Lithium ion batteries and battery materials

Abstract

In some embodiments, a lithium-ion battery includes a first substrate, a cathode, a second substrate, an anode, and an electrolyte. The cathode is disposed on the first substrate and may contain lithium... x S y A cathode mixture of silicon-containing particles and a first particulate carbon, wherein x is from 0 to 2 and y is from 1 to 8. The anode is disposed on the second substrate and may contain a mixture of silicon-containing particles and a second particulate carbon. The electrolyte may contain a solvent and a lithium salt and is disposed between the cathode and the anode. In some embodiments, the first particulate carbon or the second particulate carbon contains a carbon aggregate comprising a plurality of carbon nanoparticles, each carbon nanoparticle comprising graphene. In some embodiments, the particulate carbon contains carbon atoms having a mesoporous structure.

Description

[0001] Related applications

[0002] This application claims the benefit of U.S. Provisional Patent Application No. 62 / 664,749, entitled “Lithium-ion Battery and Battery Materials,” filed April 30, 2018, and U.S. Patent Application No. 16 / 208,187, entitled “Lithium-ion Battery and Battery Materials,” filed December 3, 2018; these patents are incorporated herein by reference for all purposes. Background Technology

[0003] Rechargeable lithium-ion batteries are used in many applications, including automotive, mobile electronic devices, and small to large energy storage systems. Compared to conventional lithium-ion battery systems, the electrodes in novel lithium-ion batteries (such as Li / S batteries) are composed of abundant elements, and therefore promise lower costs. Additionally, Li / S batteries offer higher specific energy and energy density with similar or better performance. However, commercialization is hampered by performance limitations and practical manufacturing challenges.

[0004] One challenge that continues to hinder the practical development of Li / S batteries is the high solubility of polysulfides in conventional electrolytes. The dissolution of polysulfides leads to poor battery performance (e.g., capacity loss during repeated cycling). One mechanism by which degradation can occur is that dissolved polysulfide anions can migrate through the electrolyte and reach the anode, where they react to form insoluble products on its surface, thus impairing battery operation.

[0005] Conventional lithium-ion batteries (with conventional cathode and anode materials) have insufficient battery characteristics, such as battery life and performance. For example, sulfur-containing cathode materials tend to have low conductivity, and therefore conductive carbon is often added to the cathode to increase conductivity. In lithium-sulfur batteries where elemental lithium metal is used at the anode, the resulting batteries often exhibit poor cycle performance and stability. Summary of the Invention

[0006] In some embodiments, a lithium-ion battery includes a first substrate, a cathode, a second substrate, an anode, and an electrolyte. The cathode is disposed on the first substrate and may contain Li+. x S yThe cathode mixture and the first carbon particles, where x is from 0 to 2 and y is from 1 to 8. The anode is disposed on a second substrate and may contain an anode mixture containing silicon particles and the second carbon particles. An electrolyte is disposed between the cathode and the anode and may contain a solvent and a lithium salt. In some embodiments, the first carbon particles and / or the second carbon particles contain carbon aggregates comprising a plurality of carbon nanoparticles, each carbon nanoparticle containing graphene. The graphene in the plurality of carbon nanoparticles may contain up to 15 layers. The percentage of carbon and other elements besides hydrogen in the carbon aggregates may be greater than 99%. The median size of the carbon aggregates containing carbon nanoparticles may be from 0.1 micrometers to 50 micrometers. When measured with nitrogen as the adsorbate via the Brunauer–Emmett–Teller (BET) method, the surface area of ​​the carbon aggregates may be from 10 m². 2 / g to 300m 2 / g. When compressed, carbon aggregates can also have electrical conductivity ranging from 500 S / m to 20,000 S / m.

[0007] In some embodiments, a method of producing a lithium-ion battery includes i) assembling a cathode, ii) assembling an anode, iii) preparing an electrolyte, and iv) disposing the electrolyte between the anode and the cathode. Assembling the cathode may include providing a first substrate and disposing a cathode mixture on the first substrate. The cathode mixture may contain Li. x S y The anode comprises a first carbon particle, where x is from 0 to 2 and y is from 1 to 8. Assembling the anode may include providing a second substrate and disposing an anode mixture on the second substrate. The anode mixture may contain silicon particles and a second carbon particle. Formulating the electrolyte may include providing a solvent, providing a lithium salt, and combining the solvent and the lithium salt. In some embodiments, the first and / or second carbon particles comprise a carbon aggregate containing a plurality of carbon nanoparticles, each carbon nanoparticle containing graphene. The graphene in the plurality of carbon nanoparticles may contain up to 15 layers. The percentage of carbon to elements other than hydrogen in the carbon aggregate may be greater than 99%. The median size of the carbon aggregate containing carbon nanoparticles may be from 0.1 micrometers to 50 micrometers. When measured via the Brunol-Emmett-Taylor (BET) method with nitrogen as the adsorbate, the surface area of ​​the carbon aggregate may be from 10 m². 2 / g to 300m 2 / g. When compressed, carbon aggregates can also have electrical conductivity ranging from 500 S / m to 20,000 S / m.

[0008] In some embodiments, a lithium-ion battery includes an anode, an electroactive electrode material, and a metal current collector. The anode contains carbon particles with a mesoporous structure, and the electroactive electrode material contains silicon. In some embodiments, the lithium-ion battery includes a cathode, an electroactive electrode material, and a metal current collector. The cathode contains carbon particles with a mesoporous structure, and the electroactive electrode material contains sulfur or Li₂S. In some embodiments, the lithium-ion battery includes an anode containing the aforementioned carbon particles and a cathode containing the aforementioned carbon particles.

[0009] In some embodiments, a method of forming a lithium-ion battery electrode includes forming carbon particles in a microwave reactor and depositing the carbon particles onto a conductive current collector substrate. In some embodiments of the above method, the carbon particles comprise electroactive electrode material within a 3D mesoporous network. Attached Figure Description

[0010] Figure 1A Raman spectra of particulate carbon containing graphene are shown according to some embodiments.

[0011] Figure 1B and 1C Scanning electron microscope (SEM) images of particulate carbon containing graphene, according to some embodiments, are shown.

[0012] Figure 1D and 1E Transmission electron microscopy (TEM) images of particulate carbon containing graphene, according to some embodiments, are shown.

[0013] Figure 2A These are examples of lithium-ion batteries according to some embodiments.

[0014] Figure 2B The theoretical and actual capacities of lithium-ion battery (Li / S battery) electrodes and batteries according to some embodiments are shown.

[0015] Figure 3 Experimental examples of the capacity of a sulfur-based cathode according to some embodiments are shown.

[0016] Figure 4A and 4B Exemplary capacities of two different embodiments of silicon-based anodes according to some embodiments are shown.

[0017] Figure 5 Exemplary performance of two examples of lithium-ion batteries according to some embodiments is shown.

[0018] Figure 6 An exemplary flowchart of a method for producing lithium-ion batteries according to some embodiments is shown. Detailed Implementation

[0019] This disclosure describes a lithium-ion battery having improved cathode, anode, separator, and / or electrolyte. The electrodes (i.e., anode and cathode) may contain substrates, such as carbon substrates and / or metal foil substrates.

[0020] In some embodiments, the lithium-ion battery described herein is a Li / S battery or a Si-S-graphene battery. The cathode of the present invention may contain a substrate and a cathode mixture containing S and / or Li₂S and carbon additives (e.g., particulate carbon). In some embodiments, the cathode mixture may also contain conventional lithium-ion battery cathode materials, such as nickel-cobalt-manganese (NCM) or lithium iron phosphate (LFP). The anode of the present invention may contain a substrate and an anode mixture containing silicon and / or lithium-ion silicon particles and carbon additives (e.g., particulate carbon).

[0021] In some cases, the cathode and / or anode materials are disposed on a substrate. The substrate used for the cathode and / or anode of the present invention can be dense or porous and can contain any conductive material. The substrate can contain a single layer of conductive and non-conductive material, a multilayer of conductive and non-conductive material, an interpenetrating network of conductive and non-conductive materials, and / or a conductive porous or solid thin film or coating on a non-conductive substrate material.

[0022] The electrolyte of the lithium-ion battery of the present invention may contain one or more solvents, lithium salts, and optional redox additives. Optionally, a separator may also be used, wherein the separator is impregnated with the electrolyte and disposed between the anode and cathode. The separator may contain a polymer blend and may optionally contain incorporated non-conductive particles.

[0023] Compared to conventional Li / S batteries and lithium-ion batteries, the cathode and anode materials and structures, as well as the electrolyte composition described in this paper, improve battery performance, manufacturability, and / or stability.

