300°C (about 800°C to about 1150°C). In some applications, temperatures higher than about 1300°C may make it difficult to control the activation process to the desired uniformity and may induce undesirable pore size distribution within the carbon. In some applications, temperatures lower than about 700°C may make the activation process too slow, preventing the desired pore size and surface area characteristics from being achieved in the resulting activated bio-based carbon. In some designs, the formation of so-called hydrochar (carbon produced by hydrothermal treatment of hydrocarbon precursors, including various biomaterials such as shells and waste wood) may be advantageous prior to activation. In some designs, the biomaterial precursor may be annealed in an inert environment (e.g., in a vacuum or N2, Ar, or He gas) before activation. Suitable temperatures can range from about 500°C to about 2800°C, depending on the precursor and the desired porosity after activation. In some designs, heat treatment at temperatures below about 500°C has little effect on activation and may not remove the desired amount of impurities (e.g., as waste). In some designs, heat treatment at temperatures above about 2800°C is very effective in obtaining high-purity materials, but may hinder achieving a high BET SSA and maintaining small pores (which may be desirable) after activation. In some designs, chemical activation may be used instead of or in addition to (e.g., in combination with) physical activation. Examples of suitable chemical activators include, but are not limited to, KOH, NaOH, ZnCl2, H3PO4, K2CO3, or H2SO4. In some designs, the carbonization step proceeds simultaneously with chemical activation. In other designs, after carbonization of the bio-derived precursor, the resulting carbon may be mixed with a chemical activator and heat-treated for activation before being purified.In some designs, chemical activation may be preferred over physical activation due to the lower temperatures and shorter times required to activate the material, and in some cases due to the higher BET SSA achievable in high yield and the formation of larger amounts of smaller pores (e.g., pores in the range of about 0.4 to about 4 nm).

[0052] In some designs (e.g., to maximize rate performance or battery stability), it may be advantageous for such biomass-derived carbon (used in composite electrodes) to be heat-treated (annealed in a controlled environment) after the activation (and selective purification) process. In some designs, the annealing process may provide further purification, increase the electrical conductivity of the carbon, increase the mechanical properties of the carbon, reduce the number of nucleation sites (for active material deposition), and / or result in reduced self-discharge and other performance benefits for the cell (e.g., better rate, better stability, etc.). In some designs, suitable annealing temperatures may range from about 400°C to about 2400°C, depending on the precursors, gas composition and pressure, the porosity and microstructure of the activated carbon particles, the desired purity after activation, and the desired porosity. In some designs, higher annealing temperatures generally result in fewer nucleation sites and higher purity. However, in some designs, too high a temperature can reduce the BET SSA and pore volume, close some of the pores, make the material too hydrophobic (e.g., if the annealing is performed in an inert environment or vacuum), and / or induce other defects. In some designs, annealing may be advantageously performed both before and after carbon activation.

[0053] In some designs, it may be advantageous to mix (e.g., milled) bio-based carbon (including, but not limited to, expanded carbon, activated carbon, carbon black, etc.) with biopolymers (such as starch, various sugars, cellulose and cellulose-derived products, alginic acid and alginic acid-derived products, plant-derived pitch, gum arabic, various other natural polysaccharides, natural glycoproteins, and mixtures thereof, among others) and active material (nano)particles or precursors (e.g., salt; including saline solution) (either dry or in solution / suspension) and carbonize the resulting biomass-derived carbon-containing composite. In some designs, such a mixture may only include biopolymers and active material (or active material precursors) (without bio-based carbon particles). In some designs, it may be advantageous to utilize spray-drying or spray pyrolysis techniques for at least one step in the composite synthesis. In some designs, it may be advantageous to utilize hydrothermal (or solvothermal) treatment during at least one step in the composite synthesis (e.g., to induce oxidation or crystallization of the precursor at relatively low temperatures without burning / peroxidizing the carbon, etc.). In some designs, it may be advantageous to utilize hydrothermal treatment in combination with heat treatment in a controlled environment (e.g., a reactive environment such as oxygen-containing or fluorine-containing at low temperatures (e.g., from about room temperature to about 350-400°C), or inert at higher temperatures (e.g., from about 400°C to about 600-1200°C, depending on the particular chemistry and stability of the active material in contact with the carbon), or both). In some designs, polymers or carbons produced from non-renewable hydrocarbons (e.g., petroleum pitch, coal tar, etc.) rather than renewable biomass may be used equally effectively. In one example, the temperature of the pyrolysis or subsequent heat treatment (of the spray) may range from about 300°C to about 1200°C (in some designs, from about 450°C to about 1000°C), depending on the active material composition. In some designs, higher temperatures may result in undesirable reactions of the active material with the active material or carbon-forming carbides and other undesirable compositions. In some designs, lower temperatures may limit the rate capability and capacity of the resulting composite.

[0054] Illustrative examples of suitable Li-containing Li-ion intercalation active materials for use in biomass-derived carbon-containing nanocomposites include, but are not limited to, lithium titanium oxides (e.g., Li4Ti5O 12 ), lithium cobalt oxide (LiCoO2, LCO, or LiCo2O4), lithium nickel oxide (LiNiO2 or LNO), lithium manganese oxide (especially LiMnO2, LMO, Li2MnO3, or LiMn2O4), lithium nickel cobalt aluminum oxide (LiNi 0.8 Co 0.15 Al 0.05 O2, LiNi x Co y Al z O2, where typically x+y+z≦1, or NCA), lithium nickel manganese oxide (LiNi 0.5 Mn 0.5 O2, LiNi x Mn y O2, where typically x + y ≦ 1, or NMO), lithium nickel cobalt manganese oxide (LiNi 0.33 Co 0.33 Mn 0.33 O2, LiNi x Co y Mn z O2, where typically x+y+z≦1, NCM or NMC), lithium titanium sulfite (LiTiS2), lithium iron phosphate (LiFePO4, LFP), lithium manganese phosphate (LiMnPO4), lithium cobalt phosphate (LiCoPO4), lithium nickel phosphate (LiNiPO4), lithium vanadium fluorophosphate (LiVFPO4), lithium iron fluorosulfate (LiFeSO4F), various Li-rich materials (e.g., Li 1.211 Mo 0.467 Cr 0.3 O2, Li 1.3 Mn 0.4 Nb 0.3 O2, Li 1.2 Mn 0.4 Ti 0.4 O2, Li 1.2 Ni 0.333 Ti 0.333 Mo 0.133Lithium-rich (rock salt) transition metal oxides and oxyfluorides such as LiMnO, and many others), various high-capacity Li-ion based materials with partial substitution of oxygen with fluorine or iodine (e.g., rock salt, LiMn, among others). 2 / 3 Nb 1 / 3 O2F, Li2Mn 1 / 2 Ti 1 / 2 O2F, Li 1.5 Na 0.5 MnO 2.85 I 0.12 ) and many other types of Li-containing disordered layered tavorite, olivine, spinel-type active materials, or mixtures thereof containing at least oxygen, fluorine, or sulfur and at least one transition metal. In addition to Li-based active materials, other examples of intercalation-type active materials may be based on (e.g., similar) Na-ion intercalation compounds, K-ion intercalation compounds, Ca-ion intercalation compounds, among others. In addition to Li-containing (or Na-containing, K-containing, Ca-containing, etc.) intercalation compounds, Li-free (or Na-free, K-free, Ca-free, etc.) versions of such or similar materials may be utilized (e.g., titanium oxides or oxyfluorides, niobium oxides or oxyfluorides, cobalt oxides or oxyfluorides, nickel oxides or oxyfluorides, nickel-aluminum oxides or oxyfluorides, nickel-cobalt-manganese oxides or oxyfluorides, nickel-cobalt-aluminum oxides or oxyfluorides, iron oxides or oxyfluorides, iron phosphates, and many others, as well as various mixtures thereof).

[0055] In addition to or instead of intercalation-type active materials, some designs of biomass-derived carbon-containing nanocomposites may include so-called pseudocapacitive (or mixed pseudocapacitive-intercalation) active materials. Suitable examples of pseudocapacitive (or mixed pseudocapacitive-intercalation) active materials include, but are not limited to, various oxides, hydroxides, oxyhydroxides, nitrides, oxynitrides, nitrates, phosphates, (oxy)phosphates, sulfides, sulfate hydroxides, and other inorganic salts of Ru, Fe, Mn, Cu, Ti, Bi, V, Ni, Nb, Ce, Zr, Ta, Co, Sn, Sb, Si, In, Zn, Mo, Pb, La, and Y, as well as various mixtures and derivatives thereof. Such compounds may include Li, Na, Ca, Cs, Mg, and K. In some designs, such compounds may contain two, three, four, or more metals. In some designs, such compounds may also include at least one transition metal.

[0056] Conversion-type cathode and anode materials for rechargeable Li-ion or Li batteries can provide higher energy density, higher specific energy, or higher specific or volumetric capacity compared to intercalation-type cathode and anode materials.

[0057] For example, fluorine-based cathodes can sometimes exceed about 300 mAh / g (about 1200 mAh / cm at the electrode level). 3These materials offer significant technological potential due to their extremely high capacities (greater than 1000 mAh / g). For example, in the Li-free state, FeF3 provides a theoretical specific capacity of 712 mAh / g; FeF2 provides a theoretical specific capacity of 571 mAh / g; MnF3 provides a theoretical specific capacity of 719 mAh / g; CuF3 provides a theoretical specific capacity of 528 mAh / g; NiF2 provides a theoretical specific capacity of 554 mAh / g; PbF2 provides a theoretical specific capacity of 219 mAh / g; and BiF3 provides a theoretical specific capacity of 302 mAh / g. BiF5 gives a theoretical specific capacity of 441 mAh / g; SnF2 gives a theoretical specific capacity of 342 mAh / g; SnF4 gives a theoretical specific capacity of 551 mAh / g; SbF3 gives a theoretical specific capacity of 450 mAh / g; SbF5 gives a theoretical specific capacity of 618 mAh / g; CdF2 gives a theoretical specific capacity of 356 mAh / g; and ZnF2 gives a theoretical specific capacity of 519 mAh / g. Mixtures of fluorides (e.g., in the form of alloys) can provide approximate theoretical capacities according to the rules of mixture. The use of mixed metal fluorides can also be advantageous (e.g., can provide higher rates, lower resistance, higher practical capacity, or longer stability). In the fully lithiated state, the metal fluorides convert to composites containing a mixture of metal and LiF clusters (or nanoparticles). Examples of globally reversible reactions for conversion metal fluoride cathodes may include 2Li + CuF2 ↔ 2LiF + Cu for a CuF2-based cathode, or 3Li + FeF3 ↔ 3LiF + Fe for an FeF3-based cathode. It should be understood that metal fluoride-based cathodes may be prepared in either a Li-free, partially lithiated, or fully lithiated state.

