Biphasic, ternary, and carbon-infused lithium-alloys and freestanding anodes for lithium-based batteries

Abstract

Freestanding, composite anodes include biphasic Li-Mg-X ternary alloys. The composite anodes feature improved Li-ion transport and reduced dendrite formation. Biphasic Li-Mg-X ternary alloyed anodes may be paired with iron phosphate-containing cathodes. The Li may be present in an amount from about 10 wt% to about 90 wt%. The Mg may be present in an amount from about 5 wt% to about 50 wt%. Ternary alloy component(s) may include calcium (Ca), gallium (Ga), boron (B), tin (Sn), aluminum (Al), indium (In), bismuth (Bi), antimony (Sb), tellurium (Te), carbon (C), silicon (Si), bismuth telluride (BiTe), antimony telluride (SbTe), zinc (Zn), etc., in amounts from about 1 wt% to about 90 wt%. The anodes may include lithium-ion conducting material(s): bismuth telluride (BiTe), antimony telluride (SbTe), lithium-doped tritelluride (LiTe3), lithium titanate (Li4Ti5O12, "LTO"), lithium lanthanum zirconium oxide (Li7La3Zr2O12, "LLZO"), lithium phosphide (Li3P), molybdenum oxide (MoO), molybdenum disulfide (MoS2).

Description

BIPHASIC, TERNARY, AND CARBON-INFUSED LITHIUM- ALLOYS AND FREESTANDING ANODES FOR LITHIUM-BASED BATTERIESRELATED APPLICATIONS

[0001] This International Patent Application is being filed pursuant to the Patent Cooperation Treaty (PCT), and claims priority to U.S. Provisional Patent Application Nos. 63 / 664,639, filed June 26, 2024 and entitled “Biphasic, Three Dimensional Lithium- Based Alloys including Ternary Components and Applications Therefor,” 63 / 658,087, filed June 10, 2024 and entitled “Freestanding Lithium-Alloy Anodes For Lithium-based Batteries,” 63 / 616,995, filed January 2, 2024 and entitled “Freestanding Lithium-Alloy Anodes For Lithium-based Batteries,” 63 / 616,412, filed December 29, 2023 and entitled “Biphasic, Three Dimensional Lithium-Based Alloys including Ternary Components and Applications Therefor,” 63 / 616,427, filed December 29, 2023 and entitled “Graphitic Carbon Infused 3D Anode Composite Materials and Applications Therefor,” the contents of each of the foregoing applications arc herein incorporated by reference in entirety.TECHNICAL FIELD

[0002] This disclosure relates generally to batteries, and, more particularly, to lithium-based batteries that can provide high specific energy and energy density combined with long cycle life.BACKGROUND

[0003] Batteries, particularly lithium-based batteries, are susceptible to failure caused by various mechanisms, including breakdown and reformation of solid electrolyte interphase(s) (SEI(s)) that consumes electrolyte, morphological changes that form highly porous structures in the anode, as well as formation of dendritic depositions which may eventually lead to internal short circuiting within the electrochemical cell.

[0004] Li metal anodes in particular experience huge volumetric change during repeated stripping and plating that occurs during normal cycling, due to the intrinsic hostless nature of the anode material. The severe volumetric change further can cause unstable electrode-electrolyte interface, continued side reactions with the electrolyte, and pulverization of the electrode, consequently reducing the stability thereof.

[0005] Meanwhile, Li has the highest oxidation potential of all elements, and can react with almost all species present in electrolyte solutions (including solvents and salts) to form an intricate SEI. The SEI is electronically insulated but ionically conductive to Li+ions so that the reactions between Li metal and electrolyte can be partially blocked. Thus, the SEI provides kinetic protection towards electrolytes that are otherwise thermodynamically reactive.

[0006] However, the SEI is generally non-uniform, which results non-uniform current distribution during plating and can render uneven Li deposition and cracking during cycling, which in turn causes fresh Li metal to be exposed to electrolyte and results in the consumption of active Li material and electrolyte.

[0007] Such localized non-uniform Li deposition can manifest as dendrites, which pose serious problem to the safety and cyclability of Li metal cells. The dendrites can be dislodged from the electrode and form zones of ‘dead’ Li. Furthermore, Li dendrites can penetrate through conventional polyolefin separators or even polymer / solid electrolyte separators, which has been a primary performance detractor for Li metal-based cells.

[0008] The problems noted above are further complicated in Li-S cells, where massive soluble polysulfides are released from the cathode. These polysulfides may detrimentally participate in SEI formation to increase unevenness of the SEI, increase the anode impedance and exacerbate the corrosion of Li metal anode. Consequently, repeated volumetric changes and corrosion continuously consumes active Li and forms massive “dead Li” that is detached from the conductive substrate during cycling, leading to poor recyclability of Li-S batteries.

[0009] Often it is the anode that contributes to cell failure, either via electrolyte consumption, e.g., due to corrosion or depletion thereof during cycling. Such failures are particularly at high current densities which are prevalent in high-energy Li-S pouch cells with dense cathodes, limited electrolyte, and limited anode reservoir (or low N / P).

[0010] Further problems with using Li metal as an anode material relate to the current collector or substrate which is traditionally copper. For Li-S cells, however, the use of Cu substrate for the anode is disadvantageous due to its mass reducing the cell specific energy(higher mass fraction in Li-S cell than in a Li-ion cell) and also possible corrosion of Cu from the poly sulfides.

[0011] A substrate-free, pure Li electrode design might partially address some of the foregoing challenges, but presents significant risks of its own due to the morphological and instability problems of Li anode as described above.

[0012] To address the above issues of unstable Li metal anodes regarding volumetric change and high reactivity toward electrolytes and polysulfides, some have proposed using Li alloys for anodes in Li-S cells. Li can alloy with several metals including silicon, tin, magnesium, and aluminum, with the resulting alloys exhibiting reversible electrochemical activity. Alloy-based anodes will also have higher electrode potential against Li deposition, which can hinder the corrosion reactions with electrolyte components from the thermodynamic point of view. Meanwhile, the alloying element can function as a Li host to mitigate Li volumetric change, further stabilizing the electrode morphology and inhibiting electrode pulverization. The alloy as a whole can form a more stable surface film over the anode, which will reduce the non-uniform deposition of Li.

[0013] However, the use of Li-based alloys as anode material results in a reduction in the specific energy due to reduced capacity, and even voltage in some cases. Moreover, some of the alloy elements tend to undergo consideravle volumetric changes during lithiation and delithation (e.g., Si, Sn and Ge) and therefore are not suitable candidates despite their high theoretical capacity. Further still, the alloys tend to be reversible over a limited range of composition (e.g., Li- Al), with resulting low capacity.

[0014] Moreover, there arc formidable challenges that need to be overcome to maximize the full capability of Li metal and Li-based alloys, particularly as anode active materials in Li-based applications.

[0015] One such challenge relates to the growth of dendritic lithium structures on lithium- based anodes during plating. The dendrites can be dislodged from the electrode, detrimentally forming zones of ‘dead’ Li that reduces the amount of active material available for electrochemical work. Furthermore, Li dendrites can penetrate through conventional polyolefin separators or even polymer / solid electrolyte separators, which has been a primary performance detractor for Li metal-based cells.

[0016] Some groups have attempted to address dendrite formation by including metallic foams in the anode composition, or forming the anode from a metallic foam. Others have similarly approached this problem by including or using free-standing carbon films in or as a three dimensional host for lithium metal. However, these approaches undesirably require addition of significant amounts of inert material, thus reducing the energy density of the resulting battery. Moreover, these techniques are not scalable, and cannot satisfy modem demand for high energy battery systems.

[0017] As such, there is thus a need for addressing these and / or other issues associated with the prior art.SUMMARY

[0018] This summary is provided to introduce in a simplified form a selection of concepts that are further described below in the Detailed Description section. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to limit the scope of the claimed subject matter.

[0019] In some implementations, a composite anode associated with a lithium-based battery includes a Li-Mg-X ternary alloy, a lithium-ion conducting material, and / or an electronically conducting material.

[0020] X refers to the ternary component of the alloy, which may include one or more ternary components in any amount from about 1 wt% to about 90 wt%, e.g., about 1 wt%, about 2.5 wt%, about 3.33 wt%, about 5 wt%, about 6.66 wt%, about7.5 wt%, about 10 wt%, about 12.5 wt%, about 15 wt%, about 20 wt%, about 25 wt%, about 30 wt%, about 33.3 wt%, about 35 wt%, about 40 wt%, about 50 wt%, about 60 wt%, about 66.6 wt%, about 70 wt%, about 75 wt%, about 80 wt%, about 90 wt%, or any value therebetween or subrange in the broader range of about 1 wt% to about 90 wt%, according to various implementations. Moreover, X may include one or more of: calcium (Ca), gallium (Ga), boron (B), tin (Sn), aluminum (Al), indium (In), bismuth (Bi), antimony (Sb), tellurium (Te), carbon (C), silicon (Si), bismuth telluride (BiTe), antimony telluride (SbTe), zinc (Zn), or any combination thereof. Preferably, the one or more ternary components are substantially homogenously distributed throughout a bulk of the composite anode. Moreover, the Li-Mg-X ternary alloy preferably includes a Li- Mg alloy phase and a Li-X alloy phase. A weight ratio of the Li-Mg alloy phase to the Li- X alloy phase is between approximately 0.1 and approximately 20. In more implementations, the lithium-ion conducting material may include: bismuth telluride (BiTe), antimony telluride (SbTe), lithium-doped tritelluride (LiTea), lithium titanate (L TisOia, “LTO”), or lithium lanthanum zirconium oxide (LivLaaZnOn. “LLZO”), lithium phosphide (LLP), molybdenum oxide (MoO), molybdenum disulfide (M0S2), or any combination thereof.

[0021] Similarly, the electron conducting material may include carbon.

[0022] Where the Li-Mg-X alloy includes carbon, the carbon may include: graphite, graphene, carbon nanotubes, hollow porous multi-nanochannel carbon fiber (HTCNF),non-graphitizing carbon, carbon nanofibers, or any combination thereof. Notably, in some aspects the carbon forms an electrochemically inert phase in the Li-Mg-X alloy. The carbon may also be substantially homogenously distributed throughout a bulk of the anode.F0023] In various approaches, a lithium content in the anode is between approximately 10 wt% and approximately 90 wt%, such as about 10 wt%, about 12.5 wt%, about 15 wt%, about 20 wt%, about 25 wt%, about 30 wt%, about 33.3 wt%, about 35 wt%, about 40 wt%, about 50 wt%, about 60 wt%, about 66.6 wt%, about 70 wt%, about 75 wt%, about 80 wt%, about 90 wt%, or any value therebetween or subrange in the broader range of about 10 wt% to about 90 wt%.

[0024] Moreover, a magnesium content in the anode, or in the Li-Mg-X alloy, is preferably a nonzero amount up to approximately 50 wt%, such as about 1 wt%, about 2.5 wt%, about 3.33 wt%, about 5 wt%, about 6.66 wt%, about7.5 wt%, about 10 wt%, about 12.5 wt%, about 15 wt%, about 20 wt%, about 25 wt%, about 30 wt%, about 33.3 wt%, about 35 wt%, about 40 wt%, about 50 wt%, or any value therebetween or subrange in the broader range of greater than about 0 wt% to about 50 wt%.

[0025] Moreover still, an amount of the lithium-ion conducting material may be between approximately 1 wt% and approximately 90 wt%, for example, about 1 wt%, about 2.5 wt%, about 3.33 wt%, about 5 wt%, about 6.66 wt%, about7.5 wt%, about 10 wt%, about 12.5 wt%, about 15 wt%, about 20 wt%, about 25 wt%, about 30 wt%, about 33.3 wt%, about 35 wt%, about 40 wt%, about 50 wt%, about 60 wt%, about 66.6 wt%, about 70 wt%, about 75 wt%, about 80 wt%, about 90 wt%, or any value therebetween or subrange in the broader range of about 1 wt% to about 90 wt%, according to various implementations.

[0026] Accordingly, a weight ratio of the Li-Mg-X alloy to the lithium-ion conducting material is preferably in a range between approximately 1 and approximately 9, or example, a weight ratio of about 1, about 1.25, about 1.33, about 1.5, about 1.66, about 1.75, about 2, about 2.25, about 2.5, about 3, about 3.33, about 4, about 5, about 6, about 6.66, about 7, about 7.5, about 8, about 9, or any value or subrange in the broader range of about 1 to about 9, in various implementations.

[0027] In some approaches, the composite anode may further include alumina (AI2O3) and / or titania (TiCh)

[0028] In some approaches, the composite anode may further include combinations of such materials (e.g.,LTO and titania (TiCE, which is one of our formulations.

[0029] The composite anode may be in the form of a freestanding, three-dimensional monolith.

[0030] In some approaches, the composite anode of claim 1, may additionally include a polymer coating on surface(s) of the anode, the polymer coating including one or more of polyvinylidene fluoride (PVDF), pentaerythritol tetraacrylate (PETEA), polyethylene glycol dimethacrylate (PEGDMA), or any combination thereof. A thickness of the polymer coating may be anywhere in a range from approximately 100 nm to approximately 10 pm, e.g., about 100 nm, about 200 nm, about 250 nm, about 300 nm, about 333 nm, about 400 nm, about 450 nm, about 500 nm, about 600 nm, about 700 nm, about 800 nm, about 900 nm, about 1 pm, about 2 pm, about 3 pm, about 5 pm, about 6.66 pm, about 7.5 pm, about 10 pm, or any value therebetween or subrange in the broader range of about 100 nm to about 10 pm.

[0031] Similarly, a thickness of the composite anode as a whole is approximately 100 pm in accordance with select aspects of the presently described inventive concepts.The composite anode may be part of an electrochemical cell characterized by a coin configuration, a cylindrical configuration, a prismatic configuration, a pouch configuration, or any other suitable configuration as described herein, or equivalents thereof that would be appreciated by those having ordinary skill in the art upon reading the present disclosure. In some approaches, the electrochemical cell neither includes nor is coupled to any distinct structure serving as a current collector other than the three- dimensional (3D) monolith itself.

[0032] In some other aspects, an example anode may further include one or more of alumina (AI2O3) or titania (TiCh). In some instances, the amount of the lithium-ion conducting material in the anode may be between approximately 1 wt% and approximately 90 wt%. In some other instances, the weight ratio of the Li-Mg alloy to the lithium-ion conducting material may be between approximately 1 and approximately 9.In some implementations, the magnesium content in the Li-Mg alloy in a anode may be between approximately 5 wt% and approximately 50 wt%.

[0033] In some implementations, the electron conducting material in the anode may include one or more of carbon, aluminum, or silicon. In some instances, carbon may include graphite.

[0034] In some implementations, an anode associated with a lithium-based battery may include a lithium-magnesium ternary alloy. In some other implementations, a anode associated with a lithium-based battery may include a Li-Al-Mg ternary alloy. In some instances, an aluminum content in a Li-Al-Mg ternary alloy may be between approximately 5 wt% and approximately 20 wt%. In some instances, a Li-Al-Mg ternary alloy may further include any one of the lithium-ion conducting materials or fillers previously described herein.

[0035] In some implementations, an anode associated with a lithium-based battery may include a Li-Si-Mg ternary alloy. In some instances, a silicon content in a Li-Si-Mg ternary alloy may be between approximately 5 wt% and approximately 20 wt%. In some instances, a Li-Si-Mg ternary alloy may further include any one of the lithium-ion conducting materials previously described herein.

[0036] In some other implementations, an anode associated with a lithium-based battery may include a Li-Mg / carbon alloy. In some instances, a carbon content in a Li- Mg / C alloy may be between approximately 1 wt% and approximately 20 wt%. In some instances, a Li-Mg / C alloy may further include any one of the lithium-ion conducting materials, as previously described herein.

[0037] In some implementations, an anode associated with a lithium-based battery may include a biphasic alloy including a Li-Mg alloy phase and a Li-x alloy phase. In some aspects, the Li-x alloy phase may include alloys of lithium and one of calcium, boron, tin, aluminum, indium, bismuth, antimony, or zinc. In some other aspects, the Li-x alloy phase may include a Li2Ca (also referred to herein as CaLi2) alloy phase. In some instances, the weight ratio of the Li-Mg alloy phase to the LiiCa alloy phase may be between approximately 0. 1 and approximately 20.

[0038] In some implementations, a biphasic alloy including a Li-Mg alloy phase and a Li Ca alloy phase may be characterized by a lithium content of between approximately 55 wt% and approximately 75 wt%, a magnesium content of between approximately 15 wt% and approximately 30 wt% and a calcium content of between approximately 2 wt% and approximately 30 wt%.

[0039] In some implementations, any one of the anodes described herein may include a polymer coating including one or more of poly vinylidene fluoride (“PVDF”), pentaerythritol tetraacrylate (“PETEA”) or polyethylene glycol dimethacrylate (“PEGDMA”) disposed on the anode. The thickness of the anode may be approximately 100 pm. The thickness of the polymer coating may be between approximately 1 pm and approximately 10 pm.

[0040] In some implementations, a lithium-based battery may include any one of the anodes disclosed herein and a fluorinated ether electrolyte including approximately 50:25:25 (vol%) 1,2-dimethoxyethane (“DME”): 1,3-dioxolane (“DOL”): bis (2,2,2- trifluoroethyl) ether (“BTFE”) and including approximately 0.4 M lithium bis (trifluoromethanesulfonyl) (LiTFSI) and approximately 2 wt% Li NO?. In some instances, an anode associated with a lithium-based battery may include a anode including a Li-Mg alloy and one or more of a lithium-ion conducting material or an electron conducting material.

[0041] In some implementations, the fluorinated electrolyte in a Li-S battery including any one of the anodes described herein may include approximately 50:25:25 (vol%) DME : DOL: 1,1,2,2-tetraethoxyethane (“TEE”) and including approximately 0.4 M LiTFSI and approximately 2 wt% Li NO?.

[0042] In some implementations, the fluorinated electrolyte in a Li-S battery including any one of the anodes described herein may include approximately 50:25:25 (vol%) DME : DOL: 1 , 1 ,2,2-tetrafluoroethyl 2,2,2-trifluoroethyl ether (“TFETFE”) and including approximately 0.4 M LiTFSI and approximately 2 wt% LiNO?.

[0043] In some implementations, the fluorinated electrolyte in a Li-S battery including any one of the anodes described herein may include approximately 60:20: 10:10(vol%) DME : DOL: TEE: TFETFE and including approximately 0.4 M LiTFST and approximately 2 wt% Li NO ;.

[0044] In some implementations, the fluorinated electrolyte in a Li-S battery including any one of the anodes described herein may include approximately 50:25:25 (vol%) DME : DOL: l,l,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (“TTE”) and including approximately 0.4M LiTFSI and approximately 2 wt% LiNO;.

[0045] In some implementations, the fluorinated electrolyte in a Li-S battery including any one of the anodes described herein may include approximately 50:25:25 (vol%) DME : DOL: 1 fluorinated 1,4-dimethoxylbutane (“FDMB”) including approximately 0.4 M LiTFSI and approximately 2 wt% LiNO;.

[0046] In some implementations, the fluorinated electrolyte in a Li-S battery including any one of the anodes described herein may include approximately 1.0 M LiTFSI in approximately 50:50 (vol%) DOL: BTFE.

[0047] In some implementations, an example lithium-based battery may include a cathode disposed opposite to any one of the anodes described herein. In some implementations, an example cathode may include one or more porous carbon layers including porous carbon agglomerates of porous carbon primary nanoparticles, wherein a respective porous carbon primary nanoparticle may include an inner porous shell disposed about a center of the respective porous carbon primary nanoparticle and enclosing an inner porous carbon region, an outer porous shell enclosing an outer porous carbon region disposed between the inner shell and the outer shell, and an interconnected porous network disposed in and in fluid communication with the inner and outer porous carbon regions.