[0024] For example, although not theoretically limited, the cathode structure of the lithium-ion battery of the present invention improves the lifespan of the Li / S battery by utilizing numerous small recesses to provide a high surface area compared to batteries with conventional cathodes, where polysulfides formed during charging and discharging are trapped. As a result, the migration of polysulfides to the anode is mitigated, which improves battery performance, for example, by increasing efficiency and reducing capacity loss per cycle.

[0025] In some embodiments, the carbon additives of the present invention in the cathode and / or anode exhibit improved performance compared to conventional carbon additive materials, resulting in improved battery performance (e.g., increased capacity or stability) in batteries containing electrodes using the carbon additives of the present invention. For example, the carbon additives of the present invention in the cathode and / or anode may contain particulate carbon with high compositional purity, high conductivity, and high surface area. In some embodiments, the particulate carbon has a mesoporous structure with a wide distribution of pore sizes (e.g., multimodal distribution). Without being theoretically limited, the improved carbon additives described herein are beneficial to both electrodes because they have high conductivity and high surface area to efficiently conduct electrons (e.g., with low resistive losses) to a large number of electrode / electrolyte interfaces (e.g., achieved by high surface area particulate carbon). Without being theoretically limited, the improved carbon additives described herein are also beneficial to the cathode because the pores in the mesoporous structure can trap some of the polysulfides produced, thereby preventing them from migrating through the electrolyte to the anode.

[0026] As another example, without being theoretically limited, the use of silicon in the anode of the lithium-ion battery of this invention improves battery performance and safety compared to conventional anodes made of elemental lithium. Elemental lithium is highly reactive, which poses safety concerns during battery operation and increases the cost and complexity of producing batteries using these materials as anodes. Elemental lithium electrodes in Li / S batteries also suffer from poor performance (e.g., low coulombic efficiency) and poor durability (e.g., capacity loss during cycling).

[0027] As another example, without being theoretically limited, the redox additives in the electrolyte of this invention improve the lifespan of Li / S batteries by preventing polysulfides from migrating to the anode compared to batteries with conventional electrolytes. In different embodiments, this can be achieved using different mechanisms, including promoting the reaction of polysulfides to Li₂S and sulfur and binding the polysulfides at the cathode, and by forming a more stable solid / electrolyte interface at the anode and / or cathode. In different embodiments, sulfur and / or Li₂S can be mixed with conventional cathode materials (such as NCM or LFP) to improve performance and provide an overcharge safety mechanism.

[0028] The improved cathode, anode, electrolyte, and components of each lithium-ion battery are described in detail below. The improved battery components can be used together in the same battery, or they can be combined with conventional components to produce an improved battery. For example, in an improved lithium-ion battery, an improved sulfur-based cathode can be used with a conventional anode. Alternatively, a conventional active cathode can be combined with an improved anode to produce an improved lithium-ion battery.

[0029] Cathode of lithium-ion battery

[0030] In some embodiments, the cathode of a lithium-ion (e.g., Li / S) battery comprises a substrate and a cathode mixture containing a sulfur-containing material (such as elemental S and / or Li₂S). In some embodiments, the cathode mixture contains a sulfur-containing material, one or more particulate carbon materials, and optionally may include a binder. The cathode mixture can be formed by any process. For example, the cathode mixture can be formed using a wet coating process (in which a slurry containing the cathode mixture and one or more solvents (wherein the solvents can be completely or partially removed upon drying) is deposited onto a substrate), or using a dry deposition process. An example of a dry deposition process is the use of a plasma torch, in which components (e.g., particles and / or other feedstock materials) are deposited onto a substrate using a plasma jet. In some embodiments, the cathode mixture contains a sulfur-containing material, one or more particulate carbon materials, conventional lithium-ion cathode materials (such as NCM or LFP), and optionally may include a binder.

[0031] In some embodiments, a Li / S cell with a sulfur-containing cathode is fabricated using the method described herein, the method comprising depositing a sulfur-containing cathode material within pores of a structured composite material containing a conductive material (e.g., particulate carbon).

[0032] In different embodiments, the cathode may contain S, Li₂S, Li x S y (where x = 0-2 and y = 1-8), doped S, doped Li₂S, or combinations thereof. In some embodiments, the cathode may contain S, Li₂S, Li₂S, or Li₂S in solid form or as a suspension / dissolution solution. x S y Doped S, doped Li₂S, doped Li x Composite materials of S, NCM, LFP, or combinations thereof. Doped S, doped Li₂S, or doped Li x Some examples of S include S doped with P, N, C and / or F, Li₂S or Li x S.

[0033] In some embodiments, the cathode contains Li x S y Particles (e.g., where x = 0–2 and y = 1–8) with diameters ranging from 5 nm to 100 micrometers. As used herein, Li x S y It can refer to doped or undoped Li. x S y Materials. Li x S y Some non-limiting examples of materials include S, Li₂S, doped S, doped Li₂S, or combinations thereof. In some embodiments, the particles are contained in Li₂S.x S y In a liquid-phase mixture.

[0034] In some embodiments, the cathode contains Li₂ complexed with a solvent (such as acetonitrile or any of the cathode slurry solvents described herein). x S y In some embodiments, the cathode contains Li complexed with a cathode solvent (e.g., acetonitrile) and an active redox additive (e.g., metallocene, such as ferrocene). x S y .

[0035] In some embodiments, the cathode contains polyethylene oxide / polyvinylpyrrolidone (PEO / PVP), perfluorosulfonic acid (i.e., sulfonated tetrafluoroethylene-based fluoropolymer-copolymer), polyvinylidene fluoride (PvDF), and combinations thereof.

[0036] In some embodiments, the particulate carbon in the cathode has a mesoporous structure with a broadly distributed pore size (e.g., multimodal distribution). For example, the mesoporous particulate carbon may contain multimodal pores with sizes ranging from 0.1 nm to 10 nm, from 10 nm to 100 nm, from 100 nm to 1 micrometer, and / or larger than 1 micrometer. For example, the pore structure may contain pores with a bimodal size distribution, including smaller pores (e.g., with sizes ranging from 1 nm to 4 nm) and larger pores (e.g., with sizes ranging from 30 to 50 nm). Without being theoretically limited, this bimodal distribution of pore size in mesoporous particulate carbon materials is advantageous in sulfur-containing cathodes in lithium-ion batteries because smaller pores (e.g., with sizes of 1 to 4 nm) can confine sulfur (and in some cases, control the saturation and crystallinity of sulfur and / or the sulfur compounds generated) within the cathode, and larger pores (e.g., with sizes of 30 to 50 nm, or pores larger than twice the size of solvated lithium ions) enable rapid diffusion (or mass transfer) of solvated lithium ions within the cathode.

[0037] In some embodiments, mesoporous particulate carbon and cathode active material form a metaparticle framework, wherein the cathode electroactive material (e.g., elemental sulfur) is arranged within the pores / channels of the mesoporous carbon. Without theoretical limitations, the metaparticle framework can provide low-resistance electrical contact between the insulating cathode electroactive material (e.g., elemental sulfur) and the current collector, while simultaneously providing a high surface area structure beneficial to battery capacity. Without theoretical limitations, mesoporous particulate carbon can also benefit cathode stability by trapping some of the generated polysulfides, thus preventing their migration through the electrolyte to the anode. For example, the pores in the mesoporous particulate carbon in the cathode can drive the generation of lower polysulfides (such as S and Li₂S) and prevent higher soluble polysulfides (e.g., Li₂S) that promote lithium shuttle (i.e., loss) to the anode. x S yThe formation of the particulate carbon and cathode material mixture can be adjusted during particulate carbon formation (e.g., in microwave plasma or thermal reactors). Furthermore, the solubility and crystallinity of the cathode electroactive material (e.g., elemental sulfur) associated with lithium phase formation can be confined / trapped within a microporous / mesoporous framework.

[0038] anode of lithium-ion battery

[0039] In some embodiments, the anode of a lithium-ion (e.g., Li / S) battery comprises a substrate (e.g., a metal foil substrate or a carbon substrate) and an anode mixture. In some embodiments, the anode mixture comprises a silicon material (e.g., elemental Si, LiSi, silicon-doped carbon allotropes, and Si-doped graphene-containing particulate carbon as described herein), one or more particulate carbons (e.g., graphene-containing and / or doped particulate carbon as described herein), optionally graphene oxide, optionally one or more polymer materials, and optionally one or more binders. The anode mixture can be formed by any process. For example, the anode mixture can be formed using a wet coating process (where a slurry containing the anode mixture and one or more solvents (where the solvent can be completely or partially removed upon drying) is deposited onto the substrate), or using a dry deposition process. An example of a dry deposition process is the use of a plasma torch, where components (e.g., particles and / or other feedstock materials) are deposited onto the substrate using a plasma jet. In some embodiments, the anode comprises silicon-carbon composite materials and / or silicon particles coated with carbon material. In some embodiments, the anode comprises silicon-containing core-shell particles, where silicon or carbon material is at the core. In some embodiments, the anode contains multilayer particles comprising one or more layers of silicon and one or more layers of carbon, wherein the silicon or carbon material is at the core. The core and shell and the multilayer particles can be of any shape, including those with large surface areas and / or mesoporous geometries.