[0058] In some designs, the use of so-called Li-air cathodes (e.g., cathodes having active materials in the form of LiO, LiO, LiOH in their lithiated states) or similar metal-air cathodes based on Na, K, Ca, Al, Fe, Mn, Zn, and other metals (other than Li) can be similarly beneficial due to their very high capacities. In some designs, such cathode active materials should ideally react reversibly with oxygen or oxygen-containing species in the electrochemical cell and can disappear completely upon complete delithiation (metal removal). These are also considered to belong to the conversion-type cathodes.

[0059] Other examples of promising classes of conversion-type cathode (or possibly anode) materials are sulfur (S) (in the Li-free state), lithium sulfide (LiS) (in the fully lithiated state), or other metal sulfides. To reduce active material dissolution during cycling, improve electrical conductivity, or enhance mechanical stability of S / LiS electrodes, certain designs may advantageously utilize porous S, LiS, porous SC (nano)composites, LiS-C (nano)composites, LiS-metal oxide (nano)composites, LiS-C metal oxide (nano)composites, LiS-C metal sulfide (nano)composites, LiS-C mixed metal oxide (nano)composites, LiS-C mixed metal sulfide (nano)composites, porous S polymer (nano)composites, or other composites or (nano)composites containing S or LiS, or both. In some designs, such (nano)composites may advantageously include conductive carbon. In some designs, such (nano)composites may advantageously include metal oxides or mixed metal oxides. In some designs, such (nano)composites may advantageously include metal sulfides or mixed metal sulfides. In some examples, the mixed metal oxides or mixed metal sulfides may include lithium metal. In some examples, the mixed metal oxides may include titanium, vanadium, manganese, or iron metals. In some examples, the lithium-containing metal oxides or metal sulfides may exhibit a layer structure. In some examples, the metal oxides, mixed metal oxides, metal sulfides, or mixed metal sulfides may advantageously (e.g., about 10 -7 ~about 10+4 In some cases, various other intercalation-type active materials may be utilized in place of or in addition to metal oxides or metal sulfides. In some designs, such intercalation-type active materials may be ionically and electrically conductive in potential ranges approaching those of S or LiS (e.g., Li / Li + (within approximately 1.5 to 3.8 V vs. ) exhibit charge storage (e.g., Li insertion / extraction capacity).

[0060] Conversion anodes are represented by nLi+M, where M is a metal or semimetal (intermetallic compound) and X is an anion (e.g., O in the case of the anode, but can also be N, S, P, F, etc.) or hydrogen (H). a X b ←→aM+bLi n They can provide higher specific capacities than graphitic carbon through reactions generalized by X. Suitable examples of such conversion-type active anode materials include, but are not limited to, various oxides, nitrides, sulfides, phosphides, fluorides, hydrides, and the like. Some designs may include, among others, fully or partially oxidized non-carbon Group IV elements (e.g., oxides, nitrides, sulfides, or phosphides of elements with atomic numbers 14, 32, 50, or 82), oxides, nitrides, sulfides, or phosphides of Al (atomic number 13), Ga (atomic number 31), In (atomic number 49), Sb (atomic number 51), Pb (atomic number 82), Bi (atomic number 83), Fe (atomic number 26), Ti (atomic number 22), Mn (atomic number 25), Cu (atomic number 29), Ni (atomic number 28), Co (atomic number 27), V (atomic number 23), and Zn (atomic number 30).

[0061] Unfortunately, many conversion-type active electrode materials (including those mentioned above) that can be used in Li or Li-ion batteries suffer from various performance limitations. The formation of biomass-derived carbon-containing (nano)composites can overcome, at least in part, such limitations. For example, biomass-derived carbon-containing (nano)composites can provide reduced voltage hysteresis, improved capacity utilization, improved stability, improved rate capability, improved mechanical stability, and in some cases improved electrochemical stability (e.g., a more stable cathode solid electrolyte interphase interface CEI or anode solid electrolyte interphase interface SEI), reduced volume fluctuation, and / or other favorable attributes.

[0062] Alloyed-type active anode materials for use in Li-ion batteries offer higher gravimetric and volumetric capacities than intercalation-type anodes. They can also offer lower irreversible first-cycle losses than conversion-type anode materials (such as various oxides, nitrides, sulfides, phosphides, or hydrides). However, such materials typically undergo significant volume expansion during Li insertion, which can lead to thickness changes or mechanical failure of the anode, their separation from the current collector, or damage to the current collector (e.g., Cu foil). Furthermore, some such anode materials suffer from relatively low electrical and ionic (Li-ion) conductivity. The volume change of such materials in response to electrochemical cycling can also lead to SEI damage, continuous electrolyte decomposition, and irreversible Li loss. In some designs, the formation of biomass-derived carbon-based (nano)composite particles containing such alloyed active particles (including, but not limited to, non-carbon Group IV elements (e.g., elements with atomic numbers 14, 32, 50, or 82), and Al (atomic number 13), B (atomic number 5), P (atomic number 15), Zn (atomic number 30), In (atomic number 49), Ga (atomic number 31), As (atomic number 33), Cd (atomic number 48), In (atomic number 49), Sb (atomic number 51), Pb (atomic number 82), Bi (atomic number 83), and various mixtures and alloys thereof) may, among other things, reduce volume change during Li-ion insertion and extraction, increase conductivity, increase capacity utilization, improve rate capability, improve mechanical stability, and in some cases improve electrochemical stability (e.g., a more stable solid electrolyte interphase interface (SEI)), reduce volume change, and impart other favorable attributes in rechargeable metal-ion (e.g., Li-ion) cells.

[0063] In some designs, the formation of biomass-derived carbon-containing (nano)composites with alloyed active materials may at least partially overcome such limitations. For example, they may provide reduced voltage hysteresis, improved capacity utilization, improved stability, improved rate capability, improved mechanical and possibly electrochemical stability (e.g., a more stable SEI), reduced voltage fluctuations, and / or other favorable attributes.

[0064] Metal anodes for use in metal batteries (e.g., Li metal anodes or Li alloy metal anodes for primary or rechargeable Li metal batteries) offer high gravimetric and volumetric capacities compared to intercalation-type anodes. Most commonly, such metal anodes are used directly in cell construction or in the form of metal foils deposited on a current collector during the first charge (after cell construction) with metal ions (e.g., Li ions) from a Li-containing cathode active material. Suitable examples of materials for the metal current collector of Li metal batteries include, but are not limited to, various metal foils that do not alloy with Li metal, such as Ni, Ti, steel, or Cu foils, and various Ni-, Ti-, Fe-, or Cu-based alloy foils, among others. The gravimetric and volumetric capacities of such Li metal foil anodes are very high, but they also offer moderate areal capacities (e.g., about 2-4 mAh / cm). 2 ) and high areal capacity (e.g., about 4-16 mAh / cm 2 Furthermore, such anodes suffer from various instabilities (e.g., pulverization, dendrite formation, volume change, separation from the current collector, undesirable reactions with the electrolyte resulting in irreversible capacity loss and anode swelling, resistive growth, etc.) and slow maximum charge / discharge rates.

[0065] In some designs, the formation of biomass-derived carbon-containing (nano)composites with Li metal (or other suitable metals for metal batteries) may at least partially overcome such limitations. For example, biomass-derived carbon-lithium metal composites may provide reduced voltage hysteresis, improved capacity utilization, improved stability, improved rate capability, improved mechanical stability and possibly improved electrochemical stability (e.g., a more stable SEI), reduced voltage fluctuations, and / or other suitable attributes. In some designs, such composites may advantageously include other materials in addition to biomass-derived carbon and lithium metal (e.g., other types of carbon, oxides, oxyfluorides, nitrides, polymers, etc.). In some designs, such composites may take the form of particles that are cast and formed into electrodes using a binder by a suitable mechanism (e.g., slurry coating, drying, calendering, and optionally coating with additional layers, or dry electrode coating, calendering, and optionally coating with additional layers). In some designs, such composites may form at least partially during the first charge (after cell construction) with metal ions (e.g., Li ions) from the Li-containing cathode active material. For example, Li metal may plate (electrodeposit) inside the pores of the biomass-derived carbon during the first charge. In some designs, it may be advantageous for at least a portion of such pores (e.g., about 10-100% of the pores) to be electrolyte-free and remain available for Li metal deposition during cell operation. In some designs, the pores within the biomass-derived porous carbon may be closed by forming a shell before or after electrode fabrication. In some designs, a solid electrolyte (e.g., a polymer, inorganic, or polymer-inorganic composite) may be advantageously utilized instead of a liquid electrolyte to reduce side reactions, reduce first-cycle capacity loss, reduce Li dendrite formation, and / or improve cell safety.

[0066] In some designs, the relatively poor performance characteristics and limited cycling stability of alloyed, metallic, and conversion-type electrodes are due to the fact that electrode capacity loadings are moderate (e.g., about 2-4 mAh / cm). 2 ) is particularly low, and when it is high (e.g., about 4 to 16 mAh / cm2 One or more embodiments of the present disclosure may achieve intermediate (e.g., about 2-4 mAh / cm) currents for alloyed, metallic, and conversion-type active materials. 2 ) and high capacity load (e.g., about 4 to 16 mAh / cm 2 This invention is directed to overcoming some of the above-mentioned problems through the formation of substantially more stable electrodes in a semiconductor device.

[0067] Although a wide range of alloyed, metallic, and conversion active materials (as well as the various intercalation and pseudocapacitive active materials mentioned above) have been successfully used in the construction of biomass-derived carbon-containing composites, some designs (e.g., when the active materials are loaded into composite particles or electrodes prior to assembly of the electrodes into a cell) require partial vapor pressures of approximately 10 at approximately 400 K. -10 torr (preferably less than 10 at about 400K) -13 It can be advantageous to employ active materials with a temperature range of 1000 torr or less. For example, in some designs, electrodes must be dried at approximately 400 K before cell assembly; substantial evaporation of the active material not only introduces contamination and poses a safety hazard, but also significantly reduces electrode uniformity and the resulting cell performance. In some designs, electrodes may be assembled from electrode compositions (including composite particles) during discharge conditions.