[0048] In some aspects, the inner carbon region and the outer carbon region of example porous carbon primary nanoparticles may be characterized by an average pore size and an average pore density associated with each region. In some other aspects, the average pore size may decrease along a radial direction from the center to the outer porous shell.

[0049] In some instances, an example porous carbon primary nanoparticle may further include one or more intermediate porous shells disposed between the inner porousshell and the outer porous shell, wherein each of the intermediate porous shells encloses a respective intermediate porous carbon region.

[0050] In some aspects, the porous carbon agglomerates may be characterized by a Raman spectroscopy signature with an ID / IG ratio between approximately 0.95 and approximately 1.05. In some other aspects, the porous carbon agglomerates may be characterized by a Brunauer-Emmett-Teller (“BET”) surface area between approximately 50 m2 / g and 300 m2 / g measured using nitrogen gas. In some aspects, the porous carbon agglomerates may be characterized by an electrical conductivity of between approximately 500 S / m and 20,000 S / m when compressed at a pressure of approximately 12,000 pounds per square inch (psi).

[0051] In some implementations, an example cathode associated with a lithium-based battery may include porous carbon agglomerates of porous carbon primary nanoparticles, which include one or more interconnected bundles of electrically conductive graphene layers. In some aspects, the graphene layers may be arranged as one or more stacks connected to each other and defining a 3D porous scaffold structure including mesopores. In some other aspects, the one or more stacks may be disposed substantially orthogonal to each other. In some instances, the graphene layers may be characterized by a linear dimension of between approximately 50 nm and approximately 200 nm. In some other instances, the graphene layers may include one or more of single layer graphene (“SLG”), few layer graphene (“FLG”), or many layer graphene (“MLG”). In some aspects, the porous carbon agglomerates may be characterized by an electrical conductivity of between approximately 500 S / m and 20,000 S / m when compressed at a pressure of approximately 12,000 pounds per square inch (psi).

[0052] In some implementations, the geometrical shape of any one of the Li-S batteries previously described may be cylindrical. The cylindrical battery may be approximately 18 mm in diameter and approximately 65 mm in length. In some implementations, the cylindrical battery may be approximately 21 mm in diameter and approximately 70 mm in length. In some implementations, the cylindrical battery may be approximately 46 mm in diameter and approximately 80 mm in length.

[0053] Details of one or more implementations of the subject matter described in this disclosure are set forth in the accompanying drawings and the description below. Otherfeatures, aspects, and advantages will become apparent from the description, the drawings, and the claims. Note that the relative dimensions of the following FIGS, may not be drawn to scale.BRIEF DESCRIPTION OF THE DRAWINGS

[0054] FIG. 1 shows a plot illustrating cathode discharge capacity of example lithium-based coin cells including freestanding Li-Mg alloy anodes of varying Li-Mg compositions, according to some implementations.

[0055] FIG. 2A shows an example X-ray diffraction (XRD) pattern of a biphasic freestanding anode alloy including a Li-Mg alloy phase and a LiiCa alloy phase, according to some implementations.

[0056] FIG. 2B shows a scanning electron microscopy (SEM) micrograph of a cross section of an example biphasic freestanding anode alloy including a Li-Mg alloy phase and a LiiCa alloy phase, according to some implementations.

[0057] FIG. 2C shows another SEM micrograph of an example biphasic freestanding anode alloy including a Li-Mg alloy phase and a Li Ca alloy phase, according to some implementations.

[0058] FIG. 3A shows a scanning electron microscopy (SEM) micrograph of a cross section of an example biphasic freestanding anode alloy including a Li-Mg alloy phase and a LiiCa alloy phase, according to some implementations.

[0059] FIGS. 3B-3C show SEM-energy dispersive X-ray spectroscopy (EDS) elemental dispersion images of an example biphasic freestanding anode alloy including a Li-Mg alloy phase and a Li^Ca alloy phase, according to some implementations.

[0060] FIG. 4A shows voltage profiles of example lithium-based half cells including a freestanding composite anode including a Li-Mg alloy and lithium titanate (“LTO”), according to some implementations.

[0061] FIGS. 4B-4C show SEM images and SEM-EDS elemental dispersion images of an example Li-Mg alloy anode and a freestanding composite anode including Li-Mg alloy / LTO, respectively, according to some implementations.

[0062] FIG. 5A shows a schematic diagram of an example porous carbon primary nanoparticle, according to some implementations.

[0063] FIG. 5B shows a transmission electron microscopy (TEM) image showing aggregates of porous carbon primary nanoparticles, according to some implementations.

[0064] FIG. 5C shows a TEM image of agglomerates of porous carbon primary nanoparticlcs, according to some implementations.

[0065] FIG. 5D shows a TEM image of surface etched agglomerates of porous carbon primary nanoparticles, according to some implementations.

[0066] FIG. 5E shows a schematic diagram of another example porous carbon primary nanoparticle, according to some implementations.

[0067] FIG. 6A shows a schematic diagram of agglomerates of porous carbon primary nanoparticles, according to some implementations.

[0068] FIG. 6B shows a scanning electron microscopy (SEM) micrograph of agglomerates of porous carbon primary nanoparticles, according to some implementations.

[0069] FIG. 6C shows a TEM micrograph of agglomerates of porous carbon primary nanoparticles, according to some implementations.

[0070] FIG. 7 shows a schematic diagram depicting an example lithium-based cylindrical battery, according to some implementations.

[0071] FIG. 8A shows a plot illustrating cathode discharge capacity of lithium-based coin cells including biphasic freestanding anodes including a Ei-Mg alloy phase and a EiaCa alloy phase, according to some implementations.

[0072] FIG. 8B shows another plot illustrating cathode discharge capacity of lithium- based coin cells including biphasic freestanding anodes including a Ei-Mg alloy phase and a Li2Ca alloy phase, according to some implementations.

[0073] FIG. 9A shows a plot illustrating the rate capability test performance of lithium-based symmetric cells including a freestanding composite anode including a Li- Mg alloy and LTO, according to some implementations.

[0074] FIG. 9B shows a plot illustrating corrosion current after lithium stripping measured using lithium symmetric cells including a freestanding composite anode including a Li-Mg alloy and LTO, according to some implementations.

[0075] FIG. 9C shows a plot illustrating corrosion current after lithium plating measured using lithium symmetric cells including a freestanding composite anode including a Li-Mg alloy and LTO, according to some implementations.

[0076] FIG. 10A shows a plot illustrating cathode discharge capacity of lithium- based coin cells including a freestanding composite anode including a Li-Mg alloy and LTO, according to some implementations.

[0077] FIG. 10B shows plots which respectively depict discharge capacity, capacity retention, and Coulombic Efficiency of an exemplary Li-Mg / LTO alloy relative to baseline Li-Mg.

[0078] FIG. 10C shows plots illustrating the specific capacity and Coulomibic efficiency of several exemplary Li-Mg / LTO formulations with varying magnesium amount, as compared to baseline Li-Mg.

[0079] FIG. 10D shows several SEM images of an Li-Mg anode surface and a 3D Li- Mg-LTO anode surface following the first stripping and plating cycles, according to one implementation.

[0080] FIGS. 11A-11B show plots illustrating cathode discharge capacity and capacity retention of lithium-based coin cells including a freestanding Li-Al-Mg ternary alloy anode, according to some implementations.

[0081] FIGS. 12A-12C show plots illustrating cathode discharge capacity, capacity retention, and Coulombic efficiency of lithium-based coin cells including a freestanding Li-Si-Mg ternary alloy anode, according to some implementations.

[0082] FIGS. 13A-13F show plots illustrating cathode discharge capacity, capacity retention, polarization, and Coulombic efficiency of lithium-based coin cells including a freestanding Li-Mg / C alloy anode, according to some implementations.

[0083] FIG. 14A shows a simplified schematic cross-sectional view of an electrochemical cell characterized by a pouch cell arrangement, according to one embodiment of the presently disclosed inventive concepts.

[0084] FIG. 14B is a simplified schematic external view of the electrochemical cell shown in FIG. 14A, according to one embodiment of the presently disclosed inventive concepts.

[0085] FIG. 14C depicts a simplified schematic of the pouch cell arrangement shown in FIG. 14B, wrapped into a jelly-roll configuration, according to one approach of the presently disclosed inventive concepts.

[0086] FIG. 15A is a simplified schematic of an electrochemical cell characterized hy a coin cell arrangement, according to one implementation of the presently disclosed inventive concepts.

[0087] FIG. 15B depicts various components of the coin cell arrangement shown in FIG. 15 A, according to a simplified schematic exploded view.

[0088] FIG. 16A is a simplified schematic of an electrochemical cell characterized by a cylindrical cell arrangement, according to one aspect of the presently disclosed inventive concepts.

[0089] FIG. 16B is a simplified schematic cut-out view of exemplary components of the cylindrical cell arrangement shown in FIG. 16A, according to one implementation of the presently disclosed inventive concepts.

[0090] FIG. 17 is a simplified schematic of an electrochemical cell characterized by a cylindrical cell arrangement, according to one aspect of the presently disclosed inventive concepts.

[0091] FIG. 18 is a chart showing various forms of carbonaceous material, and methods of producing the same from elemental carbon (e.g., charcoal), which may be included in various components of electrochemical cells such as shown in the foregoing FIGS.

[0092] Like reference numbers and designations in the various drawings indicate like elements.DETAILED DESCRIPTION

[0093] The following description is directed to some example implementations for the purpose of describing the innovative aspects of this disclosure. However, a person having ordinary skill in the art will readily recognize that the teachings herein can be applied in a multitude of different ways. The described implementations can be implemented in batteries for a variety of applications and may be tailored to compensate for various performance related deficiencies. As such, the disclosed implementations are not to be limited by the examples provided herein, but rather encompass all implementations contemplated by the attached claims. Additionally, well-known elements of the disclosure will not be described in detail or will be omitted so as not to obscure the relevant details of the disclosure.

[0094] Various aspects of the novel compositions and methods are described more fully herein with reference to the accompanying drawings. These aspects are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. Although some examples and aspects are described herein, many variations and permutations of these examples fall within the scope of the disclosure. Although some benefits and advantages of the various aspects are mentioned, the scope of the disclosure is not intended to be limited to benefits, uses, or objectives. The detailed description and drawings are merely illustrative of the disclosure rather than limiting, the scope of the disclosure being defined by the appended claims and equivalents thereof.

[0095] In this disclosure, a primary carbon nanoparticle may be considered as a spheroidal shaped, non-discreet component or building block of an aggregate, separable from the aggregate only by fracturing. A plurality of primary carbon nanoparticles produced by one or more methods including thermal cracking of a hydrocarbon gas, may be coalesced, or joined to form aggregates of primary carbon nanoparticles. A carbon aggregate may be considered as a discrete, colloidal entity that is the smallest dispersible unit, composed of coalesced primary carbon nanoparticles. The primary carbon nanoparticles may be connected together by one or more of van der Waals forces, covalent bonds, ionic bonds, metallic bonds, or by other physical or chemical interactions. A plurality of aggregates may be considered as an agglomerate.Agglomerates of primary carbon nanoparticles may be produced from one or more methods including thermal cracking of a hydrocarbon gas. An example porous carbon agglomerate of primary carbon nanoparticles may be characterized by a principal dimension of at least approximately 1 pm.10096] In this disclosure, “graphene” refers to an allotrope of carbon in the form of atomic-scale, hexagonal lattice in which one atom forms each vertex. The carbon atoms in graphene may be sp2hybridized carbon atoms. Additionally, graphene has a Raman spectrum with two main peaks: a G-mode at approximately 1580 cm'1and a D mode at approximately 1350 cm'1(when using a 532 nm excitation laser). As used herein, carbonaceous materials may refer to materials containing or formed of one or more types or configuration of carbon.

[0097] Commercialization of lithium-based (“Li-S”) batteries has been hampered by limited discharge / charge cycling of less than approximately 100 cycles. Root cause analysis suggests that Li-metal anode failure is a primary reason for cell failure. During cycling, the Li-metal anode experiences significant volume change caused by repeated stripping (during discharge) and plating (during charge) of lithium. This volume change negatively impacts anode stability, and in particular, the stability of unsupported (or freestanding) Li-metal anodes. In a freestanding Li-metal anode, the anode is not supported on a metal substrate such as a copper current collector. Anode stability is further impacted by an unstable electrode-electrolyte interface and pulverization of the anode caused by volume changes during cycling, because lithium has a high oxidation potential (approximately 3.04V) and can react with almost any electrolyte solution, either with thesolvent or the salt, to form a solid electrolyte interphase (“SEI”) layer.

[0098] The SEI layer is electronically insulating but ionically conductive to Li+ions. As such, once the SEI layer is formed, additional undesirable reaction between the Li- metal anode and electrolyte may be blocked or partially blocked by the SEI layer. However, the SEI layer is generally non-uniform, which results in non-uniform current distribution during plating, and may cause uneven (or non-uniform) lithium deposition and anode cracking during cycling. Fresh lithium metal-anode may be exposed to the electrolyte resulting in the undesirable consumption of lithium for re-formation of the SEI layer. The localized non-uniform lithium deposition and stripping may manifest asdendrites during plating and pits during stripping at the anode during charge / discharge cycles. Dendrites may cause serious safety problems and reduce the cyclability of lithium-ion batteries. Additionally, dendrites may be dislodged from the anode to form ‘dead’ zones of lithium. Lithium dendrites may penetrate through polyolefin separators or even polymer / solid electrolyte separators disposed between the anode and the cathode of a battery, and negatively impact the safety and performance of Li-ion batteries.

[0099] The above problems are further exacerbated in lithium-based batteries (as understood herein, lithium-based batteries include electrochemical cells that utilize lithium, alloys thereof, composites thereof, etc. as an active material in the electrode(s) thereof, especially those electrochemical cells for which lithium is a primary, principal, or essential component thereof), particularly Li-S batteries, which include sulfur confined in a porous carbon cathode as the active cathode material. Sulfur reacts with lithium ions forming poly sulfides. During the discharge cycle, Li ions migrate from the anode to the cathode through the electrolyte where sulfur is reduced to lithium sulfide (Li2S). The sulfur reduction to Li2S is complex and may involve the formation of several intermediate Li polysulfides (Li2Sx, 8 < x < 1). Polysulfides (“Li-PS”) may be formed during the battery discharge cycle as:S8Li2S8Li2S6Li2S4Li2S3^ Li2S2^ Li2S

[0100] Ideally, the Li-PS compounds oxidize back to sulfur during the charge cycle. In practice, Li-PS compounds leak out from the porous carbon cathode as they are highly soluble in the electrolyte, which results in loss of sulfur and reduction in cathode capacity. While sulfur and LLS are relatively insoluble in most electrolytes, many intermediate polysulfides (“Li-PS”) are soluble and cause irreversible loss of active sulfur from the cathode. To minimize the saturation effects from dissolution of Li-PS in the electrolyte, a large amount of electrolyte (E / S > 3) is required, which reduces battery specific energy. The higher polysulfides (Li2S8and Li2Sfi) may diffuse to the anode and may get reduced to lower polysulfides (Li2Se and Li2S4), which subsequently get reoxidized at the cathode. At the anode, the polysulfides participate in SEI formation, increase the unevenness of SEI, increase anode impedance and aggravate the corrosion of the Li metal anode. This cyclic process commonly known as the “polysulfideshuttle”results in poor coulombic efficiency, and progressive leakage of active sulfur material from the cathode which also reduces the life cycle of the battery. Further, the conversion of elemental sulfur to Li2Sxsulfur compounds is accompanied by large volumetric expansion at the cathode (which could be as high as 80%), which subjects the cathode to significant mechanical stresses resulting in rapid cathode degradation.

[0101] Additionally, the “shuttle effect” is responsible for self-discharge of Li-S batteries, because of the slow dissolution of Li-PS during battery dormancy. Battery selfdischarge reduces battery life and causes safety issues. The repeated volume change and the corrosion reactions at the anode continuously consume active Li and form massive “dead Li,” which may be detached during cycling, leading to poor recyclability of Li-S battery. As previously noted, often the anode contributes to cell failure, either via electrolyte consumption of Li due to corrosion or its depletion during cycling. These challenges limit the commercial viability of high-specific energy Li-S batteries having dense cathodes, limited electrolyte, and limited anode capacity (or low N / P ratio). The N / P ratio may be defined as the ratio of reversible capacity (mAh) of the negative electrode (anode) to that of the positive electrode (cathode) assuming complete utilization of sulfur.

[0102] Accordingly, to mitigate the loss of conductivity due to dissolved Li-PS an excess amount of electrolyte is used in Li-S batteries. Additionally, to mitigate lithium- metal loss due to SEI formation, pitting, and dendrite formation, an excess of lithium- mctal is required at the anode. These requirements frustrate attempts to reach or exceed the specific energy target of 500 W-h / kg in Li-S batteries. Li-S batteries generally require an electrolyte to sulfur ratio (“E / S ratio”) of approximately 5 pL / mgS, and a N / P ratio of greater than 2. For comparison, the N / P ratio in commercial Li-ion batteries is between approximately 1.03 and 1.2. While the N / P ratio is important to offset the likely higher loss of anode material during cycling, the areal capacity (mAh / cm2) is also critical to reduce the current density and hence failure rate on the anode.

[0103] Li-S anodes generally use a current collector such as copper as an anode support. Copper adds significant weight to Li-S batteries and reduces the specific energy of the battery. Copper is also susceptible to corrosion by polysulfides. Accordingly, there is significant interest in developing substrate-free or freestanding anodes. However,freestanding anode in Li-S batteries is challenging due to the morphological and instability issues with the lithium- metal (100% lithium) anode. Freestanding anode alloy compositions that are stable under cyclic conditions in Li-S batteries and at low E / S ratios of approximately less than or equal to 5 for coin cells, and less than or equal to 3 for pouch cells are needed. Freestanding anode compositions that are stable under cyclic conditions in Li-S batteries and at N / P ratios of approximately less than 2 to realize battery specific energy of 500 W-h / kg are also needed.

[0104] In some implementations, Li-alloys may be used as freestanding anodes instead of pure-lithium metal anodes to overcome the previously described anode instability issues related to volume change during cycling, and the high reactivity of the Li-metal anodes with the electrolyte and with poly sulfides. Lithium may alloy with several metals including one or more of silicon, tin, magnesium, or aluminum. Li-alloy anodes may be characterized by higher electrode potential compared to lithium and may hinder corrosion at the anode caused by reactions between the anode and polysulfides and electrolytes. Meanwhile, the alloying element may function as a lithium host for lithium deposition or plating (during the charge cycle) absorb volume changes during cycling and help to stabilize the anode. The alloying element may form a stable surface film over the anode, which may reduce the non-uniform deposition of lithium during plating.

[0105] Some alloying elements with lithium may reduce the capacity of Li-S batteries, and subsequently reduce battery specific energy (W-h / kg). Additionally, some alloying elements, for example, silicon (Si), tin (Sn), and germanium (Ge), may undergo severe volume changes during lithiation (plating, during charge cycle) and de-lithiation (stripping during discharge) and may not be suitable candidates for a Li-S battery anode. With elements such as silicon and tin, lithium may form intermetallic compounds of the type LixMy, which have a high degree of ionic bonding, and as such, are brittle, and fragile. Some other lithium alloys such as lithium-aluminum alloys are reversible only over a limited composition range and may not be suitable for Li-S battery use.