[0040] In some embodiments, a Li / S cell having a silicon-containing anode is fabricated using the method described herein, the method comprising depositing silicon-containing anode material within the pores of a structured composite material containing a porous medium and a conductive material (e.g., particulate carbon).

[0041] In some embodiments, the anode contains a slurry containing silicon particles. The silicon particles may contain elemental silicon or lithium silicon compounds and their carbon complexes. Some examples of lithium silicon compounds are Li... 22 Si5, Li 22-x Si 5-y (where x = 0 - 21.9 and y = 1 - 4.9) and Li 22-x Si 5-y-z M z(Where x = 0-21.9, y = 1-4.9, z = 1-4.9, and M is S, Se, Sb, Sn, Ga, or As). In different embodiments, the silicon material can be amorphous, crystalline, semi-crystalline, nanocrystalline, or polycrystalline. The silicon particles can be nanoparticles (i.e., with a central diameter of less than 50 nm, or less than about 100 nm, or less than about 500 nm, or less than about 1 micrometer), or micrometer-sized particles having a diameter from about 500 nm to about 10 micrometers.

[0042] In some embodiments, the anode contains graphene oxide. In some embodiments, the graphene oxide supplies oxygen to the material in the anode during processing and / or operation. In other embodiments, oxygen may be supplied to the material in the anode via another method, such as by incorporating an oxygen-containing compound other than graphene oxide into the anode.

[0043] In some embodiments, the anode contains one or more polymeric materials, such as polyacrylonitrile (PAN). In some cases, the polymeric material is carbonized (e.g., by annealing in an inert gas above room temperature) to form a conductive carbon phase in the anode. In some cases, the polymeric material remains a polymer in the anode and acts as a binder for the particulate material forming the anode. For example, polythiophene, PvDF-HFP, CMC, perfluorosulfonic acid, PAN, SBR, or combinations thereof can be used as binders in the anode.

[0044] In some embodiments, the anode comprises an active anode material and particulate carbon, wherein the particulate carbon has a mesoporous structure (e.g., multimodal distribution) with a wide distribution of pore sizes. In some embodiments, the anode comprises a silicon-containing anode material within the pores of the mesoporous particulate carbon. In some embodiments, the mesoporous particulate carbon and the anode active material form a metaparticle framework, wherein the anode electroactive material (e.g., silicon) is arranged within the pores / channels of the mesoporous carbon. Without theoretical limitations, the metaparticle framework can provide low-resistance electrical contact between the anode electroactive material (e.g., elemental silicon) and the current collector while providing a high surface area structure beneficial to battery capacity. In some cases, the active silicon-containing anode material for Li / S battery anodes contains silicon-containing particles with an average particle size of less than 100 nm or less than 50 nm. Without theoretical limitations, small silicon particle sizes can be advantageous in preventing the degradation of Si-containing anode materials, which typically occurs in conventional silicon-containing anodes due to the expansion of silicon during battery operation. For example, in a Li / S cell with large silicon particles at the anode (e.g., having an average diameter greater than about 100 nm or greater than about 50 nm), the larger particles may break apart during cell operation due to the large volume expansion of silicon. Conversely, in a Li / S cell with smaller silicon particles at the anode (e.g., having an average diameter less than about 100 nm or less than about 50 nm), the particle expansion size is relatively small, which mitigates the breakage of silicon particles during cell operation.

[0045] Carbon particles for lithium-ion batteries

[0046] The lithium-ion battery of the present invention incorporates particulate carbon, which has improved performance compared to conventional carbon materials, into the cathode, anode, and / or one or both substrates. For example, particulate carbon can have high compositional purity, high conductivity, and high surface area compared to conventional carbon materials. In some embodiments, the particulate carbon also has structures that are beneficial to battery performance, such as small pore sizes and / or mesoporous structures. In some cases, mesoporous structures are characterized by structures with a wide distribution of pore sizes (e.g., pore sizes with a multimodal distribution). For example, a multimodal pore size distribution can indicate a structure with a high surface area and a large number of small pores, which is effectively connected to the substrate and / or current collector via material in a structure with a larger feature size (i.e., providing more conductive paths through the structure). Some non-limiting examples of such structures are fractal structures, dendritic structures, branching structures, and aggregate structures with interconnecting channels of different sizes (e.g., composed of generally cylindrical and / or spherical pores and / or particles).

[0047] In some embodiments, the particulate carbon materials used in the substrate, cathode, and / or anode described herein are prepared using microwave plasma reactors and methods, such as any suitable microwave reactors and / or methods described in U.S. Patent No. 9,812,295 entitled "Microwave Chemical Processing" or U.S. Patent No. 9,767,992 entitled "Microwave Chemical Processing Reactor," which are assigned to the same assignee as this application and are incorporated herein by reference as if fully set forth herein for all purposes. Additional information and embodiments of microwave plasma gas processing systems, methods, and apparatus for producing the carbon nanoparticles and aggregates described herein are also described in the relevant U.S. patents and patent applications mentioned in this disclosure.

[0048] In some embodiments, the substrate, cathode, and / or anode contain one or more particulate carbon materials. In some embodiments, the particulate carbon materials used in the lithium-ion batteries described herein are described in U.S. Patent No. 9,997,334, entitled “Seedless Particles with Carbon Allotropes,” which is assigned to the same assignee as this application and is incorporated herein by reference as if fully set forth herein for all purposes. In some embodiments, the particulate carbon materials contain graphene-based carbon materials comprising a plurality of carbon aggregates, each carbon aggregate having a plurality of carbon nanoparticles, each carbon nanoparticle comprising graphene, optionally comprising multi-walled spherical fullerenes, and optionally without seed particles (i.e., without nucleating particles). In some cases, the particulate carbon materials are also produced without the use of a catalyst. The graphene in the graphene-based carbon materials has up to 15 layers. The ratio (percentage) of carbon to elements other than hydrogen in the carbon aggregates is greater than 99%. The median size of the carbon aggregates ranges from 1 micrometer to 50 micrometers, or from 0.1 micrometers to 50 micrometers. When measured using the Brunol-Emmett-Taylor (BET) method with nitrogen as the adsorbate, the surface area of ​​the carbon aggregates is at least 10 m². 2 / g, or at least 50m 2 / g, or from 10m 2 / g to 300m 2 / g, or from 50m 2 / g to 300m 2 / g. When compressed, the carbon aggregates have an electrical conductivity greater than 500 S / m, or greater than 5000 S / m, or from 500 S / m to 20,000 S / m.

[0049] In some embodiments, the particulate carbon materials used in the substrate, cathode, and / or anode of the lithium-ion battery described herein are described in U.S. Patent No. 9,862,606 entitled “Carbon Allotropes,” which is assigned to the same assignee as this application and is incorporated herein by reference as if fully set forth herein for all purposes. In some embodiments, the particulate carbon material comprises carbon nanoparticles containing at least two linked multi-walled spherical fullerenes and a graphene layer coated with the linked multi-walled spherical fullerenes. Additionally, the carbon allotropes within the carbon nanoparticles can be well ordered. For example, the Raman spectrum of carbon nanoparticles using 532 nm incident light can have a range of approximately 1350 cm⁻¹. -1 The first Raman peak at approximately 1580cm -1 The second Raman peak is observed at a certain location, and the ratio of the intensity of the first Raman peak to the intensity of the second Raman peak ranges from 0.9 to 1.1. In some cases, the atomic ratio of graphene to multi-walled spherical fullerene in carbon nanoparticles ranges from 10% to 80%.

[0050] In some embodiments, the particulate carbon materials described herein are produced using thermal cracking apparatus and methods, such as any suitable thermal apparatus and / or methods described in U.S. Patent Application No. 9,862,602, entitled “Cracking of a Process Gas,” which is assigned to the same assignee as this application and is incorporated herein by reference as if fully set forth herein for all purposes. Additional information and embodiments of thermal cracking methods and apparatus for producing the carbon nanoparticles and aggregates described herein are also described in the relevant U.S. patents and patent applications mentioned in this disclosure.