[0068] In many applications and electrode designs, batteries having conversion-type active electrode materials (cathode and anode materials) (including alloyed and metallic types) may exhibit acceptable charge / discharge rates (e.g., charging to about 80% of maximum capacity within about 60-1200 minutes) (at least for some applications), but unless the amount of conversion-type active material in the electrode is low (e.g., about 0.1-5 wt %) or moderate (e.g., about 5-20 wt %), they may suffer from poor cycling stability (e.g., less than about 200 cycles to about 80% of initial capacity), or high internal resistance or significant volume change that can result in damage to the current collector, separator, cell packing integrity, the electrode itself, irreversible cell-level swelling, or other undesirable consequences.

[0069] In some applications, it may be advantageous to form composites containing such conversion-type active materials (including alloyed and metallic types) and use such composites in battery electrodes to overcome one or more of the above limitations and achieve smaller expansion, better stability, and / or lower resistance. The electrode may be composed entirely of such composites with conversion-type materials (not considering binders, conductive and other additives, or other current collectors), or it may be composed of a mixture of the composite and an intercalation-type active material. In one example, a suitable mass fraction of composite particles in such a "mixed" electrode may range from about 1 to about 100 weight percent of all active material particles in a given electrode (not considering the weight of binders, conductive and other additives, or other current collectors), depending on the requirements and demands of the application. In some designs, it may be even more advantageous for such composites to include carbon due to carbon's high electrical conductivity, acceptable mobility of Li and other ions, and good chemical and electrochemical resistance. In some designs, such carbons are predominantly (e.g., about 90-100%) sp 2 It can be advantageous to include bonded carbon atoms. In some designs, the carbon is sufficiently bonded (e.g., from about 1 S / m to about 10 6 It may be advantageous for the carbon to have electrical conductivity (with electrical conductivities in the range of 0.5 S / m). In some designs, it may be advantageous (for performance, morphology, stability, and cost reasons, among others) for the carbon to be derived from biomass (including natural and renewable biomass).

[0070] In some designs, it may be advantageous for such biomass-derived carbon-containing composites to contain pores (e.g., to accommodate volume expansion upon lithiation when the active material is used in an unlithiated state). In some designs (e.g., for anodes and metal fluoride cathodes), once the composite is produced and used in a cell, it may be advantageous for all or at least a majority of the pores (e.g., about 50-100% by volume; in some designs, about 75% to about 100% by volume) to be sealed and remain inaccessible directly by the electrolyte or certain components of the electrolyte (e.g., by electrolyte solvent molecules in the case of a liquid electrolyte, or by the solid electrolyte in the case of a solid-electrolyte-containing cell). In some designs, this inaccessibility by the electrolyte may be achieved by sealing a portion of the pores before or after electrode assembly. In some designs (e.g., in the case of a solid electrolyte), this inaccessibility by the electrolyte may be achieved by the inability of the electrolyte to wet the interior pores during electrolyte infiltration. In some designs, it may be advantageous for at least a portion of the pores (e.g., about 1-100% by volume) to exhibit a characteristic dimension (e.g., diameter or width) in the range of about 0.3 nm to about 600 nm. In some designs, it may be advantageous for at least a fraction of the pores (e.g., at least about 0.1-30% by volume) to exhibit a characteristic dimension in the range of about 3 nm to 60 nm (e.g., to maximize the volumetric capacity of the electrode while achieving desired stability). In some designs, it may be advantageous for at least a fraction of the pores (e.g., about 30-100% by volume) to exhibit a characteristic dimension in the range of about 0.4 nm to about 15 nm (e.g., to achieve desired stability). In some designs, it may be advantageous for at least a fraction of the pores (e.g., about 30-100% by volume) to exhibit a characteristic dimension in the range of about 0.5 nm to about 10 nm (e.g., to improve stability and minimize volume change while achieving high capacity). In some designs (e.g., to maximize the volumetric capacity of the electrode), it may be advantageous for the pore volume fraction in such composites to be no more than about 5-100% of the volume required for the volumetric expansion of the active material upon full lithiation.

[0071] Apart from air cathodes, in some designs (e.g., to maximize energy storage properties such as power or energy density or cycling stability, or to achieve a compromise between these or other properties), the so-called Brunauer-Emmett-Teller (BET) specific surface area (SSA) or density functional theory (DFT) SSA (e.g., measured using N, Ar, CO, or H sorption techniques and analyzed using BET or DFT methods) of the composite electrode material is less than about 0.2 m 2 / g~about 100m 2 / g range. In some applications, a larger SSA can result in faster degradation and lower electrode density.

[0072] In some designs, the average size (e.g., diameter or thickness) of conversion-type active particles (including alloying-type particles, metal particles, or layers within biomass-derived carbon-containing composite electrode particles) ranges from about 0.5 nm to about 200-300 nm (preferably about 1 nm to about 60-100 nm in some designs; about 2 nm to about 20-30 nm in some designs). Too large a size can induce stress concentrations during volume change in some designs, potentially leading to mechanical failure of the composite during cycling. Furthermore, most conversion-type active materials undergo electrochemical reactions rather slowly, and smaller dimensions enhance rate performance. Too small a size can, in some designs, lead to undesirable side reactions or insufficient mass loading of intercalation-type or pseudocapacitive particles within such composites, limiting the energy performance of energy storage devices constructed with these composite particles.

[0073] In some designs, the conversion-type active particles (including alloyed particles, metal particles, or layers) of the composite electrode particles may be preferably located within the pores of the biomass-derived carbon particles. In some designs, it may be preferable for at least a significant portion (e.g., about 20 to about 100%) of such pores to remain sealed (e.g., with a shell material layer) to prevent direct electrolyte contact with the conversion-type active material.

[0074] In some designs, it may be advantageous for the (e.g., conversion, alloyed, or metallic) active material to be protected (from undesired interactions with the electrolyte) by a protective surface (shell) layer. In some designs, a suitable thickness for the protective surface layer may range from about 0.3 to about 60 nm. In some applications, smaller thicknesses may be insignificant, while larger thicknesses may result in reduced rate performance or reduced volumetric and gravimetric energy density. In some examples, the protective surface layer may include carbon. In some examples, the protective surface layer may include oxides, fluorides, oxyfluorides, sulfides, nitrides, oxynitrides, fluoronitrides, phosphates, fluorophosphates (phosphofluorides), or other materials containing metal or metalloid atoms. In some designs, it may be advantageous (e.g., for stability) for the protective surface layer to not undergo conversion reactions during battery cycling. In some designs, the protective surface layer material may be selected from the group consisting of transition metals, alkali metals, or alkaline earth metals (such as iron (Fe), manganese (Mn), copper (Cu), yttrium (Y), zirconium (Zr), niobium (Nb), molybdenum (Mo), chromium (Cr), lithium (Li), sodium (Na), magnesium (Mg), potassium (K), calcium (Ca), strontium (Sr), cesium (Cs), and barium (Ba), among others), lanthanum or lanthanides (such as La, Ce, Gd, Nd, and Eu), beryllium (Be), aluminum (Al), silicon (Si), gallium (Ga), germanium (Ge), phosphorus (P), arsenic (As), tin (Sn), bismuth (Bi), lead (Pb), and indium (In). It may include one or more of cadmium (Cd), zinc (Zn), fluorine (F), iodine (I), oxygen (O), nitrogen (N), sulfur (S), selenium (Se), tellurium (Te), hydrogen (H), and carbon (C).

[0075] In some designs (e.g., to maximize electrode uniformity, battery stability and performance, achieve acceptable rate performance, etc.), it may be advantageous for such biomass-derived carbon-containing composite electrode particles to exhibit average characteristic dimensions (e.g., diameters) in the range of about 5 nanometers (nm) to about 150 microns. In some applications, a too-small average particle size may generally make it difficult to achieve high packing densities. At the same time, in some designs, smaller particulates may also result in small interparticle pore sizes, which may reduce rate performance in the electrode and lead to faster cell degradation (particularly when the battery is operated at high rates or low temperatures). On the other hand, in some designs, a too-large average particle size may result in local variations in electrode capacity loading and lead to faster cell degradation (particularly when the battery is operated at low rates or high rates). The composite particle size, pore interconnectivity in the composite, and ion and electron transport properties within the composite may affect particle-level rate performance in some applications. Also, in some designs, an average particle size that is too large may result in low (or not sufficiently good for a given application) charge or discharge rate performance. While various electrode and electrolyte characteristics, battery cell operating conditions (current, rate, temperature, charge voltage, electrode operating potential, etc.), composite particle porosity and shape, and other parameters influence the optimal composite particle size, in some applications it may be advantageous for such composite electrode particles to exhibit average characteristic dimensions (e.g., average size) in the range of about 200 nm to about 20 microns (about 600 nm to about 10 microns in some designs, and about 600 nm to about 20 microns in some designs). In some designs, the preferred electrode-level porosity (e.g., the volume fraction of void space in the electrode that is at least partially filled by electrolyte) may be influenced by the volume fraction of binder, the volume fraction of conductive and other additives, and the volume fraction of active (composite) particles, electrolyte conductivity, electrode thickness, battery operation, volume expansion upon lithiation, and other properties. However, in some designs, values ​​ranging from about 7% to about 70% by volume are acceptable, and in some designs, smaller volume fractions may result in slow charge or discharge rates and faster cell degradation.In some designs, a larger volume fraction may result in reduced volumetric energy density, reduced rate capability, and increased battery cost. In some designs, the volume fraction of the electrode filled with a suitable electrolyte may advantageously range from about 7% to about 35% by volume. In some designs, the preferred volume fraction of the electrode filled with a suitable electrolyte may be in an even narrower range of about 15% to about 30% by volume.

[0076] In some designs, it may be advantageous for composites including such converted (or alloyed) active materials and biomass-derived carbon to have a significant weight fraction of active material, preferably from about 20% to about 95% by weight (in some designs, from about 30% to about 87% by weight). In some designs, the weight ratio of such active material to biomass-derived carbon may preferably range from about 1:4 to about 20:1 (in some designs, from about 1:3 to about 7:1). Too low a fraction of active material may result in low volumetric capacity in some designs, while too high a fraction of active material may result in reduced electrode stability and excessive volume change.