[0106] In some implementations, alloying lithium with small amounts of magnesium (Mg) may improve the stability of Li-S battery anodes to reactions with the electrolyte and polysulfides and increase battery cycle life. In lithium-magnesium (“Li-Mg”) alloy anodes, the magnesium alloying element may provide structural integrity to the anodeduring volume changes associated with battery cycling, because magnesium does not undergo stripping and plating at the anode. Additionally, alloying lithium with small amounts of magnesium permits a free-standing anode design (without the need for a copper current collector substrate), which also increases battery specific energy. roio7i Li and Mg have comparable atomic radii and form an extended single solid phase (body centered cubic structure or BCC) alloy over a wide composition range of approximately 11.5-100 wt% lithium in Li-Mg alloys. Therefore, the capacity of a Li-Mg alloy anode may be tuned over a broad range free of any alloy phase change considerations. The Li-Mg alloy may provide a scaffold- like structure, which may facilitate insertion and removal of Li+ions during the chargc / dischargc cycling of a Li-S battery. The volume change related to the insertion of one mole of Li into Mg may be approximately 80% as calculated using Li-Mg alloy lattice parameters, which is much lower than the volume change related to the interaction of lithium with other alloying elements such as silicon, tin, and antimony. Li-Mg alloys are very ductile, which permit straightforward fabrication of electrodes by rolling and annealing. At Li-rich compositions of approximately 90%, no loss in battery voltage may be observed when replacing a Li-anode (100% lithium) with a Li-Mg anode, because lithium stripping and plating may occur close to 0 V. Additionally, as magnesium is lithiophilic, dispersed magnesium in Li-Mg anodes may serve as nucleation sites for uniform lithium deposition during the charge cycle.

[0108] Since Li-Mg alloy anodes form relatively stable SEI interface (compared to Li-anodes), a comparatively smooth anode surface morphology may be realized during the cyclic operation of a Li-S battery. Additionally, a Li-Mg alloy matrix, poor in lithium, and with high electric and ionic conductivity, may be formed after Li stripping to provide an excellent anode current collector and host for subsequent Li plating. Accordingly, Li- Mg alloy anodes may be freestanding and may not require a separate anode current collector.

[0109] As previously described, lithium has a high oxidation potential (of approximately 3.04V) and can react with almost any electrolyte solution, either in a solvent or in a salt form, to form a solid electrolyte interphase (“SEI”) layer. Lithium anode stability is further impacted by an unstable electrode-electrolyte interface andpulverization of the anode caused by volume changes during cycling. Alloying lithium with metals including magnesium may improve the stability of the anode in lithium-based cells, but this increased stability often requires an increase in the number of formation cycles required to reach a target cathode discharge capacity. ronoi FIG. 1 shows a plot 100 illustrating cathode discharge capacity of example lithium-based coin cells including freestanding Li-Mg alloy anodes of varying Li-Mg compositions, according to some implementations. Tests were conducted at C / 3 charge / discharge rate after initial formation (also referred to herein as activation) cycles at a C / 20 rate for 2 cycles followed by a C / 10 rate for 1 cycle. The Mg content in the Li- Mg alloys was between approximately 10 wt% and approximately 28 wt%. The thickness of the Li-Mg freestanding alloy anodes was approximately 100 pm. The cathode loading was approximately 7.5 mg / cm2. The cathode capacity in each case was approximately 4 mAh / cm2. A Celgard PP2075 separator was disposed between the cathode and anode. The anodes did not include any polymeric material coating. The electrolyte included approximately 50:25:25 (vol%) 1,2-dimethoxyethane (“DME”): 1,3-dioxolane (“DOL”): bis (2,2,2-trifluoroethyl) ether (“BTFE”) and including approximately 0.4 M lithium bis (trifluoromethanesulfonyl) imide (“LiTFSI”) and approximately 2 wt% LiNCL. The electrolyte-to-sulfur (“E / S”) ratio was approximately 5.

[0111] Referring to FIG. 1, initial cathode discharge capacity at C / 20 rate decreased as the Mg content in the Li-Mg alloy anodes increased beyond 12 wt%. With the 72Li- 28Mg alloy anode (72 wt% Li and 28 wt% Mg), initial discharge capacity measured was less than 200 mAh / g, which is a 3x decrease in initial discharge capacity over the discharge capacity measured using the 90Li-10Mg alloy anode. With repeated formation cycles, the cells including the 85Li-15Mg alloy anode produced a discharge capacity comparable to that of the 90Li-10Mg anode. This extended formation cycling including approximately 25 cycles is not practical for several applications. Prolonged formation cycling through 40 cycles of cells including 72Li-28Mg alloy anode did not significantly increase the discharge capacity. As such, increased anode stability in Li-Mg alloy anodes may be realized at the expense of discharge capacity and formation cycling time. There is a need to realize improved anode stability with high discharge capacity of approximately 600 mAh / g and at formation cycles of less than approximately 5.

[0112] In some implementations, a freestanding anode associated with a lithium- based battery may include a biphasic alloy including a Li-Mg alloy phase and a Li-x alloy phase. In some aspects, the Li-x alloy phase may include alloys of lithium and one of calcium, boron, tin, aluminum, indium, bismuth, antimony, or zinc. In some other aspects, the Li-x alloy phase may include a LiiCa (also referred to herein as CaLi2) alloy phase. In some instances, the weight ratio of the Li-Mg alloy phase to the LiaCa alloy phase may be between approximately 0.1 and approximately 20.

[0113] In some implementations, a biphasic alloy including a Li-Mg alloy phase and a LiiCa alloy phase may include a lithium content of between approximately 55 wt% and approximately 75 wt%, a magnesium content of between approximately 15 wt% and approximately 30 wt% and a calcium content of between approximately 2 wt% and approximately 30 wt%. Cathode discharge capacity of example lithium-based coin cells including a freestanding dual phase alloy anode including a Li-Mg alloy phase and a LioCa alloy is discussed below under Example 1.

[0114] FIG. 2A shows an example X-ray diffraction (“XRD”) pattern 200A of a biphasic freestanding anode alloy including a Li-Mg alloy phase and a LioCa alloy phase, according to some implementations. The elemental composition of the example biphasic anode alloy was approximately 55 wt% Li, approximately 17 wt% Mg and approximately 28 wt% Ca. As can be seen, the XRD pattern 200A confirms the presence of a Li-Mg alloy phase with a characteristic peak corresponding to the (110) plane based on the reference XRD fingerprint of the 90 wt% Li - 10 wt% Mg alloy (“90Li-10Mg reference”, middle pane), as indicated by the arrow pointing to said peak in the sample and reference. Additionally, the XRD pattern 200A confirms the presence of a Li2Ca alloy phase with a fingerprint corresponding to the (100), (002), (101), (102), (110), (103), (200) and (112) planes based on the reference XRD fingerprint of the Li2Ca alloy (“Li2Ca reference”, bottom pane), as indicated by the circled peaks.

[0115] FIG. 2B shows a scanning electron microscopy (“SEM”) micrograph 200B of a cross section of an example biphasic freestanding anode alloy including a Li-Mg alloy phase and a Li2Ca alloy phase, according to some implementations. The elemental composition of the example biphasic anode alloy was approximately 55 wt% Li,approximately 17 wt% Mg and approximately 28 wt% Ca. As can be seen, discrete Li2Ca alloy 201 is dispersed in the Li-Mg alloy matrix.

[0116] FIG. 2C shows another SEM micrograph 200C of an example biphasic freestanding anode alloy including a Li-Mg alloy phase and a LiiCa alloy phase, according to some implementations. SEM micrograph 200C was collected in the backscattered electron mode. As can be seen, Li2Ca alloy 201 is uniformly dispersed in the Li-Mg alloy matrix. These observations corroborate the XRD pattern of a biphasic alloy (referring to FIG. 2A) and confirm the presence of a dual alloy phase including a Li-Mg alloy phase and a Li2Ca alloy phase in the example freestanding anode. Those skilled in the ail will appreciate that the micrographs are shown by way of example only, and that other scales may exist without departing from the scope and spirit of the present implementations.

[0117] FIG. 3A shows a scanning electron microscopy (SEM) micrograph 300A of a cross section of an example biphasic freestanding anode alloy including a Li-Mg alloy phase and a Li^Ca alloy phase, according to some implementations. FIGS. 3B-3C show SEM-EDS elemental dispersion images 3OOB-3OOC of an example biphasic freestanding anode including a Li-Mg alloy phase and a Li2Ca alloy phase, according to some implementations. The elemental composition of the example biphasic anode alloy was approximately 55 wt% Li, approximately 17 wt% Mg and approximately 28 wt% Ca. Similar to micrograph 200A (referring to FIG. 2A), micrograph 300A shows the dispersion of Li2Ca alloy in the Li-Mg alloy matrix. The elements examined during EDS analysis included magnesium (shown in EDS image 300B, K line) and calcium (shown in elemental dispersion image 300C, K line). Referring to FIG. 3C, the discrete and substantially uniform distribution of calcium suggests no cross-contamination between the biphasic alloys Li-Mg and Li2Ca. Additionally, the biphasic alloys were produced at approximately 300 °C, which is much lower than the formation temperature of at least approximately 400 °C for a Mg-Ca alloy. As such, the above observations indicate that calcium is present as Li2Ca alloy 301. The biphasic alloy including Li-Mg alloy phase and a Li2Ca alloy phase is also substantially free of any unalloyed calcium. The uniform distribution of Mg (referring to FIG. 3B) suggests that the Li2Ca phase is distributed in the Li-Mg alloy phase in the dual phase anode alloy.

[0118] In some implementations, any of the biphasic freestanding anode alloys previously disclosed herein may include a polymer coating including one or more of polyvinylidene fluoride (“PVDF”), pentaerythritol tetraacrylate (“PETEA”) or polyethylene glycol dimethacrylate (“PEGDMA”), or any combination thereof, disposed on the freestanding anode. The thickness of the coating layer may be between approximately 10 nm and approximately 10 pm.

[0119] In some other implementations, a lithium-based battery target of high cathode discharge capacity (for example, approximately 600 mAh / g) may be realized without sacrificing anode stability and cell formation cycle time using a Li-Mg alloy composite anode. In some implementations, a freestanding composite anode associated with a lithium-based battery may include a Li-Mg alloy and a lithium-ion conducting material. In some aspects, the lithium-ion conducting material (also referred to herein as lithium- ion conductive fillers) may include lithium phosphide (LLP), bismuth telluride (BiTe), antimony telluride (SbTe), lithium-doped tritelluride (LiTc?). lithium titanate (Li4TisOi2, “LTO”), lithium lanthanum zirconium oxide (LLLtoZnOi . “LLZO”), molybdenum oxide (MoO), molybdenum disulfide (M0S2), or any combination thereof. In some other aspects, an example freestanding Li-Mg alloy composite anode may further include one of alumina (AI2O3) or titanium dioxide (TiCh). In some instances, the amount of the lithium-ion conducting material in the freestanding Li-Mg alloy composite anode may be between approximately 1 wt% and approximately 90 wt%. In some other instances, the weight ratio of the Li-Mg alloy composite anode to the lithium-ion conducting material may be between approximately 1 and approximately 9. Cathode discharge capacity of example lithium-based coin cells including a freestanding dual phase alloy anode including a Li-Mg alloy phase and a Li2Ca alloy is discussed below under Example 3. Without being bound by any particular theory the lithium-ion conducting fillers may help in controlling the grain size of Li-Mg in the Li-Mg alloy and facilitate lithium-ion diffusion across grain boundaries.

[0120] FIG. 4A shows voltage profiles 400A of example lithium-based half cells including a freestanding composite anode including a Li-Mg alloy and lithium titanate (“LTO”), according to some implementations. The voltage profiles of the half cells with freestanding Li-Mg alloy anode and Li-Mg alloy / LTO composite anode were measured atcharging current of 0.2 mA / cnr and discharge current of 1 .3 mA / cm2. A copper foil was used as the cathode. A glass fiber (GF / A) separator was used between the cathode and anode. The anode did not include any polymeric material coating. The electrolyte included approximately 50:25:25 (vol%) DME: DOL: BTFE and including approximately 0.4 M LiTFSI and approximately 2 wt% Li NO;. As shown in FIG. 4A, with one discharge / charge cycle at C / 3 rate, the charge / discharge profiles of the symmetric cell including the Li-Mg alloy / LTO composite anode was flatter than that measured using the Li-Mg alloy anode.

[0121] FIGS. 4B-4C show SEM images and SEM-EDS elemental dispersion images 400B-400C of an example Li-Mg alloy anode and freestanding composite anode including Li-Mg alloy / LTO, respectively, according to some implementations. The Li- Mg alloy anode sample and Li-Mg alloy / LTO composite anode sample corresponding to the tests associated with FIG. 4A were examined under SEM-EDS imaging. Refening to FIG. 4B, the Li-Mg alloy anode shows a Li-rich layer 401 disposed on a and a Li-Mg alloy layer 402. This stratified gradation in Li-Mg alloy composition could negatively impact anode stability. The EDS analysis targeted magnesium (K line). In contrast, referring to FIG. 4C, the Li-Mg alloy / LTO composite anode showed uniform Mg distribution suggesting stripping and plating of lithium. This result suggests that Li-Mg alloy / LTO composite anode could favor improved anode stability compared to the Li-Mg alloy anode.

[0122] In some implementations, lithium-based batteries including freestanding composite Li-Mg alloy anodes may be subject to sluggish activation that requires several activation cycles to achieve rated discharge capacity. In some instances, prolonged activation may be observed when the Mg content in Li-Mg alloys is greater than approximately 10 wt%. Prolonged battery activation is not suitable for commercial lithium-based battery applications. To mitigate sluggish activation, Li-Mg alloys may include one or more of lithium-ion conducting fillers or electron conducting fillers, or a combination thereof. Li-ion conducting fillers may include bismuth telluride (BiTe), antimony telluride (SbTe), lithium-doped tritelluride (LiTea), lithium titanate (“LTO”), lithium lanthanum zirconium oxide (“LLZO”), lithium nitride (Li N), or lithium phosphide (Li ;P), molybdenum oxide (MoO), molybdenum disulfide (M0S2), or anycombination thereof, or similar lithium-ion conducting materials including ceramic materials. Electron conducting fillers may include one or more of carbon, aluminum, or silicon, or other similar electron conducting materials. The enhanced Li-ionic conductivity or electron conductivity of the example Li-Mg composite alloys including lithium-ion conducting fillers or electron conducting fillers may improve lithium utilization by reducing impedance associated with charge transfer during plating.Increasing the Mg content in Li-Mg alloys may also reduce material costs associated with the anode and improve the safety of lithium-based batteries. Additional details related to the performance of lithium-based coin cells including Li-Mg / LTO anodes are described below with reference to Example 3 and FIG. 10.

[0123] Without being bound by any particular theory, the example lithium-ion conducting fillers or electron conducting fillers may disperse in the bulk alloy and reduce the grain size of Li-Mg domains or reduce the diffusion length of Li+ions in the Li-Mg bulk alloy to facilitate faster lithium-ion diffusion across grain boundaries. With faster lithium-ion diffusion, lithium plating / stripping during charge / discharge cycles in lithium- ion batteries may be more uniform and mitigate dendrite growth. Dendrites may penetrate the polymeric or ceramic separators in Li-ion batteries and create a short circuit within a battery resulting in fire hazards.

[0124] Moreover, implementing fillers with density of about 2 g / cm3advantageously conveys substantial decrease on the overall density of the anode as a whole. This results in lesser energy penalties compared to corresponding anodes with fillers having densities greater than 2 g / cm3, particularly where the filler is present in amounts of at least about 20 wt%.

[0125] Further still, using filers characterized by a nano-scale particle size (diameter) can convey similar improvements regarding capacity. For example, in one implementation involving titania filler, 10 wt% of a micro-size LTO filler was not able to activate a Li-Mg (92-8 wt%) anode over 20 cycles, but a corresponding 10 wt% nanosized filler was able to do so. Indeed, increasing the filler concentration to 20 wt% still failed to achieve activation when the filler particles were characterized by a mico- scale size. Thus using nano-scale sized filler material represents an opportunity to achieve lighter mass anode compositions without sacrificing capacity.

[0126] In some implementations, a diffusion coefficient of lithium in Li-Mg / LTO composite alloys may be approximately 2.3 x 10‘8cm2 / s, which is approximately an order of magnitude greater than the diffusion coefficient of lithium in Li-Mg alloys of approximately 3.8 x 10‘9cm2 / s. Magnesium in Li-Mg / LTO alloys primarily controls the reactivity or stability of the alloy, and LTO reduces the size of Li-Mg domains and improves lithium-ion diffusivity. As such, improved lithium-based battery cycle life and discharge capacities and a reduction in the N / P ratio to less than 2 may be possible with Li-Mg alloys including up to approximately 50 wt% Mg and an LTO content of up to approximately 90 wt%. Accordingly, the lithium content in example Li-Mg / LTO composite alloys may be reduced to between approximately 10 wt% and approximately 90 wt%, which in turn reduces material costs associated with the Li-ion battery anode.

[0127] Additionally, the melting point of a Li-Mg / LTO composite alloy is approximately 210 °C, which is greater than the melting point of lithium of approximately 180 °C. Battery safety is enhanced because the thermal runaway onset point in lithium-based batteries increases from approximately 126 °C for a 90 wt% Li - 10 wt% Mg alloy to approximately 236 °C for a Li-Mg / LTO alloy, thereby increasing the temperature at which lithium-based batteries associated with various aspects of the subject matter disclosed herein can be safely used by approximately 110 °C.

[0128] In some implementations, the magnesium content in a freestanding Li-Mg alloy composite anode including a lithium-ion conducting material may be between approximately 5 wt% and approximately 50 wt%. As previously noted, example lithium- ion conducting materials (also referred to herein as lithium-ion conductive fillers) may include bismuth telluride (BiTe), antimony telluride (SbTe), lithium-doped tritelluride (LiTea), lithium titanate (Li^isOn, “LTO”), lithium lanthanum zirconium oxide (LivLaiZnOn. “LLZO”), lithium phosphide (LI T), molybdenum oxide (MoO), molybdenum disulfide (M0S2), or any combination thereof, or any other suitable material described herein or equivalents thereof that would be appreciated by those having ordinary skill in the art upon reading the present disclosure. In some instances, the amount of the lithium-ion conducting material in a freestanding Li-Mg alloy composite anode may be between approximately 1 wt% and approximately 90 wt%. In some other instances, the weight ratio of the Li-Mg alloy to the lithium-ion conducting material maybe between approximately 1 and approximately 9. In some other instances, the weight ratio of the Li-Mg alloy to the lithium-ion conducting material may be approximately 1.5.

[0129] In some implementations, the electron conducting material in a freestanding composite anode may include one or more of carbon, aluminum, or silicon. In some instances, carbon may include graphite.

[0130] In some other implementations, a freestanding anode associated with a lithium-based battery may include a Li-Mg ternary alloy. In some other implementations, a freestanding anode associated with a lithium-based battery may include a Li-Al-Mg ternary alloy. In some instances, an aluminum content in a Li-Al-Mg ternary alloy may be between approximately 5 wt% and approximately 20 wt%. In some instances, a Li-Al- Mg ternary alloy may further include any one of the lithium-ion conducting materials previously described herein. Without being bound by any particular theory, Li- Al intermetallic phases, for example, LLAI or Li<jAL, or similar phases, may be embedded in the Li-Mg alloy microstructure in Li-Al-Mg ternary alloys. These Li- Al intermetallic phases are lithiophilic, and may reduce localized current density profiles, facilitate more uniform lithium deposition (or plating), and improve the rates of lithium-ion diffusion.