[0051] In some embodiments, the particulate carbon used in the cathode and / or anode contains more than one type of carbon allotrope. For example, the particulate carbon may contain graphene, spherical fullerenes, carbon nanotubes, amorphous carbon, and / or other carbon allotropes. Some of these carbon allotropes are further described in the relevant U.S. patents and patent applications mentioned in this disclosure. Additionally, the different carbon allotropes in the particulate carbon may have different morphologies, such as mixtures having low and high aspect ratios, low and high surface areas, and / or mesoporous and non-mesoporous structures. Using particulate carbon with different combinations of allotropes (and in some cases, different morphologies) can enhance the electrical and mechanical properties of the battery electrodes. The mass ratio of a first carbon allotrope (e.g., having high conductivity and / or a mesoporous structure) to a second carbon allotrope (e.g., a long-chain carbon allotrope) in particulate carbon can be from 70:30 to 99:1, or from 80:20 to 90:10, or from 85:15 to 95:5, or about 85:15, or about 90:10, or about 95:5. For example, mesoporous carbon allotropes in particulate carbon can provide high surface area and / or high conductivity, and the addition of long-chain (i.e., high aspect ratio) carbon allotropes to carbon particles can improve the mechanical strength, adhesion, and / or durability of the battery, cathode, and / or anode.

[0052] In some embodiments, the particulate carbon used in the cathode and / or anode contains graphene-containing particles (e.g., having one or more of the properties described herein) and particles containing long-chain carbon allotropes (e.g., spherical fullerenes or carbon nanotube bundles connected in a linear arrangement). In some embodiments, the long-chain carbon allotropes have an aspect ratio greater than 10:1, or from 10:1 to 100:1, or about 10:1, or about 20:1, or about 50:1, or about 100:1. In some embodiments, the long-chain carbon allotropes have a width from 50 nm to 200 nm multiplied by a length up to 10 micrometers, or a width from 10 nm to 200 nm multiplied by a length from 2 micrometers to 10 micrometers. Additional particles containing long-chain carbon allotropes are described in the relevant U.S. patents and patent applications mentioned in this disclosure. The mass ratio of graphene-containing carbon allotropes to long-chain carbon allotropes in particulate carbon can be about 85:15, or about 90:10 / or about 95:5. In some embodiments, the long-chain carbon allotropes can be interlocked with other conductive (and in some cases structured or mesoporous) carbon allotropes in the particulate carbon, and can form an interlocked hybrid composite allotrope electrode that has improved mechanical properties compared to an electrode without long-chain carbon allotropes. In some embodiments, the addition of long-chain (e.g., fibrous) carbon increases conductivity in a moderate range (e.g., 1 micrometer to 10 micrometers) and the distribution of other carbon allotropes (e.g., preventing the aggregation of other carbon allotropes such as mesoporous graphene particles), while improving mechanical stability. In addition, the addition of long-chain carbon allotropes can provide additional porosity around the carbon chains, which increases ionic conductivity and mobility in the electrode. In one embodiment, these long-chain fibers achieve reduced calendering pressure during manufacturing (resulting in electrodes with increased local porosity or void fraction) compared to electrodes calendered at higher pressures without long-chain carbon, while maintaining the same (or better) mechanical stability (i.e., resistance to delamination and / or breakage). Reducing calendering pressure can be advantageous because the higher porosity obtained using lower pressures leads to increased ionic conductivity and / or mobility. Additionally, in some embodiments, the addition of long-chain carbon (e.g., fibers) can improve the elongation / strain tolerance of conventional slurry-cast electrodes. In some cases, elongation / strain tolerance (e.g., the maximum strain at failure or the amount of performance degradation at a given strain) can be increased by up to 50% compared to conventional slurry-cast electrodes. In some embodiments, adding long-chain carbon allotropes to particulate carbon in the battery electrode allows for the use of less binder or eliminates the binder altogether in the electrode.

[0053] In a non-limiting example, the mechanically robust hybrid composite electrode film may contain particulate carbon with a combination of low-density (e.g., mesoporous), hierarchical graphene-containing particles (e.g., with a particle size from 15 to 40 micrometers in diameter) and high-density particles containing long-chain linked spherical fullerenes (e.g., with dimensions of 50 to 200 nm wide by 10 micrometers long). In this example, the mass ratio of graphene carbon allotropes to long-chain allotropes is approximately 85:15. The particulate carbon in this example has high conductivity (due to the high conductivity of graphene and / or spherical fullerenes), and the long-chain allotropes provide mechanical reinforcement.

[0054] In conventional battery electrodes containing conductive and / or active material particles, binders are typically used to improve the mechanical properties of the electrode. In some embodiments, the battery electrode of the present invention is mechanically reinforced by long-chain carbon allotropes, which makes it possible to reduce or eliminate binders in the electrode. For example, an interlocking hybrid composite allotrope electrode containing mesoporous graphene and long-chain carbon allotropes can be formed to have suitable mechanical properties without the use of binders. Such binder-free electrodes can also be freestanding electrodes.

[0055] In some embodiments, interlocked hybrid composite allotropic electrodes can be formed by sintering particulate carbon after carbon and active materials have been bonded in the assembly (e.g., after slurry casting). This process can be used to consolidate and strengthen the composite electrode structure.

[0056] In a non-limiting example, a microwave plasma reactor system described in U.S. Patent No. 9,767,992, entitled "Microwave Chemical Processing Reactor," is used to generate carbon particles and aggregates containing graphite and graphene. The microwave plasma reactor in this example has a body made of stainless steel with a quartz inner wall material. However, a quartz inner wall material is not always necessary, and similar carbon materials can be produced in or near the reaction zone in reactors without quartz. In some embodiments, it is advantageous to produce particulate carbon in or near the reaction zone in a reactor without quartz because substances such as oxygen can be released from quartz and incorporated as undesirable impurities into the produced carbon material. The reaction zone volume is approximately 45 cm³. 3The precursor material is methane, which is optionally mixed with a supply gas (e.g., argon). The flow rate of methane is 1 to 20 L / min, and the flow rate of the supply gas is 0 to 70 L / min. Using those flow rates and tool geometry, the residence time of the gas in the reaction chamber is from about 0.001 s to about 2.0 s, and the carbon particle production rate is from about 0.1 g / hr to about 15 g / hr. After synthesis and collection of the aggregates, the aggregates are post-treated by annealing in an inert atmosphere at a temperature from 1000 to 2200 °C for a duration of about 60 to about 600 min.

[0057] The particles produced in this example contain carbon aggregates with multiple carbon nanoparticles, each containing graphite and graphene, and no seed particles. The particles in this example have a carbon content of approximately 99.97% or higher compared to other elements (excluding hydrogen).

[0058] Figure 1A The Raman spectrum of the particulate carbon in this example, obtained using incident light at 532 nm, is shown. Figure 1A The particles were produced using argon-containing precursors. The spectrum is at approximately 2690 cm⁻¹. -1 It has a 2D mode peak 110 at approximately 1580 cm⁻¹. -1 It has a G mode peak at 120 and at approximately 1350 cm⁻¹ -1 It has a D-mode peak at 130 and a 2D / G intensity ratio greater than 0.5. Figure 1A The 2D / G intensity ratio of the particles produced is approximately 0.7.

[0059] In this example, the aggregate size has a median of approximately 11.2 micrometers immediately after synthesis and approximately 11.6 micrometers after annealing. The size distribution of the aggregates immediately after synthesis has a 10% percentage of approximately 2.7 micrometers and a 90% percentage of approximately 18.3 micrometers. The size distribution of the annealed aggregates has a 10% percentage of approximately 4.2 micrometers and a 90% percentage of approximately 25.5 micrometers.

[0060] The conductivity was measured after the aggregates were compressed into spheres. The material immediately after synthesis (i.e., before annealing) exhibited a conductivity of 800 S / m when compressed at 2000 psi and 1200 S / m when compressed at 12,000 psi. The annealed material exhibited a conductivity of 1600 S / m when compressed at 2000 psi and 3600 S / m when compressed at 12,000 psi.

[0061] Figure 1B and 1CThis example shows a SEM image of carbon aggregates of particulate carbon, which are allotropes of graphite and graphene. Figure 1D and 1E TEM images of them are shown. Layered graphene is clearly shown within the twists (folds) of carbon. The 3D structure of the carbon allotropes is also visible. The carbon allotropes in this example have a 3D structure with hierarchical mesoporous, multi-layered graphene structures having specific edge and substrate faces. In some embodiments, the ratio of the edge face to substrate face of the graphene in the particulate carbon of the present invention is about 1:10, or about 1:100, or from 1:10 to 1:100.

[0062] The surface area of ​​the aggregates in this example was measured using the nitrogen BET method and the density functional theory (DFT) method. The surface area of ​​the aggregates determined by the BET method was approximately 85.9 m². 2 / g. The surface area of ​​the aggregates, determined by the DFT method, is approximately 93.5 m² / g. 2 / g.

[0063] Compared to conventionally produced carbon materials, the carbon particles and aggregates produced in this example using a microwave plasma reactor containing graphite and graphene exhibit high purity, high conductivity, and large surface area. Additionally, these particles possess Raman characteristics indicating a high degree of order and do not contain seed particles.