[0077] In some designs, it may be advantageous to create two types of pores in a composite electrode (which are at least partially filled with electrolyte for cell assembly and battery operation): (i) interparticle “normal” pores (as in “normal” battery or supercapacitor electrodes) and (ii) additional “channel” pores that are larger on average than the “normal” pores and propagate from the electrode’s surface toward the current collector surface. In one example, such “channel” pores can partially accommodate volume changes during cycling, improving electrode stability and reducing stress at the current collector-electrode interface, improving its mechanical stability. Furthermore, in some applications, such channels may allow for more uniform lithiation of the bulk of the electrode (especially at moderate and high rates, such as C / 3–4 C, defined as charge and discharge within 3–1 / 4 hours, respectively), which may further improve cycling stability. In some designs, it may be advantageous for these “channel” pores to be straight (e.g., to minimize the tortuosity of ion migration from the electrode’s surface to its bulk and bottom). In some designs, it may be even more advantageous for the "channel" pores to propagate more than about 25% of the electrode width (and in some designs, more than about 50%, including a path through the entire electrode to the current collector; e.g., significantly improving cell performance). In some designs, it may be advantageous for the "channel" pores to be regularly spaced (e.g., in a hexagonal, square, rhomboid, or rectangular pattern) (e.g., to achieve a minimum maximum distance from all particles in the electrode to the surface of the "channel" pores per given number of channel pores in a unit area of ​​the electrode). In some designs, regular spacing of the "channel" pores may be particularly important for moderate thicknesses of composite-containing electrodes (e.g., about 25-75 microns per coating side), and even more so for larger thicknesses (e.g., about 75-200 microns per coating side), which may exhibit the greatest stresses and fastest degradation. While the composite particle design, the presence of carbon, and the presence of pores within the composite particles can contribute to reducing the volume change and corresponding stress of the electrode, the presence of "channel" pores can also be highly advantageous in some designs.In some designs, it may be advantageous for the average width (for slit-shaped pores) or average diameter (for cylindrical or pyramidal shaped pores) of the "channel" pores to be in the range of about 3 microns to about 600 microns (e.g., more preferably about 10 microns to about 200 microns). In some designs, channel pores less than 3 microns in the electrode may not be effective enough and may be expensive or difficult to produce. In some designs, pores greater than 600 microns may reduce energy density, lead to local mismatches in capacity at the anode and cathode (thus reducing stability or cell energy), and may be difficult to produce for some applications. In some designs, it may be advantageous for the average spacing between "channel" pores in the electrode to be in the range of about 10 microns to about 10,000 microns (e.g., more preferably about 50 microns to about 1000 microns). In some designs, spacing less than 10 microns may be more difficult to produce and, importantly, may result in a reduction in the volumetric energy density of the device. In some designs, spacings greater than 10,000 microns have very limited effect. The shape of the "channel" pores can vary between applications or within a particular application (e.g., different "channel" pore shapes can be present in a particular particle). In some illustrative examples, the shape of the "channel" pores within the electrode can be, among others, cylindrical, slit-shaped (or crack-shaped), V-shaped, caterpillar-shaped, or any combination thereof. In some designs, the "channel" pores within the electrode can exhibit multiple branches (e.g., dendrite-shaped) to further enhance lithiation uniformity and minimize stress. In some designs, the volume fraction of the "channel" pores can range from about 0.01% to about 30% by volume (as a volume fraction of the electrode). In some designs, larger volume fractions of the "channel" pores can result in a significant degradation of the volumetric energy characteristics of the cell. Furthermore, in some cases, larger volume fractions of "channel" pores can reduce the mechanical properties of the electrode and contribute to premature failure.In some designs, the formation of "channel" pores can be induced by mechanical components (e.g., by using an array of indenters), by using a sacrificial template, by forming "cracks" during electrode drying, by using laser micromachining, and other mechanisms. In one example, "channel" pores in an electrode can be induced before or after electrode calendering (densification). In some designs, to achieve a favorable combination of suitable electrode mechanical properties, density, and pore size while using a more favorable (e.g., more reliable, cheaper, or faster) "channel" pore formation process, it can be advantageous to induce pores after partial calendering (densification) but before final calendering (densification). In some designs, it can be advantageous to heat the electrode during or after the introduction of "channel" pores in the electrode (but before filling the electrode with electrolyte). In some applications, heating can relieve some of the induced stresses or advantageously change the mechanical properties of the electrode. In one example, suitable temperatures can vary and depend on several factors (e.g., the type and thermal properties of the binder (if any) used, the thermal stability of the current collector, the thermal stability of the electrode, the thermal stability of conductive or other additives, the electrode thickness, etc.), although for some designs, the heating temperature may range from about 40°C to about 200°C (although higher temperatures may be used in some specialized designs—e.g., up to about 600°C).

[0078] In some designs (e.g., to maximize cell stability), it may be advantageous for such biomass-derived carbon-containing composite electrodes to exhibit a compositional gradient from the electrode surface toward the current collector. In one illustrative example, it may be advantageous (e.g., to optimize rate performance) for the upper approximately 20-50% of the electrode to exhibit a significantly higher (e.g., about 10% to about 300% higher) porosity (to be at least partially filled with electrolyte) than the lower approximately 50-80% of the electrode. In another illustrative example, it may be advantageous (e.g., to optimize rate performance and stability) for the upper approximately 20-50% of the electrode to contain a significantly smaller average composite particle size (e.g., about 20% less to about 30 times less) than the lower approximately 50-80% of the electrode. In yet another illustrative example, it may be advantageous (e.g., to optimize rate performance and stability) for the lower approximately 20-50% of the electrode to contain a significantly higher conductive additive (e.g., about 10% to about 5 times greater mass fraction of conductive additive) than the upper approximately 50-80% of the electrode. In yet another illustrative example, it may be advantageous (e.g., to optimize rate performance and stability) for the lower approximately 10-50% of the electrode to contain a significantly higher binder content (e.g., about 10% to about 5 times more mass or volume fraction of binder per unit electrode mass or volume) than the upper approximately 50-90%. In some designs (e.g., to maximize rate performance or battery stability), it may be advantageous for such biomass-derived carbon-containing composite electrodes to include a conductive interlayer between the current collector (e.g., metal foil, porous metal foil, metal mesh, or other suitable type of current collector) and the electrode coating (e.g., one comprising composite particles, conductive additives, and binder). In some designs, such a conductive interlayer can enhance the adhesion and mechanical stability of the electrode, which is particularly important for certain conversion-type electrodes due to the substantial volume change of conversion-type (including alloyed and metallic) active materials. Furthermore, in some designs, such an interlayer may enable a reduction in the binder fraction in the bulk of the electrode (e.g., for faster ion transport). In one example, the thickness of such an intermediate layer may range from about 0.005 microns to about 5 microns (eg, from about 0.05 microns to about 0.5 microns).In one example, a larger interlayer thickness may result in lower energy density and higher first cycle losses. However, in some applications, an interlayer thickness that is too small (e.g., less than about 0.005 microns) may not be very effective in improving current collector adhesion and reducing interfacial resistance. In one example, the interlayer may include a conductive additive (such as carbon nanotubes (either single-walled, double-walled, or multi-walled), carbon fibers, carbon nanofibers, carbon black, expanded graphite, graphene, or other types of conductive carbon, metal nanowires, carbon- or metal-coated fibers or nanofibers, conductive polymers, etc.) or a mixture of several separate conductive additives and a binder (e.g., a polymer binder or a carbonized / graphitized polymer binder). In some designs, the interlayer may be deposited by a spray coating process, by casting, by electrophoretic deposition, by dip coating, or by other techniques of vapor deposition from a slurry suspension. In some designs, it may be advantageous for the interlayer to be grown or deposited on the surface of the current collector (e.g., by a vapor deposition technique such as chemical vapor deposition (CVD) or physical vapor deposition (PVD), including sputtering, by solution deposition, or by electrodeposition). In some designs, the porosity of the interlayer (e.g., at least partially filled with electrolyte prior to battery use) may range from a minimum of about 0% to a maximum of about 99%. In some designs, the interlayer may be designed to be intentionally separated from the current collector (e.g., upon overheating above a predetermined temperature, such as about 80-150°C in one illustrative example) as a safety feature (e.g., to prevent thermal runaway in the battery cell). This may be achieved, for example, by using a polymer that shrinks and / or loses adhesion to the current collector above a predetermined temperature. Alternatively, as another illustrative example, the interlayer may become insulating above a predetermined temperature (e.g., due to a phase transition). Examples of suitable compositions may include various conductive polymer composites with pyroresistive behavior.