[0131] In some implementations, a freestanding anode associated with a lithium- based battery may include a Li-Si-Mg ternary alloy. In some instances, the silicon content in a Li-Si-Mg ternary alloy may be between approximately 5 wt% and approximately 20 wt%. In some instances, the silicon content in a Li-Si-Mg ternary alloy may be approximately 20 wt%. In some instances, a Li-Si-Mg ternary alloy may further include any one of the lithium-ion conducting materials previously described herein.

[0132] In some other implementations, a freestanding composite anode associated with a lithium-based battery may include a Li-Mg / carbon composite anode. In some instances, the carbon content in a Li-Mg / C composite anode may be between approximately 1 wt% and approximately 20 wt%. In some other instances, carbon may include graphite. In some instances, the carbon content in an example Li-Mg / C alloy may be approximately 15 wt%. In some instances, a Li-Mg / C alloy may further include any one of the lithium-ion conducting materials previously described herein.

[0133] In some other implementations, carbon in the example Li-Mg / C alloys may include one or more of carbon nanotubes (“CNT”), carbon nano onions (“CNOs”), carbon nanofibers, or fullerenes. In some instances, carbon may be surface functionalized using CO2 etching and other methods to include surface oxygen containing functional groups. Without being bound by any particular theory, carbon, and in particular graphite, is an electronically conductive additive, and may also function as a current collector, which may dramatically increase the active surface area of the anode and also mitigate dendrite growth. As such, the addition of carbon may increase lithium utilization, discharge capacity, rate capability, and cyclic stability in Li-ion and lithium-based batteries.

[0134] In some implementations, a grain size of Li-Mg domains in any one of the Li- Mg alloys previously described herein may be manipulated via annealing or rapid quenching operations associated with the thermal treatment and mechanical processing of Li-Mg alloys. For example, Li-Mg domain grain growth may be mitigated by annealing Li-Mg alloys at 70% of the melting point of the alloy. In some implementations, annealing Li-Mg alloys associated with lithium-based battery anodes at approximately 150 °C may improve the capacity retention and columbic efficiency of lithium-based batteries. Annealing or rapid quenching may also alter the orientation of body centered cubic (“BCC”) crystalline grain structure in Li-Mg alloys to preferred orientations, for example, the (110) plane or the (200) plane. In some implementations, the grain size of Li-Mg domains in Li-Mg alloys or any one of the Li-Mg composite alloys describe herein after annealing may be less than approximately 175 pm.

[0135] Any one of the freestanding anode implementations previously described herein may also be used in other lithium-ion battery chemistries including, but not limited to, nickel-manganese-cobalt (“NMC”) batteries, lithium iron phosphate (“LFP”) batteries, or nickel cobalt aluminum oxide (“NCA”) batteries.

[0136] In some implementations, any of the freestanding Li-Mg alloy / anodes previously disclosed herein may include an anode protective polymer coating including one or more of polyvinylidene fluoride (“PVDF”), pentaerythritol tetraacrylate (“PETEA”), or polyethylene glycol dimethacrylate (“PEGDMA”), or any combinationthereof, disposed on the freestanding anode. The thickness of the coating layer may be between approximately 10 nm and approximately 10 pm.

[0137] In some implementations, an example lithium-based battery may include any one of the freestanding anodes previously described herein and a fluorinated ether electrolyte. The thickness of the freestanding anode may be up to approximately 100 pm. In some instances, a freestanding anode may include any one of the biphasic alloy anodes including a Li-Mg alloy phase and a Li2Ca alloy phase. In some other instances, a freestanding anode may include any one of the Li-Mg alloy composite anodes including a lithium-ion conducting material or an electron containing material.

[0138] In some implementations, an example fluorinated ether electrolyte may include one or more of lithium nitrate (LiNCL) or lithium bis (trifluoromethanesulfonyl) imide (“LiTFSI”). In some implementations, the concentration of LiTFSI in the fluorinated electrolyte may be between approximately 0.1M and approximately 2M. In some other implementations, the concentration of LiNCh in the fluorinated ether electrolyte may be between approximately 2 wt% and approximately 6 wt%.

[0139] In some implementations, an example fluorinated ether electrolyte may include approximately 50:25:25 (vol%) 1,2-dimethoxyethane (“DME”): 1,3-dioxolane (“DOL”): bis (2,2,2-trifluoroethyl) ether (“BTFE”) and including approximately 0.4 M LiTFSI and approximately 2 wt% LiNCF. In some other implementations, an example fluorinated ether electrolyte may include approximately 50:25:25 (vol%) DME : DOL: 1 , 1 ,2, 2-tctracthoxy ethane (“TEE”) and including approximately 0.4 M LiTFSI and approximately 2 wt% LiNOv

[0140] In some implementations, an example electrolyte may include approximately 50:25:25 (vol%) DME : DOL: 1,1,2, 2-tetrafluoroethyl 2,2,2-trifluoroethyl ether (“TFETFE”) and including approximately 0.4 M LiTFSI and approximately 2 wt% LiNO ;. In some other implementations, an example electrolyte may include approximately 60:20:10:10 (vol%) DME : DOL: TEE: TFETFE and including approximately 0.4 M LiTFSI and approximately 2 wt% LiNOi.

[0141] In some implementations, an example electrolyte may include approximately 50:25:25 (vol%) DME : DOL: l,l,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether(“TTE”) and including approximately 0.4 M LiTFSI and approximately 2 wt% LiNCL. In some other implementations, an example fluorinated ether electrolyte may include LiTFSI at concentrations of between approximately 0.1 M and approximately 1 M, and LINO? concentrations of between approximately 1 wt% and 6 wt%. In some other implementations, an example fluorinated ether electrolyte may include approximately 50:25:25 (vol%) DME : DOL: 1 fluorinated 1,4-dimethoxylbutane (“FDMB”) and including approximately 0.4 M LiTFSI and approximately 2 wt% LiNCL. In some other implementations, the electrolyte may include approximately 1.0 M LiTFSI in approximately 50:50 (vol%) DOL: BTFE.

[0142] Additives including lithium nitrate (LiNO.Q in fluorinated ether electrolyte may dissociate to produce lithium cations (Li+). Alternately, additives including LiTFSI in the electrolyte may dissociate to produce lithium cations (Li+) and TFSE anions. Additives in the electrolyte that may dissociate to lithium ions may also include one or more of lithium lanthanum zirconium oxide (“LLZO”), oxinitrides (e.g., lithium phosphorus oxynitride or “LIPON”), NASICON-type conductors (e.g., lithium aluminum titanium phosphate) or lithium tin phosphorus sulfide (“LSPS”).

[0143] In some example implementations, any one of the previously described freestanding dual phase Li-Mg alloy and Li-x alloy anodes or any of the Li-Mg alloy composite anodes including Li-ion conducting material or electron conducting material or filler may be coated with a surface coating which may react with lithium in the alloy to form a protective layer and further improve the stability of the anode under cycling. In some instances, the anode protective layer may include one or more of polyvinylidene fluoride (“PVDF”), pentaerythritol tetraacrylate (“PETEA”), or polyethylene glycol dimethacrylate (“PEGDMA”), or any combination thereof, disposed on the freestanding anode. In some other instances, a thickness of the anode coating layer may be between approximately 100 nm and approximately 10 pm.

[0144] Without being bound by any particular' theory, PVDF may react with lithium in the freestanding Li-Mg alloy anode to form LIE ions dispersed in a polymeric matrix. The protective layer may improve and / or may be associated with an improvement of lithium ion (Li+) transport from and to the anode during cycling. Reducing lithium- containing dendritic growth from the anode of a Li-S battery may increase the chargerate, the discharge rate, the energy density, the cycle life, or any combination thereof. The polymeric matrix may partially trap TFSI anions produced by the dissociation of additives including LiTFSI in the electrolyte.

[0145] In some implementations, an example lithium-based battery may include a cathode disposed opposite to the anode. As described below with reference to FIGS. 5A- 5E, in some implementations, an example cathode may include one or more porous carbon layers including porous carbon agglomerates of porous carbon primary nanoparticles. In some instances, a respective porous carbon primary nanoparticle may include an inner porous shell disposed about a center of the respective porous carbon primary nanoparticle and enclosing an inner porous carbon region, an outer porous shell enclosing an outer porous carbon region disposed between the inner shell and the outer shell, and an interconnected porous network disposed in and in fluid communication with the inner and outer porous carbon regions.

[0146] In some aspects, the inner carbon region and the outer carbon region of example porous carbon primary nanoparticles may be characterized by an average pore size and an average pore density associated with each region. In some other aspects, the average pore size may decrease along a radial direction from the center to the outer porous shell.

[0147] In some instances, an example porous carbon primary nanoparticle may further include one or more intermediate porous shells disposed between the inner porous shell and the outer porous shell, wherein each of the intermediate porous shells encloses a respective intermediate porous carbon region.

[0148] In some aspects, the porous carbon agglomerates may be characterized by a Raman spectroscopy signature with an ID / IG ratio between approximately 0.95 and approximately 1.05. In some other aspects, the porous carbon agglomerates may be characterized by a Brunauer-Emmett-Teller (“BET”) surface area between approximately 50 m2 / g and 300 m2 / g measured using nitrogen gas. In some aspects, the porous carbon agglomerates may be characterized by an electrical conductivity of between approximately 500 S / m and 20,000 S / m when compressed at a pressure of approximately 12,000 pounds per square inch (psi).

[0149] FIG. 5A shows a schematic diagram 500A of an example porous carhon primary nanoparticlc 505, according to some implementations. In some aspects, the porous primary carbon nanoparticle 505 may resemble carbon nano-onions (“CNOs”). As shown in the example of FIG. 5A, the porous primary carbon nanoparticle 505 may include a core (inner) porous carbon region 511 defined by a first porosity and enclosed within an inner porous shell 513. The inner porous carbon region 511, which may also be referred to herein as the first porosity region, may include a plurality of first pores 501 dispersed therein. An outer porous carbon region 512, which may also be referred to herein as the second porosity region, may be disposed between the inner porous shell 513 and an outer porous shell 510 and may include a plurality of second pores 502 dispersed therein. The inner porous carbon region 511 and the outer porous carbon region 512 may be interconnected by one or more of the first pores 501 or one or more of the second pores 502, thereby interconnecting the first and second porosity regions. That is, the inner porous carbon region 511 may be configured to be in fluid communication with the outer porous carbon region 512 through an interconnected porous network. The inner porous carbon region 511 may be defined by a first pore density, and the outer porous carbon region 512 may be defined by a second pore density that is similar to, or different than, the first pore density.

[0150] Example porous primary carbon nanoparticle 505 may be characterized by an average size or principal dimension (diameter, length, width) of less than approximately 200 nm. In some implementations, an average pore size may gradually decrease along a radial direction from the center 516 of the nanoparticle 505 to the outer boundary 513 of the nanoparticle 505. In some implementations, porous primary carbon nanoparticle 505 may be characterized by a range of pore sizes and pore distributions in each region. The first pores 501 may be configured to retain polysulfides 520, and the second pores 502 may provide pathways or channels for the transport of lithium ions (not shown for simplicity) into and from the porous primary carbon nanoparticles 505 and for pre- loading sulfur 524 into the nanoparticles.

[0151] FIG. 5B shows a transmission electron microscopy (“TEM”) micrograph 500B of aggregates 540 of porous primary nanoparticles 505, according to some implementations. Those skilled in the art will appreciate that the micrographs are shownby way of example only, and that other scales may exist without departing from the scope and spirit of the present implementations. Example carbon aggregates 540 may include an interconnected porous network disposed between adjacent carbon nanoparticles 505. Aggregate 540 may include a plurality of porous carbon primary nanoparticles 505 and, in some instances, may resemble a “string-of-pearls.” In some implementations, the size or principal dimension of aggregate 540 may be between approximately 50 nm and approximately 500 nm.

[0152] FIG. 5C shows a TEM image 500C of agglomerates 545 of porous primary carbon nanoparticles 505, according to some implementations. An agglomerate 545 of porous carbon primary nanoparticles 505 may be characterized by a Brunauer-Emmett- Teller (“BET”) surface area of between approximately 50 m2 / g and approximately 300 m2 / g measured using nitrogen gas. In some implementations, an example agglomerate 545 may be spherical in shape. In some implementations, an agglomerate 545 may be of any shape, including one or more of spherical, spheroidal, dumbbell, cylindrical, elongated cylindrical type, rectangular prism, disk, wire, or irregular.

[0153] FIG. 5D shows a TEM image 500D of surface etched agglomerates 542 of porous primary carbon nanoparticles, according to some implementations. Example agglomerates 545 may be surface etched using methods that include CO2 etching to create pores on the external surface of the agglomerates 545 and to increase the surface area of the carbon agglomerates 545 to yield surface etched agglomerates 542. After etching, the surface etched agglomerates 542 may include three-dimensional graphene carbons (“3DG carbons”) including graphene layers interconnected as three-dimensional (“3D”) graphene structures (not shown for simplicity). The surface etched agglomerates 542 of porous primary carbon nanoparticles may be characterized by a Raman spectroscopy signature with an ID / IG ratio of approximately between 0.95 and 1.05. In some instances, the surface etched agglomerates 542 may be assembled as rigid porous carbon agglomerates by processes including spray drying.

[0154] FIG. 5E shows a schematic diagram 500E of another example porous primary carbon nanoparticle 505, according to some implementations. Example tri-zone porous primary nanoparticle 505 may include a first core (inner) carbon zone or region 551, nested within a second intermediate carbon zone or region 552, which in turn is nestedwithin a third outer carbon zone or region 553. Example first zone 551 may include pores 561 having an average size or principal dimension (diameter, length width) of less than approximately 40 nm, the second zone 552 may include pores 562 having an average size or principal dimension of less than approximately 35 nm, and the third zone 553 may include pores 563 having an average size or principal dimension of less than approximately 30 nm. In some example implementations, pores 561 may be characterized as macropores, the pores 562 in the intermediate region 552 may be characterized as mesopores, and the pores 563 in the outer region 552 as micropores.

[0155] In some implementations, the principal dimension DI of first zone 551 may be less than approximately 100 nm, the principal dimension D2 may be less than approximately 150 nm, and the principal dimension D3 of third zone 553 may be approximately 200 nm. The relative dimensions, porosities, and electrical conductivities of the first zone 551, the second zone 552, and the third zone 553 may be tuned to achieve a desired balance between minimizing the polysulfide shuttle effect and maximizing the specific capacity of a host battery. The first zone (inner core zone) 551 may have a density of carbons of less than approximately 1 g / cc. The third zone (outer zone) 553 bounded by the perimeter or outer shell 555 of particle 205 may have a density of carbons of approximately less than between 1 g / cc and 3.5 g / cc. The second zone (intermediate zone) 552 may have a density of carbons of between approximately 0.5 g / cc and 3 g / cc. Each of the zones 551, 552, and 553 may be characterized by an average pore size and an average pore density associated with each region. The average pore size associated with each of zones 551-553 may decrease along a radial direction from the center of the porous primary carbon nanoparticle 505 to the outer porous shell 555.

[0156] In some implementations, agglomerates of porous primary carbon nanoparticles 505 may be surface etched using methods that include CO2 etching to create pores on the external surface of the agglomerates and to increase the surface area of the carbon agglomerates. After etching, the agglomerates may include three- dimensional graphene carbons (“3DG carbons”) including graphene layers interconnected as three-dimensional (“3D”) graphene structures. The resulting surface etched agglomerates of porous primary carbon nanoparticles 505 may be characterized by a Raman spectroscopy signature with an ID / IG ratio of approximately between 0.95 and1 .05. In some implementations, the resulting agglomerates may be produced by thermal cracking of hydrocarbon feedstock as disclosed in commonly-owncd U.S. Pat. No. 9,862,602, U.S. Pat. No. 10,112,837, U.S. Pat. No. 11,053,121, and / or U.S. Pat. Pub. No. 2021 / 0292170, all of which are incorporated by reference herein in each of their entireties.

[0157] The porous carbon agglomerates as described above may be used to produce carbon-sulfur composites (“CSC”) by sulfurizing the carbon agglomerates. The sulfur to carbon weight ratio may be between approximately 1:5 and 10:1. The sulfur to carbon weight ratio may be approximately 3. A slurry including the carbon-sulfur composites and one or more polymeric binders may be cast as one or more layers or films of carbon material on a suitable substrate to form the cathode in an example Li-S battery. The cathode substrate may include a cathode current collector. The cathode current collector may include aluminum. The carbon agglomerates may resist deformation under high shear mixing, and therefore produce films or layers of carbon of desired porosity, thickness, and packing density. In some implementations, the cathode may be characterized by a packing density of carbon material on the substrate (including sulfur, binder, and other constituents) of at least approximately 7 mg / cm2, which in turn increases the sulfur loading at the cathode and may reduce the N / P ratio in a Li-S battery.

[0158] In some implementations, the porous carbon agglomerates as disclosed herein may resist deformation under high shear mixing, and therefore produce films or layers of carbon of desired porosity, thickness, and packing density. In some implementations, the porous carbon agglomerates may resist deformation at shear rates of at least 500 s’1during mixing of a slurry including the porous carbon agglomerates in a high shear mixer. The slurry may be disposed as one or more porous carbon layers on the cathode substrate (also referred to herein as the cathode current collector).

[0159] In some implementations, as described below with reference to FIGS. 6A-6C, an example cathode for a lithium-based battery may include porous carbon agglomerates of porous carbon primary nanoparticles, which include one or more interconnected bundles of electrically conductive graphene layers. In some aspects, the graphene layers may be arranged as one or more stacks connected to each other and defining a 3D porous scaffold structure including mesopores. In some other aspects, the one or more stacksmay be disposed substantially orthogonal to each other. In some instances, the graphene layers may be characterized by a linear dimension of between approximately 50 nm and 200 nm. In some other instances, the graphene layers may include one or more of single layer graphene (“SLG”), few layer graphene (“FLG”), or many layer graphene (“MLG”).

[0160] FIG. 6A shows a schematic diagram of a mesoporous carbon nanoparticle 600A having an interconnected bundle of electrically conductive graphene layers arranged to form a 3D open porous scaffold structure, according to some implementations. Nanoparticle 600A and porous carbon agglomerates including nanoparticles 600A may be produced using a high throughput, low-cost, cracking of a hydrocarbon gas such as natural gas, in an atmospheric microwave plasma reactor. An example microwave plasma reactor is disclosed in commonly-owned U.S. Pat. No. 9,767,992, which is incorporated by reference herein in its entirety. For example, the agglomerates may be formed in-flight and grown by adding additional carbon-based materials derived from incoming carbon-containing gas within a microwave-plasma reaction chamber.

[0161] The carbon nanoparticles 600A may include three-dimensional (“3D”) multimodal mesoporous carbon nanoparticles. A mesoporous material, as generally understood and as referred to herein, includes a material containing pores with diameters between 2 nm and 50 nm, according to IUPAC nomenclature. For the purposes of comparison, IUPAC defines microporous material as a material having pores smaller than 2 nm in diameter and defines macroporous material as a material having pores larger than 50 nm in diameter. In some instances, mesoporous carbon particle 600A may be characterized by a three-dimensional (“3D”) hierarchical porous structure including pores 680 (whitespace between carbon nanoparticles 600A). In some aspects, at least a portion of the hierarchical porous structure may further define a 3D open porous scaffold structure 681.