[0064] In some embodiments, the particulate carbon in the cathode and / or anode contains doped carbon material (e.g., carbon doped with H, O, N, S, Li, Cl, F, Si, Se, Sb, Sn, Ga, As, and / or other metals), undoped carbon material, or a combination thereof. The doped carbon may also include matrix allotropes having carbon atoms doped (not in the matrix structure) and / or doped with other types of carbon allotropes. The doped carbon material may also be doped with functional groups, such as amine (NH3) groups. In some embodiments, the doped carbon material is formed using a dopant material, wherein the dopant material is introduced into a gaseous, liquid, or colloidal dispersion and fed into a reactor for producing the doped particulate carbon. For example, the dopant material may be combined with a hydrocarbon precursor material and cracked in a reactor (e.g., a microwave plasma reactor or a thermal reactor) to produce the doped particulate carbon.

[0065] In some embodiments, the particulate carbon in the cathode and / or anode contains nano-mixed particulate carbon. In some embodiments, the surface area, structure, and / or surface activity of the particulate carbon material of the present invention are modulated by nano-mixing carbon particles in the carbon material with particles of other materials. In some embodiments, the particles of the nano-mixed additive material can advantageously be combined with the particles of graphene-based carbon at the particle level, which is referred to herein as nano-mixing. The average diameter of the particles of the nano-mixed additive material and the graphene-based carbon material in the nano-mixed particulate carbon can be from 1 nm to 1 micrometer, or from 1 nm to 500 nm, or from 1 nm to 100 nm, or can be as small as 0.1 nm. In some embodiments, the nano-mixed additive material and the graphene-based carbon material are chemically or physically bonded together in the nano-mixed particulate carbon. In some embodiments, nano-mixing involves introducing the nano-mixed additive during particle formation (e.g., during hydrocarbon cracking processes in microwave plasma reactors or thermal reactors) such that the nano-mixed additive material is integrated into the graphene-based carbon material as the carbon material is generated, rather than combining the carbon raw material with the additive in a subsequent process as in some conventional methods. In some embodiments, the nano-mixed additive material can be introduced as a gaseous, liquid, or colloidal dispersion into a reactor for producing nano-mixed particulate carbon. As an example, silicon can be fed into the reactor along with hydrocarbon process gases (or other carbon-containing process materials, such as liquid alcohols) to produce silicon nano-mixed with graphene, graphene-based carbon materials, and / or other carbon allotropes. In other embodiments, the nano-mixed particulate carbon obtained in this embodiment may contain O, S, and Li. x S y (where x = 0 - 2 and y = 1 - 8), Si, Li 22 Si5, Li 22-x Si 5-y (where x = 0 - 21.9 and y = 1 - 4.9) and Li 22-x Si 5-y-z M z (where x = 0-21.9, y = 1-4.9, z = 1-4.9, and M is a particle of S, Se, Sb, Sn, Ga or As and / or other metals).

[0066] In some embodiments, particulate carbon for the cathode and / or anode is generated and collected without post-processing. In other embodiments, particulate carbon for the cathode and / or anode is generated and collected, and some post-processing is performed. Some examples of post-processing include machining, such as ball milling, grinding, disc milling, microfluidization, jet milling, and other techniques to reduce particle size without damaging the carbon allotropes contained therein. Some examples of post-processing include exfoliation processes, such as shear mixing, chemical etching, oxidation (e.g., Hummer process), thermal annealing, doping by adding elements during annealing (e.g., O, S, Li, Si, Se, Sb, Sn, Ga, As, and / or other metals), steaming, filtration, and freeze drying. Some examples of post-processing include sintering processes that can be carried out at high pressure and high temperature in an inert gas, such as SPS (spark plasma sintering, i.e., direct current sintering), microwave, and UV (ultraviolet). In some embodiments, multiple post-processing methods may be used together or in series. In some embodiments, post-processing will produce functionalized carbon nanoparticles or aggregates as described herein.

[0067] Substrate for lithium-ion batteries

[0068] In some cases, the cathode and / or anode materials of the present invention are arranged on a dense or porous substrate and may contain any conductive material. Some non-limiting examples of conductive materials that may be included in the substrate of the present invention are metal foils (e.g., Ti foil, Ti alloy foil, stainless steel foil, Cu foil, Cu alloy foil or other metal foils), carbon paper, metal particles, oxide particles, carbon particles, carbon foam and / or metal foam. In some embodiments, the substrate of the electrode (i.e., anode and / or cathode) of a lithium-ion (e.g., Li / S) battery contains carbon paper, carbon fibers, carbon nanofibers, carbon cloth (e.g., woven carbon fiber cloth), particulate carbon, or combinations thereof.

[0069] The substrate may contain a single layer of conductive and non-conductive material, multiple layers of conductive and non-conductive material, an interpenetrating network of conductive and non-conductive materials, and / or a conductive porous or solid thin film or coating on a non-conductive substrate material, each of which may include one or more of the conductive materials listed above. For example, the substrate may be formed from a metal foil coated with a porous layer containing a conductive carbon allotrope (e.g., graphene). Another example of a substrate material is an interpenetrating network of carbon allotropes and non-conductive polymers.

[0070] In some embodiments, the substrate may contain materials with high conductivity (e.g., greater than 500 S / m, or greater than 1000 S / m) and / or high surface area (e.g., greater than 10 μm when measured using the Brunol-Emmett-Taylor (BET) method with nitrogen as the adsorbate). 2 / g, or greater than 50m 2Carbon substrates of carbon materials with a surface area of ​​ / g.

[0071] In some embodiments, the substrate may contain carbon paper. In some embodiments, the carbon paper contains carbon fibers formed from particulate carbon (e.g., particulate carbon described herein) and a polymer base material. The carbon fibers may be formed, for example, by electrospinning. The polymer base material used for the carbon paper may be, for example, polyacrylonitrile (PAN), polyaniline (PAni), or polythiophene (PTH), and may also include copolymers such as polyethylene oxide (PEO) or polyvinyl alcohol (PVA). In some embodiments, the carbon paper may contain an active electrode material (e.g., sulfur or silicon).

[0072] In some embodiments, the substrate for the cathode and / or anode contains a mixed allotropic carbon-based material, such as a conductive carbon fiber pad, which incorporates carbon fibers into more than one carbon allotrope (e.g., partially ordered carbon and graphene, or amorphous carbon and graphene). In some embodiments, the carbon fibers of the pad comprise a matrix having a first carbon allotrope (e.g., amorphous or partially ordered carbon) and a highly ordered second carbon allotrope (e.g., graphene or fullerene). In some embodiments, the highly ordered second carbon allotrope contains a unique carbon material, such as particulate carbon materials described herein, or fullerenes and / or linked fullerenes having improved properties compared to conventional carbon materials (e.g., improved atomic order, surface area, purity, and / or conductivity). In some embodiments, the ordered or highly ordered carbon allotrope is a carbon material having a specific crystal structure (e.g., in the case of graphene, a crystal structure with hexagonally arranged carbon atoms) and a low concentration of atomic defects (e.g., measured by Raman spectroscopy).

[0073] Additional embodiments of a substrate that can be used in the battery of the present invention (including the aforementioned mixed allotrope particulate carbon film and carbon fiber mat) are described in U.S. Patent Application No. 15 / 905,157, entitled “Mixed Allotrope Particulate Carbon Films and Carbon Fiber Mats”. This patent application is assigned to the same assignee as this application and is incorporated herein by reference as if fully set forth herein for all purposes.

[0074] In some embodiments, the substrate is carbon foam or carbon paper containing additional conductive additives and / or non-conductive redox mediator additives. In some embodiments, the redox mediator additives have a binding effect and are bound to the carbon foam or carbon paper, and / or bind polysulfides to the cathode.

[0075] In some embodiments, the substrate is carbon foam or carbon paper and includes an additional metallic or non-metallic conductive substrate. In some embodiments, the carbon foam or carbon paper is bonded to or deposited on the metallic or non-metallic conductive substrate. In some embodiments, a metallic or non-metallic layer (e.g., by sputtering) is deposited onto the carbon foam or carbon paper. In various embodiments, the metallic or non-metallic substrate described above may be porous or non-porous.

[0076] In some embodiments, the substrate is a carbon foam or carbon paper comprising carbon fibers made of a polymer / carbon composite material (e.g., ordered carbon particles mixed with PAN). In some cases, the polymer / carbon composite material contains particulate carbon materials described herein, graphene, graphene oxide, carbon nanoparticles, graphite, and / or amorphous carbon. These types of carbon fibers can be formed using electrospinning or other fiber spinning processes.