[0079] In some designs, the resulting biomass-derived carbon / converted active material composite particles may be further encapsulated (at least partially) in a functional shell layer (e.g., to prevent undesirable interactions between the electrolyte and the active material, or for other advantageous purposes). In some designs, the volume fraction of the functional shell layer may range from about 0.001% to about 20% by volume of the composite particle. In some designs, the functional shell layer may also act as the "active" material in terms of its ion storage capacity (e.g., when expressed in units of capacity per unit mass mAh / g or capacity per unit volume mAh / cc, it may exhibit a capacity in the range of about 0.1% to about 75% of that of the active material). In some designs, such a shell layer may be deposited using vapor deposition techniques (such as CVD, ALD, among others), electrochemical deposition, electrodeposition, electroless deposition, electrophoretic deposition, layer-by-layer deposition, or various other solution-based deposition techniques, or a combination of both solution deposition and vapor deposition. In some designs, the composite may be heat-treated in a suitable gaseous environment or vacuum (e.g., at temperatures of about 100 to about 1000°C) after shelling material deposition to enhance composite properties. In some designs, the average thickness of the shelling material layer may vary depending on the particle size, ionic and electrical conductivity of such layer, and other properties. In some designs, a suitable thickness may range from about 0.2 nm to about 200 nm, although larger thicknesses may be acceptable for some applications (possibly at the expense of reduced volumetric capacity of the electrode or reduced electrode porosity). In some designs, the shelling material layer is composed of carbon (C) (e.g., in some designs, a predominantly conductive sp-type carbon, such as in graphite or graphitic carbon, turbostratic carbon, or most amorphous carbons). 2 In some designs, various carbon atom containing solvents or various hydrocarbons (e.g., CH 12 , C5H 10 , C5H8, C6H6, etc.) may be advantageously used as precursors for carbon deposition. In some designs, hydrocarbon gases (e.g., CH4, C2H2, C2H4, C2H6, C3H6, C3H8, C3H4, C4H 10, CH8, CH6, etc.) or combinations thereof may be advantageously used as precursors for carbon deposition. In some designs, viscoelastic polymers (including bio-derived ones such as pitch) may be used as precursors for carbon layer formation. In some designs, pitch may be derived from petroleum, coal tar, or plants (including wood). In some designs, the shelling material layer may be a composite of two or more materials. In some designs, the shelling material may include flake-shaped particles. In some designs, the shelling material is selected from the group consisting of the following elements: transition metals, alkali metals or alkaline earth metals (such as iron (Fe), manganese (Mn), copper (Cu), yttrium (Y), zirconium (Zr), niobium (Nb), molybdenum (Mo), chromium (Cr), lithium (Li), sodium (Na), magnesium (Mg), potassium (K), calcium (Ca), strontium (Sr), cesium (Cs), barium (Ba), among others), lanthanum or lanthanides (such as La, Ce, Gd, Nd, Eu), beryllium (Be), aluminum (Al), silicon (Si), gallium (Ga), germanium (Ge), phosphorus (P), arsenic (As), tin (Sn), bismuth (Bi), lead (Pb), indium (In). The shelling material layer may include one or more of cadmium (Cd), zinc (Zn), fluorine (F), iodine (I), oxygen (O), nitrogen (N), sulfur (S), selenium (Se), tellurium (Te), hydrogen (H), and carbon (C). In some designs, the shelling material layer may include a polymer. In some designs, the polymer may have high electrical and / or ionic conductivity (e.g., greater than about 10 -7 ~about 10 +4 In some designs, the polymer layer may be at least partially carbonized. In some designs, the shelling material layer may include a glass or ceramic layer. In some designs, the glass or ceramic layer may exhibit high electrical and / or ionic conductivity (e.g., in the range of about 10 -7 ~about 10 +4 In some designs, the shelling material layer may comprise a metal or metal alloy. In some designs, it may be advantageous for the shelling material to not exhibit conversion reactions during repeated charge-discharge cycling of the electrode.

[0080] In some designs, biomass-derived carbon-containing composite particles can be produced by first producing porous biomass-derived carbon and then infiltrating the pores with a converted (or alloyed) active material. Such infiltration processes can be carried out using vapor deposition techniques (such as CVD, atomic layer deposition (ALD), among others), solution infiltration techniques (including sol-gel or hydrothermal synthesis, layer-by-layer deposition, electrodeposition, electroless deposition, electrophoretic deposition, or salt infiltration followed by solvent evaporation, among others), melt infiltration (e.g., infiltrating a precursor or components of a precursor from a melt), or various combinations of two or more of such techniques (e.g., infiltration of a precursor salt from a solution or vapor phase, or melting followed by annealing or heat treatment in a controlled gaseous environment—e.g., a reducing environment (e.g., in a hydrogen-containing gas or vapor such as H or a hydrocarbon gas, among others), an oxidizing environment (e.g., in an O, F, Cl, or S-containing gas, among others), or a neutral environment (e.g., N, Ar, or He gas or vacuum), where the gaseous environment can contain molecules containing fluorine, hydrogen, oxygen, sulfur, phosphorus, lithium atoms, etc.). Thus, in some designs, the precursor may first be infiltrated and then converted into a suitable conversion-type active material, for example, by heat treatment in a suitable gas (or vapor) environment. In some designs, as previously described, an additional layer of shelling material may at least partially encapsulate (or coat) the active material, carbon, or the entire composite particle. The maximum heat treatment temperature (e.g., in a controlled environment) for such a process during composite formation may vary depending on the properties and composition of the intercalation-type active material composite (e.g., its thermal stability, mobility, reactivity in contact with carbon, etc.), but may range, in one example, from about 80°C to about 1000°C (e.g., from about 200°C to about 700°C).In some designs, two or more heat treatments may be performed at different temperatures (e.g., from about 50°C to about 1000°C) or pressures (e.g., from about 0.0001 Torr to 20,000 Torr; in some designs, near atmospheric pressure) and / or for different times (e.g., from about 0.0001 seconds to about 240 hours) in different gaseous environments (e.g., first under an O- or F-containing, S-containing, P-containing, or N-containing gas composition, then under Ar or N) to fine-tune the optimal material synthesis (e.g., for the formation of a composite with a desired active particle size and desired phase and stoichiometry of the active material particles, with the active particle size residing primarily within the carbon pores).

[0081] The biomass in the biomass-derived carbon-containing composite particles described above can be from a wide variety of sources. Furthermore, the properties of such biomass-derived carbon can vary greatly between applications. However, certain types of biomass, as well as particular modes of converting biomass to carbon and particular properties of biomass-derived carbon, may be particularly attractive for certain types of batteries (such as Li-ion batteries and others) and / or other types of electrochemical energy storage applications.

[0082] In some designs, renewable biomass-derived carbon from the following precursors has been found to be particularly attractive for biomass-derived carbon-containing composite particles based on intercalation-type active particles: (i) nut shells, especially coconut shells, apricot shells, almond shells; (ii) wood, including waste wood products; (iii) natural carbohydrates (including sugars and sugar-containing natural compounds), such as cellulose, chitin, alginate, sucrose and glucose, gum arabic, and starch, among others.

[0083] In some designs, the biomass-derived porous carbon particles have a so-called BET specific surface area (SSA) (measured by CO, N, H, or Ar gas sorption) of about 500 m (prior to forming the composite). 2 / g ~ approx. 4400m 2 / g. In some designs, a suitable BET SSA is in the range of about 800 m 2 / g~about 3000m2 / g. BET SSA can be in the range of 4400m 2 Above 500 m / g, it may be difficult to produce a composite with sufficiently high mechanical stability to accommodate the volume change of the conversion material. 2 / g or less may limit the volumetric capacity (or capacitance) or other important properties of the composite in some electrochemical energy storage applications.

[0084] In some designs, the biomass-derived porous carbon particles have an open porosity (e.g., voids) ranging from about 30% to about 89% by volume as determined by gas sorption (e.g., CO, N, H, or Ar) or other suitable measurement, and a surface area of ​​about 0.2 cm 3 / g ~ approx. 3.7cm 3 It may be advantageous to have a total open pore volume in the range of about 0.6 cm / g. In some designs, a suitable pore volume is about 0.6 cm 3 / g~approx.3.0cm 3 / g (approximately 0.75 cm in some designs) 3 / g ~ approx. 2.5cm 3 / g). Some designs have a pore volume of 3.7 cm 3 Above 0.2 m / g, the composite is not strong enough to undergo volume changes without the formation of undesirable defects and cracks. In some designs, the pore volume is about 0.2 m 2 / g, the volumetric capacity of the composite (and hence the volumetric energy density of the cell) will be limited, thereby limiting its usefulness in these applications.

[0085] In some designs, it may be advantageous for the biomass-derived porous carbon to exhibit a compositional purity of greater than about 90% by weight (e.g., less than about 10% by weight of non-carbon species) prior to composite formation as determined by chemical composition, energy dispersive spectroscopy (EDS), and thermogravimetric analysis (TGA). In some designs, a purity of greater than about 96% by weight is even more advantageous. In some designs, the so-called "ash" content is less than about 10% by weight (e.g., preferably less than about 4% by weight, more preferably less than about 2% by weight, even more preferably less than about 1% by weight, and even more preferably less than about 0.25% by weight). In some applications, higher contents of various impurities (e.g., K, S, Ca, Na, Zn, P, O, etc.) can induce side reactions, significantly reduce cycling stability (especially at high temperatures), induce premature failure, reduce gravimetric and volumetric energy storage properties, reduce power density, result in undesirably large cell-to-cell or batch-to-batch variability, and / or possibly induce some other undesirable consequences that reduce the performance characteristics of electrochemical cells (e.g., Li or Li-ion batteries). To achieve high-purity biomass-derived porous carbon, it can be advantageous in some designs to use a combination of chemical and thermal purification steps.

[0086] In some designs, it may be important that the biomass-derived porous carbon contain less than about 10 wt. % (e.g., preferably less than about 2 wt. %, more preferably less than about 0.5 wt. %) of hydrogen atoms (present within its structure or as part of functional groups). In some designs, higher hydrogen content may result in undesirable gas formation and cell swelling, reduced capacity utilization, reduced cycling stability, higher first cycle loss, and / or other undesirable performance characteristics. In one example, hydrogen content may be determined using a hydrogen analyzer, titration, nuclear reaction analysis (NRA), Devanathan-Stachurski, scanning Kelvin probe force microscopy (SKPFM), or other suitable characterization mechanism.

[0087] In some designs, it may be advantageous to use so-called physical activation techniques (e.g., activation in a stream of CO or HO, or both) to induce additional pores and increase the pore volume and surface area of ​​the bio-based carbon. Suitable activation temperatures may vary depending on the type of carbon and its pretreatment history. However, by way of example, suitable temperatures may range from about 700°C to about 1300°C (in some designs, about 800°C to about 1150°C). In one example, temperatures higher than about 1300°C make the activation process very difficult to control to the desired uniformity and may induce undesirable pore size distribution within the carbon. In another example, temperatures lower than about 700°C may slow the activation process too much, preventing the desired pore size and surface area characteristics from being achieved in the resulting activated bio-based carbon. In some designs, the formation of so-called hydrochar (carbon produced by hydrothermal treatment of hydrocarbon precursors, including various biomaterials such as shells and waste wood) may be advantageous prior to activation. In some designs, the biomaterial precursor may be annealed in an inert environment (e.g., in a vacuum or N2, Ar, or He gas) before activation. In some designs, suitable temperatures can range from about 500°C to about 2800°C, depending on the precursor and the desired porosity after activation. In some designs, heat treatment at temperatures below about 500°C has very little effect on activation and may not remove (potentially desired) amounts of impurities (e.g., as waste liquid). In some designs, heat treatment at temperatures above about 2800°C is very effective in obtaining high-purity materials, but may inhibit achieving a high BET SSA and forming small pores (which may be desirable) after activation. In some designs, chemical activation may be used instead of or in addition to physical activation. Examples of suitable chemical activators include, but are not limited to, KOH, NaOH, ZnCl2, H3PO4, K2CO3, or H2SO4. In some designs, the carbonization step proceeds simultaneously with chemical activation. In other designs, after carbonization of the bio-derived precursor, the resulting carbon may be mixed with a chemical activator and heat-treated for activation before being purified.