[0162] The nanoparticle 600A may include one or more interconnected bundles 682 of electrically conductive graphene layers or sheets. Each interconnected bundle 682 may include one or more stacks 683 of graphene layers. Each stack 683 may include a plurality of graphene layers 686 that are generally stacked horizontally as more clearly shown in stack 684. One or more stacks 683 of graphene layers 686 may be arranged toform a 3D porous scaffold structure 681 including mesopores. That is, a plurality of stacks 683 of electrically conductive graphene layers 686 may be sintered together to define the 3D open porous scaffold structure 681 (which includes mesopores 680 in the example of FIG. 6A). In some implementations, one or more of the stacks 683 may be connected substantially orthogonal to each other. The open porous scaffold structure 681 may be configured to provide electrical conduction between contact points (not shown for simplicity) of the stacks of graphene layers 686. In some implementations, each graphene layer 686 may be characterized by a diameter or linear dimension (“La”) of between approximately 50 nm to approximately 200 nm. In some implementations, the graphene stack 683 may include few layer graphene (“FLG”), which may be composed of 5 to 15 layers of graphene.

[0163] A plurality of porous carbon primary nanoparticles 600A may be coalesced or joined to form porous carbon agglomerates of porous carbon primary nanoparticles. In this disclosure, three-dimensional graphene carbons (“3DG carbons”) include porous carbon agglomerates of mesoporous nanoparticles 600A. In some implementations, the example 3DG carbons described herein may be characterized by a Brunauer-Emmett- Teller (“BET”) surface area measured using nitrogen gas of approximately 50 to 300 m2 / g. In some implementations, the 3DG carbons may be characterized by a graphene to amorphous carbon ratio of between approximately 1% and 95%. In some implementations, the 3DG carbons may be characterized by a carbon purity of at least 99.9%. The 3DG carbons may be characterized by an electrical conductivity of between approximately 500 S / m and approximately 20,000 S / m when compressed at pressure of approximately 12,000 pounds per square inch (“psi”). The open porous scaffold structure 681, while confining sulfur, may also provide a host scaffold-type structure to manage volume expansion due to the formation of long chain polysulfides.

[0164] In some implementations, sulfur may be confined in the pores 680 of open porous scaffold structure 681. In some implementations, sulfur may also be confined in the scaffold structure spaces 685 formed by orthogonally joined stacks 683 of graphene layers 684.

[0165] In some implementations, the porous carbon primary nanoparticles 600A may include a plurality of interconnected crinkled 3D graphene sheets, a plurality of non-hollow carbon spherical particles (“NHCS”), flat graphene, wrinkled graphene, or a plurality of carbon nano-onions (“CNOs”). In some implementations, the porous carbon primary nanoparticles 600A may include wavy or flexible graphene layers that resemble crinkled paper and may be produced using microwave processes. The graphene layers may be flexible as they may be fused with each other at sp3type defects in a sp2graphene lattice structure.

[0166] FIG. 6B shows a SEM micrograph 600B of porous carbon agglomerates 402, according to other implementations. In some instances, plasma-based processing conditions applied or performed in a reactor such as a microwave reactor may be adjusted with a high degree of tunability to achieve of porous carbon agglomerates and graphene- on-graphene densification to yield the complex 3D carbons 602. The porous carbon agglomerates 602 may be surface etched using methods such as CO2 etching to create pores on the external surface of the aggregates and to increase the surface area of the aggregates.

[0167] The porous carbon agglomerates described herein and characterized using Raman spectroscopy show a high degree of order and uniformity of structure. In this disclosure, “graphene” refers to an allotrope of carbon in the form of a two-dimensional, atomic-scale, hexagonal lattice in which one atom forms each vertex. The carbon atoms in graphene may be sp2hybridized carbon atoms. Additionally, graphene has a Raman spectrum with two main peaks: a G-mode at approximately 1580 cm'1and a D mode at approximately 1350 cm'1(when using a 532 nm excitation laser). The porous carbon agglomerates may be characterized by a Raman spectroscopy signature having an ID / IG ratio between approximately 0.95 and approximately 1.05.

[0168] FIG. 6C shows a TEM micrograph 600C of porous carbon agglomerates, according to some implementations. As shown, the 3D few-layer graphene (“FLG”) structure 604 may be considered to be a porous carbon aggregate at a 50 nm scale. Those skilled in the ail will appreciate that the micrographs are shown by way of example only, and that other scales may exist without departing from the scope and spirit of the present implementations.

[0169] Any one of the Li-S battery cathode or anode implementations previously described herein may be configured or disposed for use in cylindrical batteries, prismaticbatteries, pouch cells, or any other suitable geometrical shape. A Li-S cylindrical battery may comport with the dimensions of an 18650 battery (approximately 18 mm diameter x approximately 65 mm length), a 21700 (approximately 21 mm diameter x approximately 70 mm length) battery or a 4680 (approximately 46 mm diameter x approximately 80 mm length) battery. In some implementations, a Li-S battery may have a prismatic form factor that can comport with the dimensions of a CP3553 battery. For example, an example Li-S battery may have a height between approximately 56 mm and approximately 58 mm, a length between approximately 34 mm and approximately 36 mm, and a width between approximately 6 mm and approximately 8 mm.

[0170] FIG. 7 shows a schematic diagram 700 depicting an example cylindrical battery 700, according to some implementations. Battery 700 may include a shell 710 and a jelly roll 720. Shell 710 may have a longitude axis indicated as AA’ in FIG. 4, and jelly roll 720 may be disposed along the longitudinal axis AA’ within shell 710. Jelly roll 720 may have a cross section in a circle, a rectangle, a square, a triangle, or any other geometric shapes. Jelly roll 720 may include an anode 722, a first barrier layer (or separator layer) 724, a cathode 726, and a second barrier layer 728, each in the form of a rollable sheet. Anode 722, first barrier layer 724, cathode 726, and the second barrier layer 728 may be laminated on top of one another. As such, anode 722 and cathode 726 may be separated by the first and the second barrier layers to avoid undesirable short circuiting within battery 700. In some other implementations, a center pin or mandrel (not shown in FIG. 7 for simplicity) may be attached to an inner edge of anode 722, and the lamination of cathode-first barrier layer-anode-second barrier layer may be radially wound or rolled around the center pin to form the jelly roll 720. Anode current collector 702 (in the event the anode is not a free-standing anode) and cathode current collectors 704 may be integrated into the anode and cathode layers, respectively.

[0171] In some implementations, anode 722, first barrier layer 724, cathode 726, and second barrier layer 728 may share the same dimensions, and the sheets may be aligned with one another during the rolling process so that there are no sheets protruding from the jelly roll 720. Either anode 722 or cathode 726 current collectors may include a current collector tab, which may protrude out after the sheets are wounded into the jelly roll 720. Tab 723 may connect the anode 722 or the cathode 726 to a negative or positive terminal(not shown in FIG. 7 for simplicity), respectively, via any suitable process including a mechanical welding process. In some implementations, tab 723 may be the cathode current collector tab. The anode current collector (not shown for simplicity) may be disposed at the outer edge of the jelly roll 720, and the cathode current collector tab 723 may be disposed approximately in the center of the jelly roll 720.

[0172] In some implementations, either electrode (e.g., the anode 722 or the cathode 726) may be arranged in a misalignment with the other electrode and the first and the second barrier layers 724 and 728 during the rolling process so that a portion 725 may protrude out of the jelly roll 720. In some aspects, an electron conductive glue (not shown in FIG. 7 for simplicity) may be disposed within shell 710 at the top and bottom of shell 710. The protruding portion 725 may be connected to the negative or positive terminal of shell 710 via electron conductive glue, and thereby eliminates the need for a mechanical welding process. In some implementations anode 722, anode current collector (not shown), first barrier layer 724, cathode 726, cathode current collector 704 and the second barrier layer 728 may be laminated on top of one another. A center pin or mandrel (not shown in FIG. 7 for simplicity) may be configured as the cathode terminal and may be attached to the cathode current collector 704. When disposed as a jelly roll, the anode current collector may be disposed at the outer edge of the jelly roll 720, and the cathode current collector 404 may be disposed approximately in the center of the jelly roll 720.

[0173] In various implementations, anode 722 may be any suitable material that is typically used as an anode in a Li-S battery. For example, anode 722 may be a lithium foil or a lithium substrate. In some instances, anode 722 may include a current collector to support the lithium foil or the lithium substrate. In some aspects, the anode 722 may include any one of the free-standing Li-alloy anodes, including Li-Mg composite anodes and previously described herein.

[0174] In some implementations, cathode 726 may include one or more layers of films or CSC including any of the previously described rigid porous carbon agglomerates including metal nanoparticles. Cathode 726 may be disposed on cathode current collector 704. The cathode films may coat both sides of a current collector, such as an aluminum foil, to provide the maximum cathode capacity. The cathode CSC including any of the previously described rigid porous carbon agglomerates having metal nanoparticles mayinclude multiple pores to micro-confine sulfur as the cathode electroactive material. The clcctroactivc material (sulfur) may constitute approximately between 60 wt% and 90 wt% of the cathode films. The electroactive material of the cathode 726 may include other suitable sulfur-containing materials, such as lithium sulfide.

[0175] Battery 700 may have electrolyte (not shown in FIG. 7 for simplicity) incorporated into the jelly roll 720. In some implementations, battery 700 may have a liquid electrolyte that may be added to shell 710 after jelly roll 720 is disposed in shell or casing 710. In some other implementations, battery 700 may include a non-aqueous electrolyte such as solid-state electrolyte, gel electrolyte, or polymer film electrolyte incorporated into jelly roll 720. For example, between the first and the second barrier layers 724 and 728, one barrier layer may function as a separator and the other one may function as a non-aqueous electrolyte film. In some other implementations, each of the first and second barrier layers 724 and 728 may function as both a separator and a nonaqueous electrolyte film. The electrolyte may include any one of the electrolyte compositions previously described herein.

[0176] In some implementations, a microporous monolayer polypropylene membrane may be used as a separator disposed between the anode 722 and the cathode 726. The porosity of an example separator (e.g., CelgardR2500) may be approximately 55%. The separator may have a similar ionic conductivity as the electrolyte but may serve to reduce lithium dendrite formation. The separator may be formed from a ceramic containing material that does not chemically react with metallic lithium. As a result, the separator with ceramic containing material may be used to control lithium-ion transport through the pores dispersed across the separator, while concurrently preventing a short-circuit by impeding the flow or passage of electrons through the electrolyte. The separator layer may include a mechanical strength enhancer coated and / or deposited on the anode. The mechanical strength enhancer may provide structural support for the battery, may prevent lithium dendrite formation from the anode, and / or may prevent protrusion of lithium dendrite throughout the battery. In some exemplary implementations, ceramic particles may be impregnated in the microporous monolayer polypropylene membrane. In some exemplary implementations, the separator may include a ceramic coated separator.

[0177] In a cylindrical Li-ion battery, the dense packing of the various layers in the jelly roll 720 and volume changes during discharge-charge cycling may cause mechanical stresses and ageing of the battery 700. As previously described, volume changes may result from non-uniform lithium plating and dendrite formation at the anode, polysulfide “shuttle effect” and growth of solid electrolyte interfaces. Dendrites may even cause fires due to localized heating. Also, pit formation on the anode 722 leads to non-homogenous transport of Li ions from the anode 722 to the cathode 726 and also to fracture of the protective coating / layers disposed on the anode. Similarly, during the charging cycle, lithium dendrites may be formed on the metal anodes due to non-homogenous transport and deposition of Li ions from the cathode to the anode. Pitting and / or dendrite formation leads to uneven stresses and volumetric expansion of the jelly roll 720, which over time causes the layers of the roll 720 to lose intimate contact with one another to exacerbate these issues and lead to accelerated degradation / capacity fade. Cathodes including any one of the previously described CSC materials including any of the previously described porous carbon agglomerates, Freestanding anodes including any one of the Li-Mg alloy compositions, and any one of the previously described electrolyte compositions may mitigate the polysulfide shuttle effect and the effect of mechanical stresses and increase the cycle life of Li-S batteries.

[0178] As noted hereinabove, according to various embodiments the presently described inventive concepts include the use of Li-Mg alloys and Li-Mg-X alloys containing a ternary component as an active anode material. Due to a wide range of possible compositions, the solid solution phase of these Li-Mg alloy-based anodes can provide high specific energy of 500 Wh / kg, with a Mg content up to about 50 wt% (or about 18 at%), according to various embodiments.

[0179] Indeed, Li-Mg alloy anodes have shown significant (e.g., >2X) improvement in the lifespan of the inventive Li / S cells, due to their inherent chemical and electrochemical stability during cycling in our battery electrolytes. They were shown to function well with less electrolyte content (electrolyte to sulfur ratio) and reduced anode reserve (low anode to cathode capacity ratio), both contributing to higher specific energy. The use of Li-Mg alloy also enabled substrate-free (particularly copper-free) anode design, which resulted in further increase (i.c., about 10%) in specific energy. While certain implementations ofthe inventive concepts may include lesser amounts of Mg (e.g., about 10 wt% or less), analysis shows that higher Mg contents can be used without sacrificing the high specific energy benefits, up to about 50 wt% (or about 18 at%) of Mg in Li-Mg alloys.

[0180] Without wishing to be bound to any particular theory, the inventors have observed that inclusion of magnesium and / or ternary components as described herein advantageously reduces the grain size (and, consequently, increases the number and dispersion of grain boundaries) of the resulting alloy. As grain boundaries serve as ionically conductive pathways, and particularly as a lithium diffusion highway, the inventive alloys presented herein are able to perform as well as or better than conventional lithium-based anodes.

[0181] Even with a higher Mg content, improved anode stability and cycle life are attainable. In addition, with increasing amounts of magnesium, and / or ternary components such as aluminum, silicon, graphene, calcium (Ca), gallium (Ga), boron (B), tin (Sn), aluminum (Al), indium (In), bismuth (Bi), antimony (Sb), tellurium (Te), carbon (C), silicon (Si), bismuth telluride (BiTe), antimony telluride (SbTe), zinc (Zn), combinations thereof, etc. as described herein, the resulting anode composition advantageously has improved mechanical strength, even when total mass of the anode is held constant across the various biphasic alloys and alloys containing ternary components. In various implementations, the amount of the ternary component in the composition may be anywhere in a range from about 1 wt% to about 90 wt%, or any value therebetween or subrange therein.

[0182] Further still, increasing the amount of secondary and / or ternary components in the alloy can substantially reduce overall cost and simplify supply chain logistics compared to anode compositions of pure lithium or relatively higher lithium content.

[0183] Reducing the amount of lithium present in the electrochemical cell can also reduce the amount of undesired (e.g., parasitic) reactions and amount of lithium used during normal cycling. The result, as shown in the data presented herein, is improved cycle life, improved stability (both during cycling and in long term storage).

[0184] However, it is worth noting that during development of the presently described inventive concepts, the inventors encountered serious kinetic issues in several embodiments including high Mg content, i.e., greater than about 5 wt%. With Mg contentabove 5 wt%, the inventors observed low cell capacities for the first few cycles, suggesting some form of activation required for the anode to deliver the expected high capacities.

[0185] Activation lasted from about 2-20 cycles, depending on the amount of Mg in the anode. The higher the Mg content, larger is the activation, which we believe is a result slow diffusion of Li through the Mg-rich solid solution (see Fig. 2 and corresponding descriptions below). This is indeed a disadvantage, because the alloys containing more Mg are expected to be electrochemically stable and show improved cycle life. High-Mg alloys are also expected to be mechanically stable, with less volumetric change than Li metal experiences during cycling.

[0186] Another advantage with the use of a Li alloy, especially a low-cost Li alloy in lieu of pure Li metal pertains to the cost and availability of Li metal for large-scale production of Li-based cells. Lithium metal has been identified as a critical resource material for Li metal batteries. Even though the concerns of its availability have been partially relieved with recent discovery of new Li resources, production of sufficient elemental Li of sufficient quality to be used in batteries remains a significant challenge, and major contributor to overall cost of electrochemical cells implementing lithium-based anodes.

[0187] Mechanistically, the processes contributing to the slow activation of the Li-Mg alloy with more than about 10 wt% Mg are evident during the stripping of lithium in the first discharge in a Li-Mg / Li-Mg symmetric cell. After about 5 mAh / cm2of Li is stripped from the alloy, there is an upswing in the anode potential by about 300-500 mV, indicative of transition to a secondary, Mg-rich phase (with higher redox potential).

[0188] This voltage transition occurs even at low rate in the first discharge and may be attributed to slow diffusion of Li within the alloy. Interestingly, this potential transition vanishes from the second cycle onwards, implying that the alloy has been activated.

[0189] To address the above issue poor Li diffusion, the presently disclosed inventive concepts include the use of a ternary component in the anode, preferably either a metallic component that forms an alloy with Li in a separate phase, or a ceramic component. However, other components such as carbon-based, silicon-based, etc. may be utilized as ternary components without departing from the scope of the inventive concepts disclosed herein.

[0190] Unlike pure Li-Mg alloys, with the addition of ternary component(s), the alloy becomes biphasic. Accordingly, compositions including alloyed Li and Mg, and at least one ternary component, are referred to herein as “biphasic alloys” or “Li-Mg-X” alloys, interchangeably. It should also be noted that, according to preferred embodiments, the inventive biphasic alloys as described herein are characterized by a monolithic, three- dimensional structure. However, those having ordinary skill in the art will appreciate that the structure in particular of the inventive biphasic alloys described herein may be arranged in any suitable configuration or manner that would be appreciated by those having ordinary skill in the art upon reading the present disclosure. For instance, the structure may be porous, may have a substantially lattice- or web-like configuration, may comprise multiple monoliths arranged according to a predetermined two dimensional or three dimensional pattern, may be hollow, etc. as would be appreciated by skilled artisans upon reading the instant descriptions.

[0191] The ternary compound is preferably well dispersed in the anodes and separates the Li-Mg alloy into well distributed smaller particles with shorter diffusion length compared to pure Li-Mg alloy. With the slow diffusion of Li thus overcome, the inventive biphasic alloys do not suffer from the activation issues discussed hereinabove regarding Li metalbased and conventional Li alloy-based materials. High Mg contents up to 50 w% (or about 18 at%) can be utilized in the Li-Mg alloy in the presence of these ternary additions, yielding batteries with improved performance relative to pure Li-Mg alloys and other conventional Li-alloy compositions.

[0192] Some of the salient aspects of these biphasic Li-Mg-X alloys are described below.

[0193] Li and Mg share a diagonal relationship in the periodic table and have comparable atomic radii, leading to extended solid solubility — a single BCC phase solid solution exists over 11.5-100 wt% Li in Li-Mg.

[0194] The biphasic Li-Mg-X alloy is truly a 3D anode structure. The secondary phase can act as a scaffold-like structure, even under deep delithiation, while both maintaining the mechanical integrity of the anode and facilitating insertion and removal of Li+ions during charge / discharge cycling.

[0195] Volumetric changes may be reduced to -10-15% during cycling, which will have benefits including minimizing morphology-associated failures.

[0196] Moreover, a matrix of Li-poor Li-Mg alloy with high electric and ionic conductivity can be formed after Li stripping, which can act as an excellent current collector and host for subsequent Li plating. Most importantly, the microstructural and bulk integrity can be retained during cycling due to the conducting matrix.

[0197] Ternary additives improve the effective diffusion coefficient of lithium within the alloy and can support high discharge (delithiation rates). Likewise, the SEI of the biphasic anode will have favorable plating kinetics due to ionophilicity of the ternary addition to the Li-Mg alloy (particularly where the ternary component is or includes Si).

[0198] Because of the enhanced stability of solid electrolyte interphase with these ternary additions, the cycle life is improved.

[0199] Overall, perhaps the most significant benefit of these biphasic Li-Mg-X alloys is the reduction of the Li content without any loss in performance. Replacing Li in Li-Mg-X with more abundant and inexpensive materials (higher Mg, Si, C and LTO), once again without any loss in performance (i.e., in these alloys Li is being used more efficiently) is significant, as lithium is deemed as a critical material both in cost and supply. This will have significant benefits not only Li-S cells but all Li metal cells.