[0077] Additionally, metal foams or wire meshes can be used as substrates for electrodes (i.e., anodes and cathodes) in Li / S or Li-ion batteries. Some examples of metal foams that can be used as substrates are Ni foams, Cu foams, and Al foams. Some examples of wire meshes that can be used as substrates are Ni wire meshes, Cu wire meshes, and Al wire meshes.

[0078] In some embodiments, the substrate of the present invention comprises particulate carbon having a mesoporous structure, and the active cathode or anode material is contained within the pores of the mesoporous substrate component. For similar reasons as described above, this structure can benefit battery performance, such as capacity and / or stability, by providing a high surface area, small pores, and a low-resistivity path from the current collector to the active material.

[0079] In some embodiments, the substrate contains doped particulate carbon (e.g., sulfur-doped carbon, such as sulfur-doped CNO).

[0080] Electrolyte of lithium-ion batteries

[0081] Electrolytes can contain one or more solvents, lithium salts, and optional redox additives. In some cases, one, two, three, or four solvents are used in the electrolyte. Some examples of solvents that can be used in electrolytes are non-aqueous solvents (e.g., fluorinated solvents, vinyl solvents such as fluorinated ethers, and fluorinated dioxanes). Some examples of lithium salts that can be used in electrolytes are lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethane)sulfonylimide (LiTFSI), etc. In addition to lithium-ion batteries, the electrolytes described in this section can also be used in other types of next-generation secondary batteries, including those in which Na, Mg, or K ions replace Li ions.

[0082] In some embodiments, the redox additive may include one or more metallocenes. For example, the metallocene may contain transition metals (e.g., first d-block series transition metals, second d-block series transition metals, and / or third d-block series transition metals). Some examples of transition metals that may be in the redox additive are iron, ruthenium, osmium, rhodium, rhenium, iridium, and combinations thereof. In some cases, the metallocene may contain organic ligands. In some cases, these organic ligands may be N,N' ligands substituted with electron-donating and electron-withdrawing groups. Some examples of organic ligands that may be included in the redox additive are cyclopentadienyl, pentamethylcyclopentadienyl, 2,2'-bipyridine (bpy), or combinations thereof. In different embodiments, the concentration of the redox additive in the electrolyte ranges from 5 mM to 0.5 M. Some examples of redox additives are bis(cyclopentadienyl)ruthenium, bis(pentamethylcyclopentadienyl)ruthenium(II), ruthenium(Bpy)3PF6, and bis(cyclopentadienyl)osmium.

[0083] In some embodiments, the electrolyte is immersed in a separator made of a porous carbon-based polymer material. Some non-limiting examples of polymers used in the separator are polypropylene, polyvinylidene fluoride, and polyethylene, or mixtures of said polymer materials. Alternatively, in the case of a solid separator, the separator may be a gel or a solid. In some cases, solid separators may be produced by printing. Alternatively, the separator may be a polymer pad containing perfluorosulfonic acid or other polysulfide repellents and / or binders, and include redox mediators as defined above. Polymer pad separators may be produced by techniques such as extrusion, spinning, weaving, electrospinning, or casting. The binders, repellents, and / or redox mediators in the separator (e.g., polymer pad separators) may function to retain polysulfides near the cathode surface, thereby mitigating polysulfide migration by acting as chemical repellents, charge-based repellents, or by polysulfide diffusion and / or migration away from the cathode through the separator or steric hindrance to the anode surface. Additionally, the particulate carbon described herein may be incorporated into the separator to further reduce polysulfide migration. Furthermore, the particles incorporated into the separator can be composed of various particles dispersed in the polymer separator (e.g., non-conductive oxides, doped oxides, nitrides, carbides). The particles may also include other redox agents, such as metallocenes discussed elsewhere in this disclosure. The particles incorporated into the separator can have various morphologies, including nanoparticles, nanowires, and nanorods.

[0084] Combined with conventional battery materials

[0085] In some embodiments, the cathode, anode, carbon substrate, and electrolyte described above can be used in conjunction with conventional battery components for lithium-ion batteries (e.g., Li / S or Li-ion). For example, a Li-ion battery can be constructed using the cathode described herein and conventional lithium-ion anode materials (e.g., Li, Si, graphite, C, etc.) with associated conventional manufacturing processes and materials. In another example, a Li-ion battery can be constructed using the anode described herein and conventional lithium-ion cathode materials (e.g., LCO, NCA, NMC, LFP, S, etc.) with associated conventional manufacturing processes and materials. In yet another example, a Li-ion battery can be constructed using the electrodes described herein and conventional lithium-ion electrolytes (e.g., those containing lithium salts such as LiPF6, LiTFSI, LiFSI, etc.) and solvents (e.g., ethylene carbonate (EC), dimethyl carbonate (DMC), fluoroethylene carbonate (FEC), dioxolane (DOL), dimethoxyethane (DME), dioxane (DX), acetonitrile, etc.)).

[0086] Lithium-ion battery performance

[0087] Figure 2A Examples of lithium-ion batteries 200 according to some embodiments described herein are shown. In this example, a cathode 202 is disposed on a substrate 201, and an anode 204 is disposed on a substrate 205. An electrolyte 203, optionally including a separator, is disposed between the cathode and anode electrodes to form the battery. In different embodiments, substrates 201 and 205, cathode 202, anode 204, and electrolyte 203 may contain any of the materials described above.

[0088] Figure 2B The theoretical and practical capacities of lithium-ion battery (Li / S battery) electrodes and non-limiting examples of batteries containing different anode and cathode materials are shown. Figure 2B The silicon-based anode of the present invention (Li in this example) is shown to be superior to other conventional anode compounds (Li and C6). 22-x S 5-y The prospect of using element Si to improve the anode capacity in lithium-ion batteries. Figure 2B The invention also demonstrates the potential of the sulfur cathode (in this example, element S or Li2S) of the present invention to improve the cathode capacity of lithium-ion batteries compared to conventional cathode materials (LCO and NMC). Figure 2B It also provides a comparison between using a Li2S cathode and Li2S cathode and a conventional cell with an NMC cathode and a LiC6 anode. 22-x S 5-yNon-limiting examples of full cells with elemental silicon anodes are provided, wherein the actual battery specific energy (in Wh / kg, where mass in kg refers to the mass of the entire integrated battery including the package) is increased from 160 Wh / kg to greater than 345 Wh / kg or greater than 600 Wh / kg. In some embodiments described herein, the capacity of the lithium-ion battery is greater than 300 Wh / kg, or greater than 400 Wh / kg, greater than 500 Wh / kg, or greater than 600 Wh / kg, or greater than 800 Wh / kg, or greater than 1000 Wh / kg. In some embodiments described herein, the capacity of the lithium-ion battery can be increased by 2, 3, 4, 5, or more than 5 times compared to conventional lithium-ion batteries.

[0089] Figure 3 An experimental example of the capacity of the sulfur-based cathode described herein after approximately 350 charge / discharge cycles is shown. In this example, the cathode contains Li₂S active material and particulate carbon in a 2:1 mass ratio. The anode is elemental Li, and the electrolyte is a mixture of lithium di(fluoromethane)sulfonylimide in a 1:1 volume ratio of DOL:DME solvent with a ferrocene redox mediator. The current collector for the cathode is carbon paper, and the current collector for the anode is copper foil. The particulate carbon in this example was produced using the microwave reactor described in the aforementioned U.S. patent. The y-axis of capacity curve 210 is in mAh per gram of total cathode (not per gram of sulfur). For example, the sulfur cathode shown in curve 210 has a capacity of approximately 300 mAh per gram of cathode material after approximately 300 cycles, which is approximately twice that of conventional metal oxide cathodes in lithium-ion batteries. Figure 3 The results shown indicate that in some embodiments, the capacity of the cathode of the present invention is greater than 300 mAh, or greater than 400 mAh, or greater than 500 mAh, or from 300 to 600 mAh per gram of cathode. However, the cathode processing conditions in this example were not optimized, and these results also indicate that, with further processing optimization, the capacity of the cathode of the present invention can be greater than 400 mAh, or greater than 600 mAh, or greater than 800 mAh, or greater than 1000 mAh, or from 400 mAh to 1200 mAh per gram of cathode after 100 cycles, or after 200 cycles, or after 300 cycles, or after more than 300 cycles.

[0090] In some embodiments, the cathode of the present invention has a high capacity, such as Figure 3Those shown herein maintain high capacity even at fast discharge rates. For example, the discharge rate of the sulfur cathode described herein can be about 500 mAh per gram of cathode at slow discharge rates (e.g., C / 18 and C / 10 rates, where the total capacity C is discharged in 18 and 10 hours, respectively), and can only decrease slightly to about 400 mAh per gram of cathode at rates about 10 times faster (e.g., 1C rate, where the total capacity C is discharged in 1 hour). In some embodiments, the capacity reduction of the sulfur-based cathode is from 2% to 10% between C / 10 and C / 2 rates.