[0088] In some designs (e.g., to maximize rate performance or battery stability), it may be advantageous for such biomass-derived carbon (used in composite electrodes) to be heat-treated (annealed in a controlled environment) after the activation (and optional purification) process. The annealing process may provide further purification, increase the carbon's electrical conductivity, improve its mechanical properties, reduce the number of nucleation sites (for active material deposition), and result in reduced self-discharge and other performance benefits for the cell (e.g., better rate, better stability, etc.). In some designs, suitable temperatures may range from about 400°C to about 2400°C, depending on the precursors, gas composition and pressure, the porosity and microstructure of the activated carbon particles, the desired purity after activation, and the desired porosity. In some designs, higher temperatures generally result in fewer nucleation sites and higher purity. However, too high a temperature can reduce the BET SSA and pore volume, close some of the pores, make the material too hydrophobic (e.g., if the annealing is performed in an inert environment or vacuum), and / or induce other defects. In some designs, annealing may be advantageously performed both before and after carbon activation.

[0089] In some designs, it may be advantageous to mix (e.g., milled) bio-based carbon (including, but not limited to, expanded carbon) with biopolymers (such as starch, sugars, cellulose and cellulose-derived products, alginic acid and alginic acid-derived products, plant-derived pitch, etc., among others) and active material (nano)particles or precursors (e.g., salts), and carbonize the resulting biomass-derived carbon-containing composite. In some designs, such a mixture may only include the biopolymer and active material (or active material precursor) (without the bio-based carbon particles). In some designs, it may be advantageous to utilize spray-drying or spray pyrolysis techniques for at least one step in the composite synthesis. In some designs, it may be advantageous to utilize hydrothermal (or solvothermal) treatment during at least one step in the composite synthesis (e.g., to induce oxidation or crystallization of the precursor at relatively low temperatures without burning / peroxidizing the carbon, etc.). In some designs, it may be advantageous to utilize hydrothermal treatment in combination with heat treatment in a controlled environment (e.g., a reactive one, such as an oxygen-containing, fluorine-containing, or sulfur-containing environment at low temperatures (e.g., below about 350-400°C), or an inert one at higher temperatures (e.g., from about 400°C to about 600-1200°C, depending on the specific chemistry and the carbon's resistance to reacting with or reducing the active material), or both). In some designs, it may be advantageous to utilize spray drying techniques or spray pyrolysis as at least one of the steps in the composite synthesis. In some designs, polymers or carbons produced from non-renewable hydrocarbons (e.g., petroleum pitch, coal tar, etc.) rather than renewable biomass may be used equally effectively. The temperature of the pyrolysis or subsequent heat treatment (spray) will vary depending on the active material composition, but may range, by way of example, from about 300°C to about 1200°C (in some designs, from about 450°C to about 1000°C). In some designs, higher temperatures may result in undesirable reactions of the active material with the active material or carbon-forming carbides and other undesirable compositions, and in some designs, lower temperatures may limit the rate capability and capacity of the resulting composite.

[0090] In some designs, it may be advantageous for electrodes containing conversion-type (including alloyed or metallic) active materials to further contain a polymer electrolyte. In some designs, such an electrolyte may reduce or prevent undesirable side reactions between the active material and the electrolyte (e.g., electrode dissolution), which may degrade cell performance in liquid electrolytes. The use of carbon in such composites may be advantageous in terms of reducing volume changes, which may make electrodes with liquid electrolytes more difficult to accommodate. In some designs, cells with conversion-type active materials containing composite electrodes may be based on a solid electrolyte (e.g., a polymer electrolyte or a ceramic electrolyte) that does not contain a liquid solvent.

[0091] In some designs, it may be advantageous for electrodes containing conversion-type (including alloyed or metallic) active materials or intercalation-type or pseudocapacitive active materials to be prepared in a particular manner or to contain particular binders or particular conductive or other additives.

[0092] For example, in some designs, deviations from a neutral pH may be advantageous when water is used as the slurry solvent (or slurry co-solvent) for at least one of the mixing stages of a carbon-containing electrode. In one example, pH adjustment may be advantageous to induce positive or negative charges on the surfaces of the active (nano)composite electrode particles or other particles in the slurry to achieve a more uniform dispersion. In another example, pH adjustment may be advantageously used to induce controlled adsorption of at least one of the binder components on the surfaces of the active (nano)composite electrode particles. Depending on the composition and surface chemistry of the particles in the slurry and the binder composition, optimal pH values ​​may range from about 3 to about 12 in some designs. In some applications, extreme pH values ​​(e.g., below 3 or above 12, depending on the slurry composition) may induce undesirable damage to the particles, the binder, or other co-solvents (if any).

[0093] In some designs, it may be advantageous to use one-dimensional (1D) conductive additives (single-walled carbon nanotubes, double-walled carbon nanotubes, multi-walled carbon nanotubes, carbon (nano)fibers, compatible metal nanofibers, nanotubes and nanowires (e.g., copper, nickel, titanium, iron nanowires / nanofibers, aluminum nanowires / nanofibers, nickel nanowires / nanofibers, etc.) in electrodes containing carbon-containing (nano)composite electrode materials. In some designs, when metal nanowires or nanofibers are used as conductive additives, it may be advantageous to coat some of them (e.g., Cu, Ni, Ti, or others) with a thin layer (e.g., about 0.2-10 nm) of conductive carbon or polymer (optionally bearing functional groups on its surface) or other functional surface layer to (i) prevent their corrosion during slurry preparation or handling, (ii) improve their dispersibility in the slurry, or (iii) improve their adhesion in the electrode.

[0094] In some designs, the surface of the (nano)composite particles may contain carbon. In the context of one or more embodiments of the present disclosure, the addition of chemical moieties to or functionalization of the carbon (or carbon-containing) surface of the subject electrode particles may provide many advantageous effects. In one example, a change in carbon surface chemistry may provide improved dispersibility during electrode slurry preparation. In yet another example, a change in surface chemistry may result in advantageous changes in interfacial interactions with the active particles, conductive additives, binders, electrolytes, and / or SEIs. In a further example, carbon functionalization may introduce triggers for the formation of strong covalent bonds between various carbon-containing materials (active electrode particles containing carbon or conductive additives on their surfaces) and (in some cases) between the carbon-containing materials and binders. In some cases, similar functional groups (or short molecular chains or small dendritic structures, e.g., less than about 80 atoms, chemically bonded to the electrode particle surface) may also be advantageous, even if the electrode particle surface does not contain carbon.

[0095] In some designs, the introduction of polar groups on the (carbon) surface can provide improved dispersibility in polar solvents such as water, N-methylpyrrolidinone, N,N-dimethylformamide, alcohols, etc., which allows for a more uniform slurry mixture and therefore a more uniform electrode. In some designs, the introduction of non-polar groups such as alkyl chains can provide improved dispersibility in non-polar solvents such as aliphatic hydrocarbons.

[0096] In some designs, it may be advantageous to attach the conductive additive to the (nano)composite electrode particles by other mechanisms. In one example, the conductive additive (e.g., carbon nanotubes, graphene, metal nanoparticles, or metal nanowires) may be directly on the surface of the electrode particles (e.g., by CVD or solution chemistry). In another example, conductive particles (of various shapes and sizes) may be firmly attached to the surface of the electrode particles by charging the surface of each (or most) particle and using the opposite charge of the electrode particles relative to the conductive additive particles. In yet another example, the conductive particles may be attached to the surface of the electrode particles using an organic (e.g., polymer) binder and carbonizing the binder to form a conductive carbon interlayer between the conductive additive and the electrode particles (e.g., effectively acting as a conductive adhesive). In yet another example, carbon may be preferentially deposited at the contact points between the electrode particles and the conductive additive by CVD deposition of a carbon layer on a mixture of the conductive additive particles and the active electrode particles. In one example, the CVD carbon layer may similarly act as a conductive adhesive to firmly attach the conductive additive to the electrode particles.

[0097] In some designs, the optimal weight percentage of the slurry components, given by the ratio of the mass of the inactive components to the external surface area of ​​the (nano)composite active electrode particles, is about 1 to about 5000 m per g of inactive components. 2 of activity (e.g., about 5 to about 200 mg per g of inactive ingredient) 2In some designs, the optimum weight percentages of the slurry components for a particular electrode composition may depend on the size of the active particles, the type of conductive additive, the surface chemistry of the conductive additive, the surface chemistry of the active particles, the density of the particles, the volume change during cycling, the type and molecular weight of the binder, the thickness of the electrode, the density of the electrode, and / or other parameters.

[0098] In some applications, it may be advantageous to induce opposite charges on the surfaces of the conductive additive and the (composite) electrode particles to increase their contact area and strength and achieve more uniform mixing. For example, a positive charge may be introduced on the surface of the composite particles, and a negative charge may be introduced on the surface of the conductive additive. In another example, a negative charge may be introduced on the surface of the composite particles, and a positive charge may be introduced on the surface of the conductive additive. In some applications, it may be advantageous to induce a chemical reaction between the conductive additive and the electrode particles during or after electrode drying.

[0099] In some designs, it may be advantageous to use two or more types of conductive additives (e.g., with different dimensions, aspect ratios, or morphologies) for optimal performance. In some designs, it may even be advantageous to chemically bond one type of conductive additive to the surface of the electrode particles. In this case, for example, the requirement for no expansion to maintain the stability of the electrode particle / conductive additive interface may be substantially reduced or even completely avoided. In one example, short (e.g., about 0.01 to 10 microns) carbon nanofibers, carbon nanotubes, or graphene / graphite ribbons may be grown from the surface of the electrode particles (e.g., by using catalytic chemical vapor deposition, CVD, or other mechanisms). In another example, a mixture of conductive carbon additive particles (e.g., carbon black, carbon nanotubes, etc.) with one charge and electrode particles with the opposite charge may be mixed with a small amount of a sacrificial binder and then carbonized. In some designs, the carbonized binder may firmly and permanently attach some of the carbon additive to the surface of the electrode particles. In one example, such electrode particle / carbon additive composites may be used in slurries with various suitable binders and additional conductive additives to form (or cast) more stable electrodes that undergo modest volume changes during cycling (e.g., as applicable in the context of the present disclosure).