[0200] Adding graphite platelets also provides improved pathways for lithium ion transport. Morphology (plate like structure) is also an important optimization factor to facilitate intercalation of the graphene into the lithium bulk. Crystallographic orientation also appears important and may be determined based on composition and processing condition.

[0201] This also improves the diffusion of lithium during stripping, and diffusion of lithium ions between the electrodes in the battery as a whole.

[0202] According to Sand’s time equation1, Li dendrite growth can be controlled by increasing the effective surface area of the lithium-based anode.> zeFc^DLi+ 1 T Equation 1 ) 2 W where: j is current density, T is transition time (defined as the period when the Li+ concentration in the electrolyte approaches zero at the electrode surface), zeis electron number per unit, F is Faraday’s constant, c is salt concentration, and DLi+ is the diffusion constant.

[0203] Accordingly, the presently described inventive concepts include novel anode compositions for use in lithium-based electrochemical cells, more particularly to a three dimensional (3D) composite anode including materials that are both electronically conductive and conductive to Li+ions.

[0204] One class of suitable materials include carbon based additives such as nongraphitizing carbon (also referred to as “hard carbon”) and carbon nanofibers. While these materials satisfy the conductivity requirements of the presently disclosed inventive concepts, forming alloys with lithium proves difficult because the carbon based additives cannot be easily infused into lithium (particularly molten lithium).

[0205] Accordingly, the inventive concepts described herein also include lithiating graphitic carbons and introducing graphite as an electrochemically inert phase to ease diffusion and mitigate or prevent formation of dendrites in the resulting Li-C alloyed anode material.

[0206] Using pure lithium metal as the active anode material proves unfeasible due to morphological (especially volumetric) changes at moderate to high current densities, as well as high chemical reactivity. However, the probability of dendritic growth in the case of lithiated graphite is lower than pure Li-metal and common Li-alloys at moderate current densities.1Stolz, et al. “The Sand equation and its enormous practical relevance for solid-state lithium metal batteries’", Mater. Today 44:9-14 (2020).

[0207] Moreover, it is preferable to have high surface area porous electrodes which can sustain smoother plating & stripping morphologies.

[0208] In accordance with the presently described inventive concepts, graphite intercalates with lithium and forms an electrochemically inert phase, which does not take part in charge or discharge reactions, but rather acts as a scaffold to facilitate uniform nucleation on the anode surface, preventing accumulation of lithium deposits on said surface and thus mitigating or preventing dendritic growth within the electrochemical cell. These advantages may be extended with use of a Li-Mg alloy anode active material.

[0209] In addition, intercalation of carbon, particularly graphitic carbon, into lithium advantageously provides ionically conductive pathways and allows graphitic carbon to serve as an active material and / or a lithium rcscrvior.

[0210] Accordingly, in preferred embodiments, the composite anode material comprises a Li-Mg alloy. In particularly preferred embodiments, the composite anode material comprises an alloyed combination of Li, Mg, and C. The composition may comprise Li- Mg alloy components, Li-C components, and combinations thereof, according to various embodiments.

[0211] During the first stripping cycle in a Li-Mg alloy anode, there is a diffusion limitation, which makes some portions of lithium inaccessible. Again, according to the presently described inventive concepts, graphite acts as an electron conductor, and when included in the Li-Mg alloy anode, facilitates diffusion of lithium

[0212] Without wishing to be bound to any particular theory, the inventors propose that the interfaces between carbon particles and lithium in the composite anode composition provide additional ionic pathways for conduction of Li+, thus improving diffusion in the bulk and at the surface of the anode.EXAMPLES

[0213] In the examples described below, the electrolyte used in the Li-S battery implementations include approximately 50:25:25 (vol%) DME: DOL: BTFE and including approximately 0.4 M LiTFSI and approximately 2 wt% Li NO ;. For symmetric half-cell Li-S battery tests, the example electrolyte may include approximately IM lithium polysulfides, Li2Se.EXAMPLE 1 . Cathode discharge capacity of lithium-hased coin cells including a freestanding biphasic alloy anode including Li-Mg alloy and a LiaCa alloy at C / 3 discharge rate.

[0214] FIG. 8A shows a plot 800A illustrating cathode discharge capacity of lithium- based coin cells including freestanding biphasic anodes including a Li-Mg alloy phase and a LECa alloy phase, according to some implementations. Cathode discharge capacity at C / 3 rate of example lithium-based coin cells was compared to cells including 72Li- 28Mg alloy (72 wt% lithium, 28 wt% magnesium) anode. Four biphasic alloys including Li-Mg-Ca contents (wt%) of (a) 61% Li, 21% Mg, 18% Ca, (b) 55% Li, 17% Mg, 28% Ca, (c) 67% Li, 25% Mg, 8% Ca, and (d) 70% Li, 26% Mg and 4% Ca were evaluated as freestanding anode alloy candidates. The weight ratio of Li-Mg alloy to the LFCa alloy was between approximately 0.1 and approximately 20. The anode thickness in each case was approximately 100 pm. Formation cycles included 2 discharge / charge cycles at C / 20 rate and 1 cycle at C / 10 rate. The cathode loading was approximately 7.5 mg / cnr. The cathode capacity in each case was approximately 4 mAh / cm2. A Celgard PP2075 separator was used between the cathode and anode. The anode did not include any polymeric material coating. The E / S ratio was approximately 5.

[0215] Referring to FIG. 8 A, the cells with biphasic alloy anodes including 61% Li, 21% Mg, 18% Ca, and 55% Li, 17% Mg, 28% Ca provided a discharge capacity of at least 400 mAh / g at approximately 150 cycles when compared to the 72Li-28Mg alloy, which required approximately 100 formation cycles to reach a discharge capacity of approximately 400 mAh / g.

[0216] To examine the effect of calcium content on discharge capacity, alloys were prepared with calcium content varying from 2 at% (atomic %) to 10 at % in the dualphase alloy including Li-Mg alloy and Li2Ca alloy. FIG. 8B shows another plot 800B illustrating cathode discharge capacity of lithium-based coin cells including biphasic freestanding anodes including a Li-Mg alloy phase and a Li2Ca alloy phase, according to some implementations. As can be seen, calcium content of at least 5 at% is required to realize a discharge capacity of approximately 600 mAh / g. Without being bound by any particular theory, it appears that increasing the calcium content in the example biphasicalloy anodes results in a significant boost in discharge capacity even with Mg-rich Li-Mg alloy in the biphasic alloy.EXAMPLE 2. Rate capability tests of lithium-based symmetric cells including a including a freestanding composite anode including a Li-Mg alloy and LTO.

[0217] FIG. 9A shows a plot 900A illustrating the rate capability test performance of lithium symmetric cells including a freestanding composite anode including a Li-Mg alloy and LTO, according to some implementations. The rate capability test in the symmetric cells were conducted at areal current densities from 0.4 mA / cm2to 13 mA / cm2. In the symmetric cells, Li-Mg or Li-Mg / LTO electrodes were separated by a Celgard PP2075 separator. Rate capability tests may be used to monitor voltage loss at increasing current densities. Negligible voltage loss or polarization suggests that the cell is capable of high discharge capacities. As can be seen from FIG. 9A, the cells with Li- Mg / LTO composite anodes show negligible voltage loss across current densities from 0.4 mA / cm2to 13 mA / cm2compared to cells with Li-Mg alloy anodes. At a current density of 13 mA / cm2, the symmetric cells the Li-Mg / LTO composite anodes showed a voltage loss of only approximately 0.12 V, which is approximately a third of the overpotential of approximately 0.3V measured using the symmetric cells using Li-Mg anodes.

[0218] FIG. 9B shows a plot 900B illustrating corrosion current after lithium stripping measured using lithium symmetric cells including a freestanding composite anode including a Li-Mg alloy and LTO, according to some implementations. FIG. 9C shows a plot 900C illustrating corrosion current after lithium plating measured using lithium symmetric cells including a freestanding composite anode including a Li-Mg alloy and LTO, according to some implementations. The corrosion currents after stripping and plating were obtained using Tafel plots (not shown). Referring to FIG. 9B, the corrosion current after stripping in cells with Li-Mg anodes and Li-Mg / LTO composite anode is not significantly different. Additionally, the significantly higher corrosion current associated with cells including lithium-mctal anodes indicate that cells with Li-Mg anodes may result in better cyclic stability compared to cells with lithium- metal anodes.

[0219] Referring to FIG. 9C, the corrosion current after lithium plating suggests that the low reactivity of the Li-Mg / LTO composite anode may be a promising candidate forincreasing the cyclic stability in lithium-based batteries. As previously discussed with reference to FIG. 9A, the cells with Li-Mg / LTO composite anodes also showed negligible voltage loss across current densities from 0.4 mA / cm2to 13 mA / cm2indicative of high discharge capacities.EXAMPLE 3. Cathode discharge capacity of lithium-based coin cells including a freestanding Li-Mg / LTO composite anode at C / 3 discharge rate.

[0220] FIG. 10A shows a plot 1000A illustrating cathode discharge capacity of lithium-based coin cells including a freestanding Li-Mg / LTO composite anode including a Li-Mg alloy and LTO, according to some implementations.

[0221] Cathode discharge capacity at C / 3 rate of example lithium-based coin cells with Li-Mg / LTO composite anodes was compared with cells including 72Li-28Mg alloy anode (72 wt% lithium, 28 wt% magnesium) and cells with 90Li-10Mg alloy (90 wt% lithium, 10 wt% magnesium) alloy anode. Two Li-Mg / LTO composite anode compositions were evaluated: 72Li-28Mg / LTO and 90Li-10Mg / LTO. The anode thickness in each case was approximately 100 pm. Formation cycles included 2 discharge / charge cycles at C / 20 rate and 1 cycle at C / 10 rate. The cathode loading was approximately 7.5 mg / cm2. The cathode capacity in each case was approximately 4 mAh / cm2. A Celgard PP2075 separator was used between the cathode and anode. The anode did not include any polymeric material coating. The E / S ratio was approximately 5. The anode did not include any polymeric material coating.

[0222] Referring to FIG. 10A, the cells with 72Li-28Mg / LTO composite anodes were characterized by higher reactivity and improved cycling through approximately 200 cycles compared to the performance of the 72Li-28Mg alloy anode. The cells with 72Li- 28Mg / LTO composite anodes also had better cyclic stability than the cells with the 90Li- lOMg / LTO anodes indicating that the addition of LTO resulted in improving cyclic stability at high discharge capacities of approximately 600 mAh / g and confirm the observations associated with FIGS. 9A-9C. Optimizing the Li-Mg composition (for example, increasing Mg content) and screening of lithium-ion conductive fillers may further improve the cyclic stability of lithium-based batteries without sacrificing discharge capacity.

[0223] With continuing reference to Li-Mg / LTO alloys, FIG. 10B shows plots 1000B, 1000C, and WOOD, which respectively depict discharge capacity, capacity retention, and Coulombic Efficiency of an exemplary Li-Mg / LTO alloy containing about 43 wt% lithium, about 17 wt% magnesium, and 40 wt% LTO, relative to baseline Li-Mg. As stated previously, including LTO in the alloy composition extends cycle life, but also improves discharge capacity, capacity retention, and Coulombic Efficiency of the corresponding electrochemical cell.

[0224] As shown in FIG. 10C via plots 1000E and WOOF, when using LTO as a ternary component, both specific capacity and Coulombic efficiency of an inventive biphasic alloy increase with increasing amount of magnesium, even after over 200 cycles.

[0225] According to various embodiments, the LTO component of Li-Mg-LTO biphasic alloys may include any suitable amount of Li, Ti, and O, and may have any appropriate crystalline structure that is known in the art to be a composition falling under the general category of “lithium titanium oxide” or “lithium titanates”, including but not limited to lithium titanate, lithium titanate spinel, lithium metatitanate, lithium orthotitanate, Ramsdellite lithium titanate, etc. as would be understood by a person having ordinary skill in the art upon reading the present disclosure. Generally speaking, the LTO component may have a chemical formula of LixTiyOz, where x is a value in a range from about 1 to about 17, y is a value in a range from about 1 to about 28, and z is a value in a range from about 2 to about 56. According to several illustrative embodiments, the LTO component may have a chemical formula of LUTisO^, LiyTisOn, Li TiO , Li4TiO4, etc. as would be understood by a person having ordinary skill in the art upon reading the present disclosure. Additional exemplary chemical formulations that are to be considered within the scope of “LTO” as referenced herein are provided in Table 1, below.Table 1 - Exemplary LTO formulations

[0226] Furthermore, in various implementations, the LTO component of Li-Mg-LTO alloys may be doped with one or more dopants selected from K+, Ag+, Sn2+, Mg2+, Ca2+, Zn2+, AI3+, Ni2+, Ga3+, Cr3+, Co3+, La3+, Y3+, Zr4+, Ru4+, Mo4+, Mn4+, V5+, Ta5+, Nb5+, Sr2+, or any combination thereof. Moreover, the one or more dopants may be present in any suitable amount as would be understood by one having ordinary skill in the art upon reading the present disclosure. For instance, in select implementations, the dopant(s) may be present in any amount ranging from about 0.01 at% to about 3.0 at%, such as about 0.01 at%, about 0.023 at%, about 0.04 at%, about 0.23 at%, about 0.47 at%, about 0.95 at%, about 1.19 at%, about 1.42 at%, about 2.38 at%, about 2.85 at%, about 3.0 at%, etc.

[0227] As noted above, stripping and plating may have a dramatic impact on battery performance, particularly regarding dendrite formation for Li-Mg-based electrochemical cells. FIG. 10D demonstrates that this effect may be largely dependent upon the morphology of the anode surface, with more uniform 3D Li-Mg-LTO anode implementations exhibiting substantially less dendritic growth than corresponding baseline Li-Mg anode compositions. In particular, SEM image 1000G depicts a conventional Li-Mg anode surface following the first stripping cycle, and the anode surface clearly remains substantially flat and uniform following such stripping. However, following the first plating cycle as shown in SEM image 1000H, it can be seen that the surface exhibits substantially non-uniform morphology, with bulky regions and gaps extending from and within the anode. By comparison, a 3D anode composition as disclosed herein following the first cycle of stripping (SEM image 10001) and plating (SEM image 1000J) remains much more uniform from a morphological perspective. Since (as dictated by the Sand’s time equation given hereinabove) dendrite formation is significantly impacted by morphology of the stripping / plating process, utilizing a 3D Li- Mg-LTO anode composition as disclosed herein substantially reduces dendrite formation, and correspondingly increases battery cycle life. In one exemplary embodiment, the inventive Li-Mg-LTO 3D anode composition (thickness 120 um) exhibited a cycle life (i.e., retaining above 70% capacity discharge retention) of approximately 310 cycles relative to a corresponding Li-Mg anode composition (thickness 100 um), which exhibited a cycle life of about 250 cycles. Accordingly, embodiments including a Li-Mg-LTO 3D anode composition and structure are characterized by improved stability, safety, and lower cost than conventional Li-Mg anodes.EXAMPLE 4. Cathode discharge capacity and capacity retention of lithium-based coin cells including a freestanding Li-Al-Mg ternary alloy anode.

[0228] FIG. 11 A-l IB show plots 1100A-1100B illustrating cathode discharge capacity and capacity retention of lithium-based coin cells including a freestanding Li- Al-Mg ternary alloy anode, according to some implementations. The aluminum content in the example Li-Al-Mg ternary alloy anode was approximately 15 wt%. The magnesium content in the example Li-Al-Mg ternary alloy anode was approximately 15 wt%. Accordingly, the lithium content in the example Li-Al-Mg alloy anode was approximately 70 wt%.

[0229] Cathode discharge capacity and capacity retention at C / 3 rate of the example lithium-based coin cells with freestanding Li-Al-Mg ternary alloy anodes were compared with cells including a freestanding 90 wt% Li-10 wt% Mg alloy anode. The cathode loading was approximately 7 mg / cm2. A Celgard PP2075 separator was disposed between the cathode and anode. The E / S ratio was approximately 5 ml / g sulfur. The N / P ratio was between approximately 2.4 and approximately 2.6.

[0230] Referring to FIGS. 11 A-l IB, cathode discharge capacity and capacity retention associated with the lithium-based cells with the freestanding Li-Al-Mg ternary alloy anode was comparable to that of the cells including the reference freestanding 90 wt% Li - 10 wt% Mg alloy anode. At approximately 80% capacity retention, the discharge capacity was greater than approximately 500 mAh / g through approximately 150 cycles. Accordingly, the lithium content in freestanding Li-Mg alloys may be reduced to approximately 70 wt% by including a ternary alloying element including aluminum. Additionally, undesirable prolonged activation was not observed during testing of lithium-based coin cells including Li-Al-Mg alloys with a lithium content of approximately 70 wt%.EXAMPLE 5. Cathode discharge capacity and capacity retention of lithium-based coin cells including a freestanding Li-Si-Mg ternary alloy anode.

[0231] FIGS. 12A-12C show plots 1200A-1200C illustrating cathode discharge capacity, capacity retention, and Coulombic efficiency of lithium-based coin cells including a freestanding Li-Si-Mg ternary alloy anode, according to some implementations. The silicon content in the example Li-Si-Mg ternary anode was approximately 20 wt%. The magnesium content in the example Li-Al-Mg ternary alloy anode was between approximately 15 wt% and approximately 25 wt%. Accordingly, the lithium content in the example Li-Si-Mg ternary alloy anode was between approximately 55 wt% and approximately 65 wt%.

[0232] Cathode discharge capacity and capacity retention at C / 3 rate of the example lithium-based coin cells with freestanding Li-Si-Mg ternary alloy anodes was compared with cells including a freestanding 90 wt% Li-10 wt% Mg alloy anode. The cathode loading was approximately 7 mg / cm2. A Cclgard PP2075 separator was disposed between the cathode and anode. The E / S ratio was approximately 5 ml / g sulfur. The N / P ratio was approximately 2.4.

[0233] Referring to FIGS. 12A-12C, cathode discharge capacity associated with of the lithium-based cells with the freestanding Li-Si-Mg ternary alloy anode was comparable to that of the cells including the reference freestanding 90 wt% Li - 10 wt% Mg anode. At approximately 80% capacity retention, the discharge capacity was greater than approximately 500 mAh / g. However, the cells including the reference freestanding 90 wt% Li - 10 wt% Mg alloy anode were relatively more stable through approximately 175 cycles. Accordingly, the lithium content in freestanding Li-Mg alloys may be reduced to between approximately 55 wt% and approximately 65 wt% by including a ternary alloying element including silicon. Additionally, undesirable prolonged activation was not observed during testing of lithium-based coin cells including Li-Si-Mg alloys. As can be seen in FIG. 12C, the inventive biphasic Li-Mg-Si alloys also exhibit similar Coulombic efficiency characteristics as a baseline pure Li-Mg alloy with about 90 wt% lithium and about 10 wt% magnesium. While the efficiency varies slightly with different ratios of Li, Mg, and Si , e.g., with different examples having 10 wt% Mg-20 wt% Si; 15 wt% Mg-20 wt% Si, or 20 wt% Mg-20 wt% Si, and the balance of the compositions being lithium, all exhibited slightly lower Coulombic efficiency than the reference 90 wt% Li - 10 wt% Mg alloy anode.EXAMPLE 6. Cathode discharge capacity, capacity retention, and polarization of lithium-based coin cells including a freestanding Li- Mg / C alloy anode.

[0234] FIG. 13A-13E show plots 1300A-1300F illustrating cathode discharge capacity, capacity retention, polarization, and Coulombic efficiency of lithium-based coin cells including a freestanding Li-Mg / C alloy anode, according to some implementations. Graphite was used as the representative carbon material. The graphite content in the example Li- Mg / C anode was approximately 1 wt%.