[0091] Figure 4A and 4B Exemplary capacities of two different embodiments of the silicon-based anode described herein after approximately 100 to 200 charge / discharge cycles are shown in different exemplary embodiments. The capacity is... Figure 4A The anode shown in the diagram contains particulate LiSi active material and particulate carbon in a mass ratio of 60:40. The capacity is... Figure 4B The anode depicted contains 60% by mass particulate Si active material, 20% by mass PAN binder, 19% by mass S-doped particulate carbon, and 1% by mass graphene oxide. In two of these examples, the particulate carbon and S-doped particulate carbon are generated using a microwave reactor described in the aforementioned US patent. The cathode in these examples is elemental Li foil, and the electrolyte is a mixture of lithium di(fluoromethane)sulfonylimide in a 1:1 volume ratio DOL:DME solvent with a ferrocene redox mediator. In these examples, the current collector for the cathode is lithium foil, and the current collector for the anode is carbon paper. Figure 4A and 4B The y-axis of the medium capacity curve is in mAh per gram of total anode (not per gram of silicon). For example, Figure 4A The LiSi anodes, shown by curves 310 and 320, exhibit a capacity of approximately 800 mAh per gram of anode material after more than 100 cycles, which is more than twice the capacity of conventional graphite anodes in lithium-ion batteries. The Si anode capacities are shown by curves 350 and 360. These anodes exhibit capacities of approximately 750 mAh and 900 mAh per gram of anode material after more than 100 cycles, which is more than twice or approximately three times the capacity of conventional graphite anodes in lithium-ion batteries. Figure 4A and 4BThe results shown indicate that, in some embodiments, the capacity of the anode of the present invention is greater than 500 mAh per gram of anode, or greater than 750 mAh, or greater than 900 mAh, or from 500 mAh to 1100 mAh after 100 cycles. However, the anode processing conditions in this example were not optimized, and these results also indicate that, with further processing optimization, the capacity of the cathode of the present invention can be greater than 1000 mAh per gram of anode, or greater than 1500 mAh, or greater than 2000 mAh, or greater than 3000 mAh, or from 1000 mAh to 3500 mAh after 100 cycles, or after 200 cycles, or after 300 cycles, or after more than 300 cycles.

[0092] In some embodiments, the anode of the present invention has a high capacity, such as Figure 4A and 4B Those shown herein maintain high capacity even at rapid discharge rates. For example, the discharge rate of the examples of silicon-based anodes described herein is approximately one-fifth of that at a C / 10 rate (where the total capacity C is discharged at a low rate over 2 hours), compared to a C / 2 rate (where the total capacity C is discharged over 10 hours). In some embodiments, the capacity reduction of the silicon-based anode is between 2% and 10% at the C / 10 to C / 2 ratio.

[0093] Figure 5 Exemplary performance of two examples of the lithium-ion battery (i.e., battery cell) of the present invention in approximately 40 charge / discharge cycles is shown. The specific energy of battery cells 410 and 420 is plotted in Wh / kg (where mass in kg refers to the mass of the entire integrated battery including the package). Figure 5 The specific energy of a conventional lithium-ion battery (i.e., containing a metal oxide cathode and a graphite anode) is shown in 430, and twice the specific energy of a conventional lithium-ion battery is shown in 440. The battery cell in this example includes an anode containing particulate LiSi active material and PAN binder in a mass ratio of 0.75:1. The battery cell in this example includes a cathode containing Li2S active material and particulate carbon in a mass ratio of 2:1. The battery in this example also includes an electrolyte containing LiFSI and a DX:DME solvent in a 1:2 volume ratio with polysulfide additives. The current collector for the anode is copper foil, and the current collector for the cathode is aluminum foil. The battery cell in this example shows an initial specific energy from 300 Wh / kg to 350 Wh / kg, which is approximately twice the specific energy of a conventional lithium-ion battery. In some embodiments, curve 450 shows an example of the specific energy of the current battery cell. Figure 5The results shown indicate that, in some embodiments, the specific energy of the battery cell of the present invention is greater than 200 Wh / kg, or greater than 250 Wh / kg, or greater than 300 Wh / kg, or from 200 Wh / kg to 350 Wh / kg after 10, 20, 30, or 40 cycles. However, the processing conditions of the battery cell in this example were not optimized, and these results also indicate that, with further processing optimization, the specific energy of the battery cell of the present invention can be greater than 350 Wh / kg, or greater than 400 Wh / kg, or greater than 450 Wh / kg, or greater than 500 Wh / kg, or from 300 Wh / kg to 600 Wh / kg after 10, 20, 30, 40, or more than 40 cycles.

[0094] In some embodiments, the specific energy is about 500 Wh / kg, and the energy density is about 500 Wh / L (where volume in L refers to the volume of the entire battery including the package). In some embodiments, the energy density of the lithium-ion battery is greater than 300 Wh / L, or greater than 400 Wh / L, or greater than 500 Wh / L, or greater than 600 Wh / L, or greater than 800 Wh / L, or greater than 1000 Wh / L, or from 300 Wh / L to 1200 Wh / L.

[0095] Methods for producing lithium-ion batteries

[0096] Figure 6 An example of a method 600 for producing a lithium-ion battery according to some embodiments is shown. In this example, the method for producing a lithium-ion battery includes: assembling a cathode 610, assembling an anode 620, preparing an electrolyte 630, optionally providing a separator containing the electrolyte (not shown), and arranging the electrolyte and the optional separator between the anode and the cathode 640.

[0097] In some embodiments of the above method, assembling the cathode 610 includes the following steps: providing a substrate, such as carbon fiber paper or metal foil; formulating a slurry comprising S, Li2S, NCM, LFP, first particulate carbon and optional binder; and pressing the slurry into or onto the substrate.

[0098] In some embodiments of the above method, assembling the anode 620 includes the following steps: providing a substrate, such as carbon fiber paper or metal foil; formulating a slurry comprising silicon or LiSi particles, a second particulate carbon, graphene oxide (or other oxygen source), a polymer, and a first solvent; and pressing the slurry into or onto the substrate.

[0099] In some embodiments, the cathode is formed from a cathode slurry containing a sulfur-containing material (e.g., elemental S and / or Li₂S), one or more particulate carbons, optional conventional lithium-ion cathode materials, optional one or more polymer materials, optional one or more binders, and one or more solvents. Examples of solvents that may be included in the cathode slurry are acetonitrile, N-methyl-2-pyrrolidone (NMP), diethylene glycol dimethyl ether, dimethoxyethane (DME), heptane, hexane, benzene, toluene, dichloromethane, ethanol, and variants thereof. Examples of conventional lithium-ion cathode materials include NCM, LFP, lithium cobalt (LCO), and nickel cobalt aluminum (NCA).

[0100] In some embodiments, the anode is deposited from an anode slurry. In some cases, the anode slurry may be coated onto and dried (or pressed onto or pressed into) an anode substrate to form the anode. In some embodiments, the anode slurry contains a silicon material (e.g., elemental Si, LiSi, silicon-doped CNO), one or more particulate carbons, one or more solvents, optional graphene oxide, optional one or more polymer materials, and optional one or more binders. Some examples of solvents that can be used for the anode slurry are dimethylformamide (DMF), diethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether (TEGDME), polyethylene glycol dimethyl ether (PEGDME), water, N-methyl-2-pyrrolidone (NMP), variants thereof, and other solvents compatible with the silicon-based anode used.

[0101] In some cases, other solution-based methods can be used to produce cathodes. For example, Li2S active cathode materials can be dissolved in a solvent, and the solvent mixture can be coated onto a substrate, whereby Li2S can precipitate upon drying to form Li2S particles in the cathode.

[0102] In some embodiments of the above method, the preparation of electrolyte 630 includes the following steps: providing a second solvent, a lithium salt, and a metallocene-containing redox additive; and combining the second solvent, the lithium salt, and the redox additive.

[0103] In other embodiments, the reactor is used for the formation of particulate carbon, for example, by pyrolyzing gas, liquid, and / or colloidal dispersion precursors. In some cases, the reactor for producing particulate carbon is configured to deposit the resulting particles directly onto a substrate (e.g., a moving substrate constructed in the form of a drum coater). Such methods can be advantageous because slurry processes can be eliminated, which simplifies manufacturing. In some embodiments, the unique microwave plasma reactor described herein is used to produce the particulate carbon materials described herein and membranes composed of various carbon allotropes and / or many other elements and compounds, either individually or in combination.

[0104] In some embodiments, the plasma spraying method is used to produce the anode and / or cathode structures of the lithium-ion battery of the present invention.