[0100] In some applications, it may be advantageous to use two or more conductive additives with different surface charges or different surface chemistries. In particular, in some designs, one additive may be selected to form a uniform coating around the electrode particles if it exhibits a high affinity for the electrode particles. In some designs, such an additive may also be selected to form chemical bonds with the electrode particles during either the electrode assembly or slurry preparation stages. As an example, a second additive may be included in the binder at a significantly higher fraction than the first additive, thereby optimizing for the formation of a strong and uniform binder / additive (nano)composite that results in a stable electrode.

[0101] In some applications, two or more conductive additives may be selected to perform different functions. In one example, one type of additive (e.g., larger dimensions or higher conductivity, such as carbon nanofibers, other conductive nanofibers, long (e.g., greater than about 10 microns in length) carbon nanotubes, graphite or graphene flakes with linear dimensions greater than about 5-10 microns, other conductive flakes, metal nanowires, etc.) may be selected to provide higher electrical conductivity within the electrode as a whole, while a second type of conductive additive (e.g., carbon black and other conductive nanoparticles, shorter (e.g., average lengths of about 0.25-10 microns) carbon nanotubes, conductive nanowires or (e.g., chopped) conductive nanofibers, smaller graphene or graphite flakes, shorter graphite ribbons, etc.) may be selected to ensure that each individual electrode particle is effectively electrically connected to multiple adjacent electrode particles and the first type of additive, thereby forming an efficient conductive network that results in high capacity utilization of the electrode material. In other examples, one additive may be selected to perform multiple functions (e.g., to increase both the electrical conductivity and mechanical stability of the electrode, or to increase the electrical conductivity of the electrode and provide a fast ion path (e.g., if it is porous or it prevents blockage of the electrode pores)). In some designs, one conductive additive may also help to better disperse a second additive during slurry mixing.In particular, in some designs, it may be advantageous to use a mixture of two of the following types of conductive additives in the same slurry: (i) various types of single-walled carbon nanotubes (SWCNTs) (with or without surface coatings); (ii) various types of double-walled (DWCNTs), triple-walled (TWCNTs), and other types of multi-walled carbon nanotubes (MWCNTs) (with or without surface coatings); (iii) various types of carbon blacks (including those annealed above 1000°C in an inert environment); (iv) various types of carbon fibers (including those annealed above 1000°C in an inert environment); (v) various types of carbon nanofibers; (vi) various types of metal nanowires (with or without protective or functional surface coating layers) (e.g., low potential anodes in Li-ion batteries, such as Si-containing anodes), to name a few. (vii) various types of carbon- or metal- (e.g., Cu, Fe, Ni, Ti, or Al)-coated ceramic nanowires or fibers (e.g., Al2O3 nanowires or fibers); (viii) various types of carbon onions; (ix) various types of graphite ribbons (including metal-coated graphite ribbons); (x) various types of metal (e.g., Cu, Fe, Ni, Ti, or Al) nanoparticles (with or without protective or functional surface layer coatings); and (xi) various types of metal (e.g., Cu, Fe, Ni, Ti, or Al) (nano)flakes (with or without protective or functional surface layer coatings). In some designs, the surface chemistry of various such additives can be individually optimized for optimal performance in the cell.

[0102] In some applications, it may be advantageous to limit the overall volume fraction of all conductive additive particles in the electrode to about 5% by volume (even more preferably about 2% by volume or less). In some designs, by mass, the fraction of all conductive additive particles in the electrode may preferably be less than about 7% by weight (e.g., even more preferably less than about 3% by weight) when only carbon material is used as the conductive additive, and less than about 10% by weight (e.g., even more preferably about 5% by weight or less) when a portion of the conductive additive comprises a suitable metal. In one example, a high volume fraction of conductive additive may reduce the ion transport and volumetric capacity of the electrode and increase the extent of undesirable side reactions. In a further example, a high weight (mass) fraction of conductive additive may reduce the specific capacitance of the electrode.

[0103] 2A-2B illustrate two exemplary processes for the formation of biomass-derived carbon-containing composite particles. According to these exemplary embodiments, porous biomass-derived carbon particles 201 having small (e.g., about 0.3-20 nm) pores 202 and large (e.g., about 20-200 nm) pores 203 are infiltrated with a suitable active material 204 (e.g., in the form of nanoparticles 204) (e.g., by vapor deposition mechanisms or wet chemistry, which may also involve various thermal or hydrothermal treatments and combinations thereof) to reduce the volume fraction of the small pores 202 (and, in some designs, the large pores 203). According to the example of FIG. 2A , composite particles 201 are at least partially encapsulated in a shell 205 of appropriate thickness and composition (as described herein) that can prevent electrolyte access to small pores 202 (e.g., internal or encapsulated pores) and largely prevent direct contact between active material 204 and electrolyte when these composite particles are processed into battery electrodes (such as electrodes for Li metal, Li ion, Na metal, or Na ion batteries, or electrodes for other energy storage devices). According to the example of FIG. 2B , active material nanoparticles 201 are coated with a protective surface coating 206. A substantial portion (e.g., about 20-100% by volume) of the remaining pores 202 in FIG. 2B may remain open and, in some designs, accessible to electrolyte when these composite particles are processed into battery electrodes (or electrodes for other energy storage devices, such as supercapacitors or hybrid devices).

[0104] FIG. 3 shows an example of an electrode 300 produced using biomass-derived carbon-containing composite particles 301 cast or deposited on a current collector 302 and filled with an electrolyte 303. In this example, the biomass-derived carbon-containing composite particles 301 include small (e.g., less than about 20 nm) pores 305 that are at least partially filled (e.g., by about 30-100%) with active material 304 (e.g., in the form of nanoparticles), and the entire composite particle (or particles) 301 is coated with a shell 306 that at least partially seals the active material 304 and the remaining small pores 305. In some designs, the shell 306 can be pre-deposited on the particles 301 before electrode assembly by a suitable mechanism. In other designs, the shell 306 can be deposited on the particles 301 after electrode assembly by a suitable mechanism (e.g., from the gas phase using a suitable deposition technique such as ALD, CVD, or from a liquid phase). In some designs, a portion of the shell 306 can be deposited before electrode assembly, and another portion can be deposited after electrode assembly. In this illustrative example, the electrolyte 303 does not penetrate most of the small pores 305 and does not have direct contact with most of the active material volume. In some designs (e.g., when the active material belongs to so-called conversion-, alloyed-, or metal-type active materials for Li metal, Li ion, Na metal, Na ion, and other types of batteries), it may be preferable for the electrolyte 303 to have direct contact with about 0-10% by volume of the active material nanoparticles. In some designs, the electrolyte 303 may include a liquid organic electrolyte, a polymeric (solid polymer or gel-type) electrolyte, a solid inorganic electrolyte, a liquid inorganic electrolyte, or a hybrid (or composite / mixed) electrolyte.

[0105] FIG. 4 shows another example of an electrode 400 made using biomass-derived carbon-containing composite particles 401 deposited on a current collector 402 and filled with an electrolyte 403. In this example, the biomass-derived carbon-containing composite particles 401 include small (e.g., less than about 20 nm) pores 405 that are at least partially filled (e.g., by about 30-100%) with an active material 404 (e.g., in the form of nanoparticles). In this illustrative example, the electrolyte 403 may penetrate most (e.g., about 50-100%) of the remaining pores 405 to ensure direct contact with the majority of the active material volume. In some designs (e.g., when the active material belongs to so-called intercalation-type, pseudocapacitive, or mixed-type active materials), it may be preferable for the electrolyte 403 to have direct contact with about 50-100% of the active material nanoparticles by volume. In some designs, the electrolyte 403 can be an aqueous electrolyte, a liquid organic electrolyte, a polymer (solid polymer or gel type) electrolyte, a liquid inorganic or a hybrid (or composite / mixed type) electrolyte.

[0106] FIG. 5 shows an example embodiment in which active material 504 (e.g., Li or Na metal or other metal in the case of a metal-on-metal battery) is infiltrated into (at least partially empty) pores 502 of biomass-derived (or possibly other types of) porous carbon-containing particles 503 of an electrode (e.g., an anode) cast on a current collector 501 during cell charging. In this illustrative example, such an electrode may, in some designs, be assembled without active material. During discharge, a substantial portion (e.g., about 50-100%, preferably about 70-100%) of the active material (e.g., Li or Na metal) leaves the pores of the porous particles. At least a portion (e.g., about 50-100% by volume) of the pores of the biomass-derived carbon-containing particles 503 preferably remains inaccessible to the electrolyte 505 during cell assembly, thus providing space for metal (e.g., Li or Na) deposition. In some designs, it may be preferable for the electrolyte 505 to be solid (e.g., a solid polymer electrolyte, a polymer-ceramic composite electrolyte, or an inorganic solid electrolyte) and sufficiently rigid so that it is energetically favorable for metal to be deposited inside the pores to minimize strain energy (e.g., to prevent metal deposition on the outer surface of the particle and inducing side reactions or damage to the electrolyte). In some designs, the porous carbon-containing particles 503 may be produced from other carbon sources (e.g., including inorganic or hydrocarbon gases or synthetic or natural polymers, among others) rather than necessarily biomass, and may contain one or more closed pores. In some designs, these pores may range from about 0.3 nm to about 800 nm (larger than for many other embodiments).

[0107] Figure 6 shows an example of a suitable randomly shaped porous biomass-derived carbon powder that may be utilized in some exemplary embodiments of the present disclosure. In this example, SEM images are taken of activated carbon derived from waste wood products. The particle size distribution is somewhat broad—e.g., some particles are less than about 0.5 microns and some particles are larger than about 20 microns (e.g., up to about 70 microns in linear dimensions). However, the average particle size in Figure 6 is about 10 microns.