[0235] Cathode discharge capacity and capacity retention at C / 3 rate of the example lithium-based coin cells with freestanding Li- Mg / C alloy anodes was compared with cells including a freestanding 90 wt% Li- 10 wt% Mg alloy anode. The cathode loading was approximately 7.4 mg / cm2. A Celgard PP2075 separator was disposed between the cathode and anode. The E / S ratio was approximately 5 pl / g sulfur. The N / P ratio was approximately 3.5.

[0236] Referring to FIGS. 13A-13B, cathode discharge capacity associated with of the lithium-based cells including the freestanding Li-Mg / C alloy anode was comparable to that of the cells including the reference freestanding 90 wt% Li - 10 wt% Mg alloy anode. At approximately 80% capacity retention, the discharge capacity was approximately 400 mAh / g. Additionally, undesirable prolonged activation was not observed during testing of lithium-based coin cells including Li- Mg / C alloys.

[0237] Referring to FIGS. 13C-13E, a reduction in cell polarization was observed at 1C rate with the cells including the Li-Mg / C alloy anode, which suggests that the addition of carbon in a Li-Mg alloy decreases the overpotential and mitigates the loss in energy density upon cycling and improves the electrochemical performance of lithium-based batteries. Notably, the graphite is characterized by a three-dimensional (3D) geometry, which advantageously provides improved accessibility to the anode. Acting as an electronic filler, the graphite diminishes diffusion limitations in the bulk of the anode structure. In addition, polarization is reduced relative to the baseline Li-Mg alloy composition.

[0238] To further evaluate the potential of the inventive Li-Mg-C 3D anode composite, rate testing was conducted on on symmetric cells at a very high current density of about 24 mA / cm2. As shown in FIG. 13E, the Li-Mg-C graphite 3D composite can sustain veryhigh current density while still producing less impedance than the Li-Mg baseline composition. Indeed, the potential produced by the Li-Mg-C alloy anode is more significantly stable than the potential generated by the baseline Li-Mg alloy at a charge / discharge rate in the range of 4C-6C, and especially 4C-5C.

[0239] Referring to FIG. 13F, it is clear that the exemplary Li-Mg / C alloy anode is characterized by substantially similar Coulombic Efficiency as the reference freestanding 90 wt% Li - 10 wt% Mg alloy anode.

[0240] In various approaches, the inventive structures, compositions, configurations, etc. described herein may be implemented in electrochemical cells of various types for practical utilization in a wide variety of applications. Without limitation, exemplary electrochemical cell configurations that may utilize any combination of features described herein, may be in the form of a pouch, a coin, a prismatic cell, a cylindrical configuration, or any suitable equivalent(s) thereof that would be appreciated by those having ordinary skill in the art upon reading the present disclosure.

[0241] With reference to electrochemical cells having a pouch cell arrangement 1400, and as shown according to exemplary embodiments in FIGS. 14A-14C, an electrochemical cell includes a cathode 1410a and an anode 1410b positioned on opposing sides of the pouch cell arrangement 1400, and separated (physically and / or chemically) by a separator 1410c. The anode 1410b and cathode 1410a are electronically coupled via an electrolyte 1410f present in the pouch cell arrangement 1400. Moreover, each electrode is electronically coupled to an external environment of the pouch cell arrangement 1400 via a current collector and corresponding terminal, i.e. the cathode 1410a is coupled to the external environment via cathode current collector 1410d and cathode terminal 1406a, while the anode 1410b is coupled via anode current collector 1410e and anode terminal 1406b. The foregoing structures are enclosed, encased, or otherwise spatially fixed and contained via a pouch 1402 surrounding the components.

[0242] The pouch 1402, according to various embodiments, may take any suitable form that would be understood by those having ordinary skill in the ail upon reading the present disclosure, such as a wrapping, a coating, an enclosure (soft or hard), a compressive structure (such as a metal band or mesh), etc. as would be understood by those having ordinary skill in the art upon reading the present disclosure.

[0243] Moreover, as shown in FIG. 14B, the anode terminal 1406b and cathode terminal 1406a extend through the pouch 1402, providing electronic coupling between interior and exterior environments of the pouch cell arrangement 1400. Note the anode terminal 1406b may alternatively be positioned on a same side, or an opposite side, of the pouch cell arrangement 1400 relative to the cathode terminal 1406a. Moreover, the relative position of the anode terminal 1406b and the cathode terminal 1406a may be switched relative to the arrangement shown in FIGS. 14B and 14C, according to alternative implementations and without departing from the scope of the presently described inventive concepts.

[0244] As noted in FIGS. 14A and 14B, the illustrative pouch cell arrangement 1400 may be wound around, e.g., its longitudinal axis, to form a spiral, folded, pleated, rolled, or otherwise at least partially overlapping configuration of the above-referenced electrochemical cell components. In preferred implementations, winding the pouch cell arrangement 1400 yields a configuration 1420 known as a “jellyroll”, Shown schematically in FIG. 14C.

[0245] Turning now to FIGS. 15 A and 15B, which depict a simplified schematic of an electrochemical cell configured according to a coin cell arrangement 1500 is aptly named for its substantially flat, cylindrical shape as shown in FIG. 15A. According to various embodiments, the cylindrical cell arrangement 1500 includes a can 1502 and cap 1504 which protect the components placed therein from mechanical damage, chemical damage (e.g. corrosion, oxidation, etc.) electrical damage, etc. and also prevent leakage of compounds within the cylindrical cell arrangement 1500 into the environment.

[0246] Coupled to the cap 1504 is an anode terminal 1506b, and likewise coupled to the can 1502 is a cathode terminal 1506a (not shown in FIG. 15B). Preferably, these terminals have a composition suitable for conducting electricity generated within the coin cell arrangement 1500 to an appropriately connected or coupled output, and may be inserted into a circuit to provide power thereto, as would be appreciated by those having ordinary skill in the art upon reading the present descriptions. Exemplary compositions suitable for use in cathode terminal 1506a and anode terminal 1506b include electrically conductive metals, such as copper, nickel, etc. as known in the art, electrically conductive carbonaceous materials, such as graphene, etc. as known in the art, or any other suitableequivalent thereof that would be appreciated by a skilled artisan upon reading the present disclosures.

[0247] Turning now to FIG. 15B, a plurality of components that may be included in a coin cell arrangement 1500 are shown according to an exploded view consistent with various embodiments of the presently described inventive concepts. It shall be appreciated that components such as washer / spring 1520, spacer 1522, and gasket 1524, represented by dotted outlines, are optional and may, but need not, be included in accordance with the inventive concepts disclosed herein. However, it shall also be appreciated that, depending on the intended application for the coin cell arrangement 1500, washer / spring 1520, spacer 1522, and / or gasket 1524 may advantageously convey mechanical strength, or convey advantageous electrical properties, on the coin cell arrangement 1500. For instance, washer / spring 1520 and / or gasket 1524 may help secure the other depicted components in place, facilitating desired operation of the coin cell arrangement 1500. Similarly, spacer 1522 may cushion the anode 1510b from friction or compressive force from the washer / spring 1520, and / or be formed from a material that facilitates conduction of heat and / or electricity from within the coin cell arrangement 1500 to the anode terminal 1506b, according to the configuration shown in FIG. 15B. Of course, those having ordinary skill in the art will appreciate various advantages that may be realized via inclusion of washer / spring 1520, spacer 1522, and / or gasket 1524, in various implementations, based on knowledge generally available at the time of the present disclosure’s filing date.

[0248] With continuing reference to FIG. 15B, illustrative coin cell arrangement 1500 features internal components including an anode 1510b positioned toward an opposing end of the coin cell arrangement as a cathode 1510a, with a separator 1510c and electrolyte 1510f positioned therebetween. As with all electrochemical cell arrangements shown in FIGS. 14A-17 and consistent with corresponding descriptions thereof provided herein, the anode 1510b, cathode 1510a, separator 1510c, and electrolyte 1510f may each be characterized by any composition as known in the art or as described herein that a skilled artisan would appreciate as suitable for the respective function thereof in an electrochemical cell, upon reading the present disclosure and without departing from the scope of the presently described inventive concepts. Several such exemplarycompositions are provided hereinbelow, and others may be set forth elsewhere in the detailed descriptions of the inventive concepts instantly set forth. Unless expressly admitted as being known in the ait, it shall be understood that any such exemplary composition described for any of the components of electrochemical cell arrangements 14A-17 is not admitted as being so well-known, but rather is considered part of the inventive concepts presented herein.

[0249] In other approaches, electrochemical cells may be characterized by a cylindrical cell arrangement 1600, e.g., as shown according to illustrative implementations in FIG. 16A (external view) and 16B (cut-out view), includes a can 1602 and a cap 1604 that contain and protect other components internal to the cylindrical cell configuration, in similar manner as described herein regarding coin cell arrangements such as coin cell arrangement 1500 shown in FIGS. 15A and 15B. Also similar to other arrangements described herein, the cap 1604 and can 1602 each respectively include a terminal configured to conduct electricity generated within the cylindrical cell arrangement 1600 to an external environment, output device electrically coupled to the cylindrical cell arrangement 1600, etc., according to various embodiments and as would be appreciated by those having ordinary skill in the art upon reading the present disclosure. As shown in FIG. 16B, cap 1604 includes a cathode terminal 1606a, while can 1602 includes an anode terminal 1606b (not shown in FIG. 16B), positioned at substantially opposite ends of the cylindrical cell arrangement 1600. Of course, the relative position of the cathode terminal 1606a and anode terminal 1606b may be swapped, according to alternative embodiments of the cylindrical cell arrangement 1600.

[0250] With continuing reference to FIG. 16B, the illustrative cylindrical cell arrangement 1600 includes similar components as described herein with reference to other electrochemical cell arrangements, but structurally arranged in a unique manner. Most notably, while the cathode(s) 1610a and anode(s) 1610b are spatially separated by separator(s) 1610c, there are a plurality of such structures arranged in substantially laminar configuration and wound around a central longitudinal axis of the cylindrical cell arrangement 1600. In this manner, the cathode(s) 1610a and anode(s) 1610b are not positioned proximate to opposing ends of the cylindrical cell arrangement 1600 as is the case for pouch cell arrangement 1400 and coin cell arrangement 1500, but rather presentthroughout a volume of the cylindrical cell arrangement 1600. Regardless, consistent with pouch cell arrangement 1400, the cylindrical cell arrangement 1600 includes a cathode current collector 1610d (not shown in FIG. 16B) and an anode current collector 1610e positioned at opposing ends of the cylindrical cell arrangement 1600 and electrically coupled to a corresponding terminal (i.e., either cathode terminal 1606a or anode terminal 1606b), as would be understood by those having ordinary skill in the art upon reading the present disclosures.

[0251] Now regarding FIG. 17, a simplified schematic of an electrochemical cell embodied in a prismatic configuration 1700 is shown, according to one aspect of the presently disclosed inventive concepts. As with other electrochemical cell arrangements described hereinabove, the prismatic cell arrangement 1700 includes a can 1702 and a cap 1704. Unique to the prismatic cell arrangement 1700, the can 1702 and cap 1704 as shown in FIG. 17 are substantially rectangular cuboidal in shape, although those having ordinary skill in the art will appreciate that a unique advantage of prismatic cell arrangements as contemplated herein is nearly unlimited flexibility with respect to the spatial configuration of the can 1702 and cap 1704. The sole limitation on such spatial configuration is the ability to fully enclose and contain the internal components, shown according to one exemplary embodiment with reference to electrode and separator arrangement 1710. This flexibility, in large pail, is due to implementation of electrode and separator arrangements 1710 characterized by a laminar structure including anode(s) 1710b and cathode(s) 1710a physically and / or chemically separated by separator(s) 1710c. While the particular electrode and separator arrangement 1710 shown in FIG. 17 is a multi-layered structure (e.g., composed of a series of thin films deposited sequentially one onto the other) those having ordinary skill in the art will appreciate that according to various implementations the components of the electrode and separator arrangement 1710 (which may include components other than anode 1710b, cathode 1710a, and separator 1710c without departing from the scope of the presently disclosed inventive concepts) may be arranged in a “rolled” configuration such as shown in FIGS. 14C and 16B, or in a folded configuration, a pleated configuration, or any other configuration in which at least portion(s) of the components of the electrode and separator arrangement 1710 at least partially overlap themselves, one another, or both. Furthermore, combinations ofoverlapping arrangements may be implemented in electrode and separator arrangement 1710 without departing from the scope of the presently disclosed inventive concepts.

[0252] Returning to the cap 1704 of exemplary prismatic cell arrangement 1700 shown in FIG. 17, in one illustrative implementation a plurality of terminals including cathode terminal 1706a and anode terminal 1706b are disposed on an external surface of the cap 1704 and electrically coupled to the electrode and separator arrangement 1710, e.g. via one or more current collectors (not shown in FIG. 17) using any suitable means and / or mechanisms that would be understood by those having ordinary skill in the ail upon reading the instant descriptions.

[0253] Several exemplary electrochemical cell arrangements have been shown and described with reference to FIGS. 14A-17, and shall be understood as illustrative rather than limiting on the scope of the inventive concepts presented herein. Moreover, certain arrangements are depicted as including or omitting certain components not expressly shown or described with reference to other arrangements (such as the washer / spring 1420, spacer 1422, gasket 1424, electrolyte 1410f, current collectors 1410d and 1410e, shown with reference to FIG. 14A but not expressly shown or described with reference to other arrangements set forth herein. Despite the particular components shown in FIGS. 14A-17, it shall be understood that any electrochemical cell arrangement, whether in accordance with FIGS. 14A-17 or according to a different electrochemical cell arrangement, may include any suitable combination of components described with reference to any single FIG., or components not shown in any of the FIGS., but which would be appreciated as suitable for creating a functioning electrochemical cell by a person having ordinary skill in the art upon reading the instant descriptions.

[0254] Of course, the various exemplary embodiments of electrochemical cells arranged according to different configurations shown in FIGS. 14A-17 and described hereinabove are provided for illustrative purposes, and should not be interpreted as limiting on the scope of electrochemical cells in which the inventive anode structures and compositions presently disclosed may be implemented. For instance, in various approaches different electrochemical cell configurations may be used together, in any combination, to provide power to one or more machines.

[0255] Moreover, the exemplary electrochemical cell configurations described hereinabove may be modified in any suitable manner known in the art without departing from the scope of the inventive concepts described herein. For instance, various components shown above in FIGS. 14A-17 may be modified, substituted, omitted, supplemented, etc. in any manner that a skilled artisan reading the present disclosure would appreciate as suitable for producing a working electrochemical cell, without extending beyond the scope of the presently described inventive concepts.

[0256] For instance, according to various embodiments, electrochemical cells implemented in accordance with the presently described inventive concepts may include one or more (preferably at least two) electrodes, which may individually be characterized as anode(s), or cathode(s), e.g., according to electrochemical function within the overall cell, and may be formed from any suitable material(s) known in the art and appreciated, upon reading the present disclosure, as suitable for use in combination with other structures and compositions in the exemplary electrochemical cell and in accordance with the inventive concepts provided herein.

[0257] In some approaches, either or both electrode types may be configured in the form of a three-dimensional, monolithic structure that is “free-standing”. In other words, the “free-standing” electrode is “structurally self-supporting”, such that no separate substrate, framework, scaffold, foam, matrix, current collector, supporting fluid, etc. is necessary for the monolith to support its own weight and maintain defining physical characteristics (e.g., density, volume, porosity, physical dimensions, shape, chemical composition, etc.) when deposited, positioned, or otherwise placed in a working environment such as an electrochemical cell. Of course, the inventive concepts presented herein should not be interpreted as being limited in any way to inclusion of or requirement for “free standing” electrode(s), but should be understood as allowing for such structures where advantageous to the specific application(s) or intended utility for the inventive electrochemical cell of interest.

[0258] Where a “free standing” electrode structure is implemented, corresponding electrochemical cells may, and preferably do, omit a distinct current collector (or at least a distinct anode current collector), according to select implementations. Indeed, even where no “free standing” electrode structure is present, electrochemical cells inaccordance with the inventive concepts described herein may still omit a distinct current collector structure or component.

[0259] For instance, according to certain implementations, the electrode itself may serve as the current collector, or the separator(s) may serve as the current collector, in addition to fulfilling additional functions described herein with respect to the separator, such as physically, chemically, electrically, etc. segregating various components of the electrochemical cell from one another to avoid undesirable chemical reactions, physical phenomena, etc. as would be understood by a person having ordinary skill in the ail upon reading the present disclosure. Again, the inventive concepts presented herein shall be understood as including, but not requiring, omission of distinct current collector components, according to various embodiments.

[0260] Accordingly, electrodes of the illustrative electrochemical cell implementations may be distinct structures, such as three dimensional monoliths, which may optionally be porous, have surface(s) thereof functionalized in order to enhance, suppress, or otherwise modify functional characteristics thereof (such as permeability, reactivity, etc. to select chemical species present within the electrochemical cell) without limitation. Electrodes may optionally or additionally include indeterminate structures, such as solutions that exhibit functional characteristics of monolithic electrode structures, but are present partially or wholly in the form of a solution. Further still, electrodes may be physically arranged in various configurations, such as thin films which may be sprayed or deposited on a suitable substrate; a one or more (flat) layers which may be sprayed or deposited on a suitable substrate or as free-standing structures; as a plurality of rows and / or channels (e.g., as may be formed in a suitable electrode material, or as may be formed as a result of stacking various layers of an electrochemical cell, rolling a multilayered electrochemical cell, etc.) as would be understood by those having ordinary skill in the art upon reading the present disclosure..

[0261] Optionally, electrodes may be coated with a protective layer designed to facilitate or mitigate predetermined chemical or physical interactions with other components of the electrochemical cell, such as reactions that consume electrode active material, form dendritic structures extending from the electrode, etc. as would be understood by those having ordinary skill in the art upon reading the present disclosure. In like manner, anelectrode may include a plurality of particles (e.g. of active material) dispersed within or throughout the volume of a binder such as a polymer matrix, and the binder may be or include material(s) that facilitate or mitigate desired or undesired interactions within the electrochemical cell, respectively. In still more approaches, electrolyte(s) may be operatively, chemically, or electrically coupled to a membrane or membrane(s) configured (e.g., according to physical characteristics such as porosity, lack of porosity, spatial arrangement, surface area, etc., or chemically configured, e.g. according to chemical composition, specific functionalization (e.g., of surface(s) of the membrane), etc.) to isolate the electrolyte and / or chemical species formed or derived therefrom from other components of the electrochemical cell.

[0262] In particularly preferred approaches, electrodes may include one or more carbonaceous materials such as shown in FIG. 18 and described in greater detail hereinbelow.

[0263] It shall be appreciated that electrolytes in accordance with the presently disclosed inventive concepts may have any suitable chemical composition that would be understood by a person having ordinary skill in the art taking into consideration the particular context of the electrochemical cell, e.g., the chemical composition and structural arrangement of various other components included in the electrochemical cell.

[0264] Similarly, electrolyte(s) present in various electrochemical cells may be in liquid form, may be or include solid state electrolyte composition(s), may be or include gelphase or gel-based electrolytes (such as gel polymer electrolytes), or any combination thereof that would be appreciated by those having ordinary skill in the art upon reading the present disclosure. Similarly, electrolytes may include semi-solid compositions such as gels, slurries, suspensions, etc. as would be appreciated by those having ordinary skill in the ail upon reading the instant disclosure.