[0108] FIG. 7 illustrates an exemplary process that may be utilized to form a suitable composite including active material and biomass-derived carbon, according to various exemplary embodiments. According to this example, a suitable biomass is first provided as a carbon source (block 701). The biomass is then carbonized (e.g., by thermal or hydrothermal treatment, or both, or by other mechanisms) to produce biomass-derived carbon (block 702). The produced carbon is then refined (block 703) to achieve a sufficiently low level of impurities (low ash content). The produced carbon is then milled (block 704) to achieve an appropriate particle size (e.g., with an average size ranging from about 0.3 microns to about 30 microns). The milled carbon is then refined to achieve an appropriate specific surface area (e.g., about 400-600 m). 2 / g to approximately 2000-5000m 2 / g) and pore volume (e.g., about 0.2 to 0.4 cm 3 / g to about 4-6cm 3 The resulting carbon may be activated (e.g., by physical or chemical activation) to achieve a porosity of 0.1 / g (block 705). The resulting carbon of appropriate porosity is then infiltrated with active material particles by an appropriate mechanism (e.g., from a gaseous environment, by chemical vapor deposition, chemical vapor infiltration, atomic layer deposition, and / or other mechanisms, or by using solution or melt infiltration; subprocesses involved in appropriate active material formation / infiltration may include, among others, heating in an inert or reactive gas or liquid environment, hydrothermal treatment, solvothermal treatment, and combinations thereof) (block 706). The active material (e.g., in the form of nanoparticles) may then be (optionally) coated with a protective surface layer of appropriate thickness (e.g., about 0.25-50 nm) (block 707). A final step may (optionally) include forming a shell around the composite particles (e.g., to seal the pores and active material) (block 708). FIG. 8 illustrates an exemplary method that can be utilized to form a suitable composite including an active material and biomass-derived carbon, according to various exemplary embodiments. According to this example, a suitable biomass-derived carbon of appropriate size, porosity, and purity is first provided (block 801). The resulting carbon of appropriate porosity is then infiltrated with an active material precursor by an appropriate mechanism (e.g., using solution infiltration, vapor infiltration, chemical vapor deposition, melt infiltration, etc.) (block 802). The resulting composite is then processed in a first suitable (reactive or inert) gas or liquid environment (block 803), followed (optionally in some designs) by a second suitable (reactive or inert) gas or liquid environment (block 804) to achieve an active material of appropriate composition. The first processing (block 803) may induce decomposition of the precursor material or oxidation / conversion of the precursor material. The second processing (block 804) may induce further transformation or crystallization of the particles to achieve the desired active material composition. The resulting composite may then be (optionally) heat-treated (block 805) (e.g., to increase the size of the active material particles, induce crystallization of the active material, or remove undesired by-products or contaminants), and the active material (e.g., in the form of nanoparticles) may then be (optionally) coated with a protective surface layer of appropriate thickness (e.g., about 0.25-50 nm) (block 806), or the composite particles may be (optionally) encapsulated in a shell of appropriate properties (e.g., to seal the pores and active material) (block 807).

[0109] FIG. 9 illustrates yet another exemplary method that can be utilized to form a suitable composite including an active material and biomass-derived carbon, according to various exemplary embodiments. According to this example, a suitable biomass-derived carbon of appropriate size, porosity, and purity is first provided (block 901). The resulting carbon with the appropriate porosity is then infiltrated with an active material precursor by a suitable mechanism (e.g., by using solution infiltration, vapor infiltration, chemical vapor deposition, melt infiltration, etc.) (block 902). The resulting composite may then be (optionally) heat-treated (e.g., to increase the size of the active material particles, induce crystallization of the active material, or remove undesirable synthesis by-products or contaminants) (block 903). The active material or carbon may then (optionally) be coated with a protective surface layer of appropriate thickness (e.g., about 0.25-50 nm) (block 904), or the composite particles may (optionally) be encapsulated in a shell of appropriate properties (e.g., to seal the pores and active material) (block 905).

[0110] 10 illustrates yet another exemplary method that may be utilized to form a suitable composite comprising an active material and biomass-derived carbon, according to various exemplary embodiments. According to this example, a suitable biomass (or biomass-derived carbon-containing natural polymer or other biomass-derived carbon-containing natural material) is first provided (block 1001) and then finely mixed with a suitable active material precursor (block 1002). The mixing step may involve dry mixing (or milling), solution mixing (or milling), or both, at room temperature or elevated temperatures (e.g., from about room temperature to about 400° C.), with the goal of achieving a homogeneous composite comprising fine particles (200 nm or less) of precursor material in a matrix of biomass (or biomass-derived carbon-containing product). The mixture is then heat-treated in a first controlled environment (e.g., in a reactive or inert gas or liquid environment, such as a hydrothermal or solvothermal treatment) (block 1003), a second controlled environment (e.g., in a reactive or inert gas or liquid environment, such as a hydrothermal or solvothermal treatment) (block 1004), or a third controlled environment (e.g., in a reactive or inert gas or liquid environment, such as a hydrothermal or solvothermal treatment) (block 1005) to achieve the desired morphology and composition of the active material and biomass-derived carbon. The resulting composite may be milled to a desired particle size distribution (block 1006). Note that in some designs, the milling step may occur earlier (e.g., after the first or second processing step—after blocks 1004 or 1005). The active material or carbon may then be (optionally) coated with a protective surface layer of appropriate thickness (block 1006), and the composite particles may (optionally) be encapsulated in a shell of appropriate properties (e.g., to seal the pores and active material) (block 1007).

[0111] Nanocomposite particles can generally be of any shape (e.g., generally spherical, cylindrical, plate-like, randomly shaped, etc.) and any size. The maximum size of the particles can depend on rate performance requirements, the rate of ion diffusion into partially filled particles, and other parameters.

[0112] In one example, the "size" of a nanocomposite particle can be determined in any of a variety of ways. In one example, if the particle is spherical or near-spherical, the size of an individual particle can refer to the diameter of the particle. In another example, if the particle is non-spherical (e.g., ellipsoid, spheroid, etc.), the size of an individual particle can refer to the diameter of a sphere of equivalent volume of the particle (e.g., a sphere of the same volume and size representative of the particle). When the equivalent-volume sphere approach is used, the total pore volume from the particle is retained in the equivalent-volume sphere of the particle. In yet another example, for irregularly shaped particles (e.g., ellipsoidal particles), the size of an individual particle can refer to the smallest dimension (e.g., width) or length (e.g., total length) of the particle. Thus, the various particle size ranges described with respect to embodiments of the present disclosure can refer to sizes determined according to any of the above methods based on the shape and / or other characteristics of each particle.

[0113] This description is provided to enable any person skilled in the art to make or use embodiments of the invention. It is understood, however, that the invention is not limited to the particular methods, process steps, and materials disclosed herein, since various modifications to these embodiments will be readily apparent to those skilled in the art. Thus, the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention.

Claims

1. 1. A lithium ion battery negative electrode composition comprising: Composite particles, each composite particle comprising: The porous carbon includes pores and a Si-containing active material, The Si-containing active material exhibited a thermal conductivity of 10 －１３ torr, At least a portion of the Si-containing active material is trapped in the pores, the weight fraction of the Si-containing active material in the composite particles is 20% by weight to 87% by weight; The porous carbon is N ２ The open pore volume measured by gas is 0.75 cm ３ / g ~ 2.5cm ３ / g of the lithium ion battery negative electrode composition.

2. The Brunauer-Emmett-Teller (BET) specific surface area (SSA) of the composite particles is 0.2 m ２ / g to 100m ２ The lithium ion battery negative electrode composition according to claim 1, wherein the composition is in the range of 1 / g.

3. 2. The lithium ion battery negative electrode composition according to claim 1, wherein the average particle size of the Si-containing active material is in the range of 2 nm to 30 nm.

4. the volume fraction of the pores of the porous carbon exhibits a characteristic dimension in the range of 0.5 nm to 10 nm; 2. The lithium ion battery negative electrode composition according to claim 1, wherein the volume fraction is in the range of 30% by volume to 100% by volume.

5. 10. The lithium-ion battery negative electrode composition of claim 1, wherein the composite particles have a protective surface layer that protects at least a portion of the Si-containing active material.

6. 6. The lithium ion battery negative electrode composition of claim 5, wherein the protective surface layer comprises carbon.

7. 2. The lithium ion battery negative electrode composition of claim 1, wherein the average size of the composite particles is in the range of 200 nm to 20 μm.

8. 8. The lithium ion battery negative electrode composition of claim 7, wherein the average size of the composite particles is 600 nm to 10 μm.

9. 10. The lithium ion battery negative electrode composition of claim 1, wherein the porous carbon is derived from biomass.

10. 10. The lithium ion battery negative electrode composition of claim 9, wherein the biomass-derived porous carbon is derived from one or more of: (i) nut shells, (ii) fruit kernels, (iii) wood, (iv) bamboo, (v) grass, straw or dried leaves, (vi) corn kernels, (vii) sycamore fluff, (viii) natural carbohydrates, or (ix) any combination thereof.

11. the biomass-derived porous carbon is derived at least in part from one or more naturally occurring carbohydrates; 11. The lithium ion battery negative electrode composition of claim 10, wherein the one or more carbohydrates are cellulose, chitin, alginate, sucrose, glucose, starch, or combinations thereof.

12. The biomass-derived porous carbon is derived at least in part from nut shells; 11. The lithium ion battery negative electrode composition of claim 10, wherein the nut shells are selected from coconut shells, apricot shells, almond shells, or combinations thereof.

13. 2. The lithium ion battery negative electrode composition according to claim 1, wherein the average particle size of the Si-containing active material is in the range of 3 nm to 100 nm.

14. 2. The lithium ion battery negative electrode composition of claim 1, wherein 50% to 100% by weight of the Si-containing active material is confined within the pores.

15. The Brunauer-Emmett-Teller (BET) specific surface area (SSA) of the porous carbon is 500 m ２ / g~4400m ２ 10. The lithium ion battery negative electrode composition of claim 1, wherein the SiO2 content is in the range of 0.1 wt. / g.

16. The BET specific surface area of ​​the porous carbon is 800 m ２ / g to 3000m ２ 16. The lithium ion battery negative electrode composition of claim 15, wherein the SiO2 content is in the range of 0.1 wt. / g.

17. 10. The lithium ion battery negative electrode composition of claim 1, wherein the porous carbon contains less than 1 wt. % ash.

18. 10. The lithium ion battery negative electrode composition of claim 1, wherein the porous carbon has a purity of at least 96% by weight.

19. 10. The lithium ion battery negative electrode composition of claim 1, wherein the porous carbon contains less than 10% by weight of hydrogen atoms.

20. 10. The lithium ion battery negative electrode composition of claim 1, configured such that 50% to 100% by volume of the pores remain sealed and inaccessible to electrolyte while the lithium ion battery negative electrode composition is part of a lithium ion battery.

21. A negative electrode containing the lithium ion battery negative electrode composition according to claim 1; A positive electrode and an electrolyte interposed between the negative electrode and the positive electrode.

22. 2. The lithium ion battery negative electrode composition according to claim 1, wherein the weight fraction of the Si-containing active material in the composite particles is 30% by weight to 87% by weight.

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