[0265] Separator(s), which may also be omitted in accordance with certain aspects of the inventive concepts described herein, may be or include any suitable composition or structure known in the art and which skilled artisans reading the present disclosure will appreciate are compatible with the inventive compositions and / or structures described herein. For instance, separator(s) may include impermeable, solid structures, semi- permeable membranes, selectively permeable compositions (i.e., compositions that arepermeable to one or more predetermined chemical species, but impermeable or substantially impermeable to select, or all, other chemical species, according to various embodiments). For example, separators may be configured to physically, chemically, electrically, or otherwise functionally separate or segregate different components of the electrochemical cell from one another in order to avoid undesirable chemical reactions (such as parasitic reactions between electrolyte or derivatives thereof and electrodes, polysulfide shuttling, dendrite formation, etc. as would be understood by those having ordinary skill in the art upon reading the instant descriptions).

[0266] In addition, the exemplary electrochemical cells, in any configuration described herein or equivalents thereof that would be appreciated by those having ordinary skill in the art upon reading the instant disclosure, may include one or more mechanisms for mitigating or preventing polysulfide shuttling, dendrite formation, parasitic reactions between electrode(s) and electrolyte(s) (as well as species formed or derived from electrodes or electrolytes during operation of the electrochemical cell), or other chemical species present in the electrochemical cell environment. These mechanisms may be inherent to one or more of the exemplary structures described hereinabove (e.g., electrodes, separators, electrolytes, etc.), or may be specifically configured via specific modification, functionalization, structural arrangement, etc. of the particular components of the electrochemical cell. Any such characteristics, whether inherently present or specifically configured, are described in greater detail herein in accordance with various exemplary embodiments of the inventive concepts presently disclosed.

[0267] From the foregoing general descriptions and corresponding drawings, skilled artisans reviewing the present application will appreciate that, according to different implementations, electrochemical cells as described herein include a variety of components which each have a specific, core role in function of the electrochemical cell as a whole (e.g., electrodes facilitating electrical contact between electrolyte and an environment external to the electrochemical cell; separators serving to isolate or segregate various components, chemical species, etc. from one another within the electrochemical cell environment; and electrolyte facilitating charge transfer between electrodes of the electrochemical cell), the various components may optionally serve or convey one or more additional functions to the electrochemical cell. For instance, and asmentioned above, electrodes or separators may serve, in addition to their respective core roles, as current collectors, allowing omission of separate (often heavy, metal) structures dedicated to collecting current generated by the electrochemical cell.

[0268] In various aspects, any one or more component(s) of the electrochemical cell arrangements described herein may include one or more carbonaceous materials, including but not limited to those shown in FIG. 18. For example, certain components may include carbonaceous materials, carbonaceous materials may be included in addition to the various components shown and described with reference to FIGS. 14A-17, or both, as would be appreciated by those having ordinary skill in the art upon reading the present disclosures. In myriad embodiments, exemplary carbonaceous materials may include, without limitation, carbon black, carbon nano-onions (CNOs), necked CNOs, carbon nanospheres, graphite, pyrolytic graphite, graphene, graphene nanoparticles, graphene platelets, three-dimensional (3D) graphene, graphene oxides, fullerenes, hybrid fullerenes, single-walled nanotubes, multi-walled nanotubes, carbon dots, carbon spheres, porous carbons, carbon fibers, etc. as would be understood by skilled artisans upon reading the present descriptions. Additional details regarding the fabrication of select carbonaceous materials and characteristics thereof, particularly those shown in FIG. 18, are provided by Li, et al. “Synthesis, modification strategies and applications of coalbased materials”, Fuel Processing Tech., 230:1, 107203 (June 2022) (http s : / / doi .org / 10.1016 / j .fuproc .2022.107203 ) .

[0269] Moreover, the exemplary components of electrochemical cells described hereinabove, particularly as shown in FIGS. 14-17, may be present in a single cell “stack” (e.g., two opposing electrodes with corresponding separator, electrolyte, etc. arranged therebetween) or in a repeating (e.g., laminar) structure, according to various embodiments. A simplified repeating structure may, for example, include a first cathode (optionally coupled to a first cathode current collector) at one end of the electrochemical cell, which is immediately adjacent to a first electrolyte, which in turn is immediately adjacent to a first separator, which in turn is immediately adjacent to a second electrolyte, which in turn is immediately adjacent to a first anode (optionally coupled to a first anode current collector) positioned toward an opposing end of the electrochemical cell as the first cathode, collectively forming a single electrochemical cell layer. The repeatingstructure may further comprise additional electrolyte, separator, and electrode structures in a similar manner to form a multilayered, repeating pattern within the resulting electrochemical cell.

[0270] Whether including repeating structures or not, in various approaches, electrochemical cells may be manipulated, configured, arranged, etc. during fabrication of a larger structure (such as a battery). For instance, and as will be appreciated by those having ordinary skill in the art upon reviewing the inventive concepts described herein, in some approaches an electrochemical cell such as shown in FIG. 14B may be “rolled” around a central axis, forming a so-called “jelly roll” configuration, as shown in FIG.14C according to one embodiment, which may be particularly suitable for certain arrangements or applications, such as for cylindrical or prismatic electrochemical cell embodiments, among others that skilled artisans will comprehend upon reviewing the present disclosure.

[0271] While the foregoing electrode, electrolyte, and separator components are the most common and critical aspects of the exemplary electrochemical cell as described herein, it shall be appreciated that according to various implementations electrochemical cells may, or may not, include any suitable combination or permutation of additional or alternative components, such as membranes, cans, caps, casings, wrappings, springs, wires, spacers, tabs, contacts, leads, gaskets, compressive structures or mechanisms, etc. as would be understood by a person having ordinary skill in the art upon reading the present descriptions.

[0272] Moreover, it shall be appreciated that persons having ordinary skill in the art may employ the various electrochemical cell embodiments described herein, including but not limited to coin cell arrangements, cylindrical cell arrangements, pouch cell arrangements, prismatic cell arrangements, etc. or any suitable equivalent(s) thereof that would be understood by said skilled artisan upon reading the present disclosure, in any effective permutation or combination, without departing from the scope of the inventive concepts in this disclosure. For instance, multiple of the same arrangements, combinations of different arrangements, or both, may be employed, e.g., to form a battery, or an assembly (e.g., a battery module, or a battery pack, etc. as would be understood by persons having ordinary skill in the art upon reading the present disclosure).

[0273] For example, those having ordinary skill in the art will appreciate that different arrangements described herein may have different advantages or disadvantages in the context of different applications, and may choose to employ the most advantageous arrangements of the particular application of interest. Additionally or alternatively, a skilled artisan may include different arrangements to provide robustness across different applications or working conditions to the resulting structure, providing flexibility of use, redundant failure points, or other advantage that would be understood by those having ordinary skill in the art in light of the particular application in mind.

[0274] As a concrete example, cylindrical cells are, relative to other arrangements described herein, are prone to cracking. Accordingly, a cylindrical cell arrangement such as shown in FIGS. 16A and 16B may not be applicable to or compatible with a prismatic cell configuration such as shown in FIG. 17, depending on the intended application for a given electrochemical cell, such as applications involving substantial and / or frequent application of mechanical forces (e.g. rapid acceleration / deceleration, vibration, etc. such as often experienced in vehicular applications. Similarly, pouch cell arrangements are particularly sensitive to volumetric expansion and contraction that occurs during natural operation and cycling of the electrochemical cell, and may require or benefit from additional support such as a compressive structure or internal mechanism (e.g. a polymeric support network such as described in U.S. Patent No. 12,009,953 granted June 11, 2023 and entitled “Internally enclosed support system for batteries, fabrication techniques and applications for the same”, the contents of which are herein incorporated by reference).

[0275] Moreover, while exemplary electrochemical cell arrangements expressly described herein and shown in the various FIGS, include a pouch cell arrangement, a coin cell arrangement, a cylindrical cell arrangement, and a prismatic cell arrangement, other arrangements and / or components may be utilized without departing from the scope of the inventive concepts presented in this disclosure. For example, electrochemical cell arrangements may additionally or alternatively include components or be characterized by arrangements such as chassis, trays, packs, modules, assemblies, casings, etc. as would be understood by those having ordinary skill in the art upon reading the present disclosure.

[0276] Of course, the electrochemical cells described herein, according to various embodiments, may include external componcnt(s) at least partially surrounding the electrochemical cell. For instance, exemplary external components may be selected from the group consisting of an external casing enclosing the electrochemical cell, a module operatively coupled to the electrochemical cell, an assembly operatively coupled to the electrochemical cell, a pack enclosing the electrochemical cell, a pouch enclosing the electrochemical cell, a can enclosing the electrochemical cell, a tray operatively coupled to the electrochemical cell, a pan operatively coupled to the electrochemical cell, and combinations thereof. The assembly may comprise: a parallel assembly, an in-series assembly, or a cell-to-chassis assembly. In still further embodiments, an electrochemical cell may be integrated into, or may be a part of, a structural component of the device to which the electrochemical cell is providing power, such as being integrated into a structural component of an electric vehicle.

[0277] The presently described inventive concepts include fabricating electrochemical cells of various types using additive manufacturing techniques, injection molding techniques, compression molding techniques, hybrid injection / compression molding techniques, preforming techniques, hand layup techniques, casting techniques, infusion techniques, sintering techniques, or any combination thereof that would be appreciated by a skilled artisan upon reading the present disclosure.

[0278] As used herein, a phrase referring to “at least one of’ or “one or more of’ a list of items refers to any combination of those items, including single members. For example, “at least one of: a, b, or c” is intended to cover the possibilities of: a only, b only, c only, a combination of a and b, a combination of a and c, a combination of b and c, and a combination of a and b and c. Unless otherwise specified in this disclosure, for construing the scope of the term “about” or “approximately,” the error bounds associated with the values (dimensions, operating conditions etc.) disclosed is ± 10% of the values indicated in this disclosure. The error bounds associated with the values disclosed as percentages is ± 1% of the percentages indicated. The word “substantially” used before a specific word includes the meanings “considerable in extent to that which is specified,” and “largely but not wholly that which is specified.”

[0279] Various modifications to the implementations described in this disclosure may be readily apparent to persons having ordinary skill in the art, and the generic principles defined herein may be applied to other implementations without departing from the spirit or scope of this disclosure. Thus, the claims are not intended to be limited to the implementations shown herein but are to be accorded the widest scope consistent with this disclosure, the principles and the novel features disclosed herein.

[0280] Additionally, various features that are described in this specification in the context of separate implementations also can be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation also can be implemented in multiple implementations separately or in any suitable subcombination. As such, although features may be described above in combination with one another, and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.

[0281] Similarly, while operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. Further, the drawings may schematically depict one more example processes in the form of a flowchart or flow diagram. However, other operations that are not depicted can be incorporated in the example processes that are schematically illustrated. For example, one or more additional operations can be performed before, after, simultaneously, or between any of the illustrated operations. In some circumstances, multitasking and parallel processing may be advantageous.Moreover, the separation of various system components in the implementations described above should not be understood as requiring such separation in all implementations, and it should be understood that the described program components and systems can generally be integrated together in a single product or packaged into multiple products.

Claims

CLAIMSWhat is claimed is:

1. A composite anode associated with a lithium-based battery, the composite anode including a Li-Mg-X ternary alloy, and one or more of a lithium-ion conducting material or an electron conducting material.

2. The composite anode of claim 1, wherein X is a ternary component of the Li-Mg-X ternary alloy, and wherein a ternary component content in the Li-Mg-X ternary alloy is between approximately 1 wt% and approximately 90 wt%.

3. The composite anode of claim 1, wherein X includes one or more ternary components selected from: calcium (Ca), gallium (Ga), boron (B), tin (Sn), aluminum (Al), indium (In), bismuth (Bi), antimony (Sb), tellurium (Te), carbon (C), silicon (Si), bismuth telluride (BiTe), antimony telluride (SbTe), zinc (Zn), or any combination thereof.

4. The composite anode of claim 3, wherein the one or more ternary components are substantially homogenously distributed throughout a bulk of the composite anode.

5. The composite anode of claim 1, wherein the Li-Mg-X ternary alloy includes a Li-Mg alloy phase and a Li-X alloy phase.

6. The anode of claim 5, wherein a weight ratio of the Li-Mg alloy phase to the Li-X alloy phase is between approximately 0.1 and approximately 20.

7. The composite anode of claim 1, wherein the lithium-ion conducting material includes: bismuth telluride (BiTe), antimony telluride (SbTe), lithium-doped tritelluride (LiTea), lithium titanate (Li^isOn, “LTO”), lithium lanthanum zirconiumoxide (LivLaaZ On. “LLZO”), lithium phosphide (LiaP), molybdenum oxide (MoO), molybdenum disulfide (M0S2), or any combination thereof.

8. The composite anode of claim 1, wherein the electron conducting material includes carbon.

9. The composite anode of claim 1, wherein the Li-Mg-X alloy includes carbon.

10. The composite anode of claim 9, wherein the carbon includes: graphite, graphene, carbon nanotubes, hollow porous multi-nanochannel carbon fiber (HTCNF), non-graphitizing carbon, carbon nanofibers, or any combination thereof.

11. The composite anode of claim 9, wherein the carbon forms an electrochemically inert phase in the Li-Mg-X alloy.

12. The composite anode of claim 9, wherein the carbon is substantially homogenously distributed throughout a bulk of the anode.

13. The composite anode of claim 1, wherein a lithium content in the anode is between approximately 10 wt% and approximately 90 wt%.

14. The composite anode of claim 1, wherein a magnesium content in the anode is a nonzero amount up to approximately 50 wt%.

15. The composite anode of claim 1, further including one or more of alumina (AI2O3) or titanium dioxide (TiCh).

16. The composite anode of claim 1, wherein an amount of the lithium-ion conducting material is between approximately 1 wt% and approximately 90 wt%.

17. The composite anode of claim 1 , wherein a weight ratio of the Li-Mg alloy to the lithium-ion conducting material is between approximately 1 and approximately 9.

18. The composite anode of claim 1, wherein a magnesium content in the Li- Mg alloy is between approximately 5 wt% and approximately 50 wt%.

19. The composite anode of claim 1, wherein the composite anode is a freestanding, three-dimensional monolith.

20. The composite anode of claim 1, further including a polymer coating including one or more of polyvinylidene fluoride (PVDF), pentaerythritol tetraacrylate (PETEA), or polyethylene glycol dimethacrylate (PEGDMA) disposed on the composite anode.

21. The composite anode of claim 20, wherein a thickness of the polymer coating is between approximately 100 nm and approximately 10 pm.

22. The composite anode of claim 1, wherein a thickness of the composite anode is approximately 100 pm.

23. An electrochemical cell comprising the composite anode as recited in claim 1.

24. The electrochemical cell as recited in claim 23, wherein the electrochemical cell is characterized by a coin configuration.

25. The electrochemical cell as recited in claim 23, wherein the electrochemical cell is characterized by a cylindrical configuration.

26. The electrochemical cell as recited in claim 23, wherein the electrochemical cell is characterized by a prismatic configuration.

27. The electrochemical cell as recited in claim 23, wherein the electrochemical cell is characterized by a pouch configuration.

28. The electrochemical cell as recited in claim 23, wherein the electrochemical cell neither includes nor is coupled to any distinct structure serving as a current collector other than the three-dimensional (3D) monolith.

29. A lithium-based battery including: a freestanding composite anode including a Li-Mg-X ternary alloy and one or more of a lithium-ion conducting material or an electron conducting material; and a fluorinated ether electrolyte.

30. The lithium-based battery of claim 29, wherein the fluorinated ether electrolyte includes one or more of: approximately 50:25:25 (vol%) 1 ,2-dimethoxyethane (DME): 1,3-dioxolane (DOL): bis (2,2,2-trifluoroethyl) ether (BTFE) and including approximately 0.4 M LiTFSI and approximately 2 wt% LiNOc approximately 50:25:25 (vol%) DME : DOL: 1 , 1 ,2,2-tetraethoxyethane (TEE) and including approximately 0.4 M LiTFSI and approximately 2 wt% LiNOi: approximately 50:25:25 (vol%) DME : DOL: 1 , 1 ,2,2-tetrafluoroethyl 2,2,2- trifluoroethyl ether (TFETFE) and including approximately 0.4 M LiTFSI and approximately 2 wt% LiNOa; approximately 60:20:10:10 (vol%) DME : DOL: TEE: TFETFE and including approximately 0.4 M LiTFSI and approximately 2 wt% LiNO.?; approximately 50:25:25 (vol%) DME : DOL: l,l,2,2-tetrafluoroethyl-2,2,3,3- tetrafluoropropyl ether (TTE) and including approximately 0.4M LiTFSI and approximately 2 wt% LiNOa; approximately 50:25:25 (vol%) DME : DOL: 1 fluorinated 1 ,4-dimethoxylbutane (FDMB) including approximately 0.4 M LiTFSI and approximately 2 wt% LiNOa; or approximately 1.0 M LiTFSI in approximately 50:50 (vol%) DOL: BTFE.

31. The lithium-based battery of claim 29, wherein a thickness of the composite anode is approximately 100 pm.

32. The lithium-based battery of claim 29, further including a polymer coating disposed on the composite anode.

33. The lithium-based battery of claim 32, wherein the polymer coating includes one or more of polyvinylidene fluoride (PVDF), pentaerythritol tetraacrylate (PETEA), or polyethylene glycol dimethacrylate (PEGDMA).

34. The lithium-based battery of claim 32, wherein a thickness of the polymer coating is between approximately 100 nm and approximately 10 pm.

35. The lithium-based battery of claim 29, further including a cathode disposed opposite to the composite anode.

36. The lithium-based battery of claim 35, wherein the cathode includes: one or more porous carbon layers including porous carbon agglomerates of porous carbon primary nanoparticlcs, wherein a respective porous carbon primary nanoparticle includes: an inner porous shell disposed about a center of the respective porous carbon primary nanoparticle and enclosing an inner porous carbon region; an outer porous shell enclosing an outer porous carbon region disposed between the inner shell and the outer shell; and an interconnected porous network disposed in and in fluid communication with the inner and outer porous carbon regions.

37. The lithium-based battery of claim 36, wherein the inner carbon region and the outer carbon region are characterized by an average pore size and an average pore density associated with each region.-SO-38. The lithium-based battery of claim 37, wherein the average pore size decreases along a radial direction from the center to the outer porous shell.

39. The lithium-based battery of claim 36, further including one or more intermediate porous shells disposed between the inner porous shell and the outer porous shell, wherein each of the intermediate porous shells encloses a respective intermediate porous carbon region.

40. The lithium-based battery of claim 36, wherein the porous carbon agglomerates are characterized by a Raman spectroscopy signature with an ID / IG ratio between approximately 0.95 and approximately 1.05.

41. The lithium-based battery of claim 36, wherein the porous carbon agglomerates are characterized by a Brunauer-Emmett-Teller (BET) surface area between approximately 50 m2 / g and 300 m2 / g measured using nitrogen gas.

42. The lithium-based battery of claim 36, wherein the porous carbon agglomerates are characterized by an electrical conductivity of between approximately 500 S / m and 20,000 S / m when compressed at a pressure of approximately 12,000 pounds per square inch (psi).

43. The lithium-based battery of claim 36, wherein the porous carbon agglomerates of porous carbon primary nanoparticles include one or more interconnected bundles of electrically conductive graphene layers.

44. The lithium-based battery of claim 43, wherein the graphene layers are arranged as one or more stacks connected to each other and defining a 3D porous scaffold structure including mesopores.

45. The lithium-based battery of claim 44, wherein the one or more stacks are disposed substantially orthogonal to each other.

46. The lithium-based battery of claim 45, wherein the graphene layers are characterized by a linear dimension of between approximately 50 nm and 200 nm.

47. The lithium-based battery of claim 43, wherein the graphene layers include one or more of single layer graphene (SLG), few layer graphene (FLG), or many layer graphene (MLG).

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