[0105] In some embodiments, the plasma spraying method includes: supplying a plurality of input particles (e.g., particulate carbon, doped particulate carbon, or nano-hybrid particulate carbon) and generating a plurality of ionic substances from a target material (e.g., an active cathode or anode material) (wherein the ionic substances form a coating on the input particles) to form a plurality of coated particles (e.g., mesoporous particulate carbon deposited within pores of the active cathode or anode material). The plurality of coated particles are then ionized to form a plurality of ionized particles, and a plasma jet containing the plurality of ionized particles is generated. Then, in a third stage, the plurality of ionized particles are accelerated to form a plasma spray containing the ionized particles. In some embodiments, the plurality of accelerated ionized particles are then directed to a substrate and a coating is formed on the substrate.

[0106] In some embodiments, in any of the methods described above, the substrate used for the anode and / or cathode may contain carbon paper. In any of the methods described above, the carbon paper may be carbon fiber paper formed from a mixture of carbon particle material and polymer base material. Carbon fibers may be formed, for example, by electrospinning. Carbon particles may be, but are not limited to, graphene, carbon nanoparticles, and / or other carbon particles produced by thermal or microwave pyrolysis. In some embodiments, active materials—i.e., sulfur or silicon materials or composites used for the cathode or anode, respectively—may be incorporated into the carbon paper during its manufacture.

[0107] Lithium-ion batteries and battery materials containing carbon particles

[0108] Conventional lithium-ion batteries have limitations, such as low energy density and poor cycle life and / or stability. The poor performance of conventional lithium-ion batteries is partly due to the insulating properties and micromechanical and chemical instability of the electroactive materials in conventional lithium-ion batteries (e.g., when in contact with conventional electrolytes containing liquid lithium ions). One approach to addressing these limitations involves combining carbon atoms with the electroactive materials.

[0109] Therefore, the following embodiments describe lithium-ion batteries containing carbon-based particles and electroactive materials, such as silicon and sulfur having theoretical specific capacities of 4199 mAh / g and 1672 mAh / g, respectively, with the electroactive materials exhibiting higher specific capacities than conventional electroactive battery materials. As used herein, the term "carbon-based particle" refers to mesoporous carbon particles having a wide pore size distribution (e.g., multimodal distribution, or comprising pores with sizes from 0.1 nm to 10 nm and pores with sizes from 10 nm to 100 nm). Compared to conventional carbon particles, carbon-based particles can possess the improved properties described above (e.g., higher surface area and conductivity) and can be used in several components of lithium-ion batteries (e.g., anode, cathode, and current collector). In some embodiments, the carbon-based particles may also include materials other than carbon, such as electroactive materials, alkali metals, oxide materials, and / or impurities (e.g., hydrogen and small amounts (e.g., less than 1%) of other elements, such as oxygen and / or metals). Improved matched silicon / carbon anode and sulfur / carbon cathode electrodes for lithium-ion batteries are also described, wherein the matched silicon / carbon anode and sulfur / carbon cathode electrodes exhibit improved stability and / or cycle life compared to conventional lithium-ion batteries. Additionally, in some embodiments, these electrodes are fabricated into integrated all-silicon-sulfur battery cells. In some embodiments, these integrated battery cells (i.e., batteries) are pouch-type battery cells.

[0110] In some embodiments, the electrode architecture containing carbon particles is also inherently stable during lithiation / delithiation and can be reliably manufactured on a large scale.

[0111] Lithium-ion batteries with high specific capacity and stability over many cycles have numerous applications. For example, satellites and other space technologies (e.g., technologies for space-based communications) require reliable power and energy storage, and therefore, improvements in energy density and stability (i.e., safety and cycle life) are beneficial for those applications.

[0112] In some embodiments, unique mesoporous carbon atoms provide a platform / architecture for constructing rechargeable battery electrodes, with the potential for breakthrough performance gains and cost reductions compared to existing lithium-ion batteries. In some cases, the mesoporous carbon atoms can be produced using microwave reactors operating at atmospheric pressure. In some embodiments, the carbon atoms contain 3D nanostructures of varying length scales (e.g., ranging from nanometers to micrometers) or hierarchical 3D structures (e.g., fractal structures) of varying length scales (e.g., ranging from nanometers to micrometers). The carbon atoms of the present invention can improve battery performance and durability by enhancing the functionality of the core carbon framework in terms of electronic conductivity, mechanical durability, and specific capacity. Additionally, specific electroactive materials (such as S, Si, F, Al, Ge, Sn, Sb, Fe, and combinations thereof) can be (e.g., during particle fabrication or electrode fabrication) incorporated into the mesoporous structure of the carbon atoms to produce significantly greater capacity and stability (i.e., increased cycle life at greater depths of discharge). In some embodiments, mesoporous carbon particles are combined with silicon and / or sulfur electroactive materials to produce batteries with improved performance and safety metrics compared to prior art batteries. In some embodiments, batteries having the aforementioned carbon particles and / or electroactive materials have a specific capacity from 1,350 mAh / g to 1,800 mAh / g after 100,000 cycles.

[0113] In some conventional Li-ion battery designs, key electronic and ion conduction pathways and three-phase boundary sites for rapid redox reactions (with high exchange current densities) are generated by mixing carbon and active material particles (with sizes ranging from, for example, 1–3 μm) with a binder to form a slurry (e.g., N-methyl-2-pyrrolidone (NMP)-based), casting the slurry mixture onto a metal current collector (e.g., copper and aluminum for the anode and cathode, respectively), and then drying the slurry-coated current collector. In conventional batteries, the ratio of active to inactive materials is adjusted to optimize performance, and the anode / cathode electrode thickness is adjusted to optimize capacity (matching lithium utilization / availability for each electrode). Conventional liquid electrolyte chemistry has been tailored to form a “quasi-stable” solid electrolyte interface (SEI) at the surface of the active particles to reduce capacity decay and instability (and increase electrochemical window stability). However, the interface between the active particles and the liquid electrolyte is inherently unstable, and over time, these "quasi-stable" interfaces become more resistive, partly due to increased SEI growth and micromechanical fracture of the SEI and the parent active material, in the presence of volume expansion / contraction associated with lithium intercalation / reaction. Consequently, in conventional lithium-ion batteries, lithium ions are consumed by these processes and other parasitic reactions.

[0114] The batteries and battery materials disclosed herein overcome the inherent challenges and drawbacks (e.g., stability and lifetime) of conventional batteries (e.g., those with hybrid particle slurry structures). In some embodiments, the methods described herein utilize unique freshly deposited carbon nanoparticles (e.g., 3D mesoporous nanoparticle formulations with carbon-based particles) as a conductive framework for battery electrodes. In some embodiments, specific active and functionalized elements can be incorporated (e.g., doped and / or absorbed) into the engineered carbon nanoparticle nanostructures during particle reaction / particle formation processes (e.g., in a thermal or microwave reactor). In other embodiments, post-processing (such as mixing, milling, heat treatment, and / or plasma treatment) can also be used to selectively “deposit” or incorporate electroactive nanoparticles and / or polymer binders into (and around) the carbon scaffold to produce nanoparticles with a stable SEI. In some embodiments, the polymer binder serves both as a “glue” and as a layer for reversible solid-state ion transport / conduction. Reactor (and in some cases post-reactor) processing steps can be optimized to produce carbon-based particles having a 3D interconnected network of electron conduction filaments (and / or segments) surrounded by open, porous honeycomb channels filled with pre-activated graphene fingers, electroactive materials, and / or open channels for liquid ion (i.e., lithium) conduction and / or shuttle. By controlling the 3D morphology of these materials (e.g., nanoscale pore size), the solubility and crystallinity of lithium phase formation during battery operation can be optimized at local micro and mesoscales. In some embodiments, the carbon-based particle structure at fabrication stage (with or without electroactive materials) can be engineered to be controllably “in-situ” tuned or relaxed after early conditioning (lithiation / delithiation) to form a “hardened” stable architecture with reversible, high energy storage and delivery (rate) performance.

[0115] In some embodiments, the anode and / or cathode electrodes of the present invention are produced by casting an engineered carbon element slurry onto a conductive foil (such as aluminum or copper). In other embodiments, the reactor for forming the carbon elements is configured to deposit the particles directly onto a moving substrate (e.g., in a drum coater configuration), thereby eliminating the slurry process and enabling a more efficient and effective integrated electrode / current collector manufacturing process and / or design architecture. In some embodiments, a unique microwave plasma reactor (e.g., as described above) produces carbon elements and thin / thick films (e.g., composed of various carbon allotropes and many other elements and compounds, individually or in combination). By addressing many key challenges in conventional lithium-ion battery manufacturing, such as particle handling and dispersion, the proposed carbon element approach provides nanoscale engineering and manufacturing control for improved product reliability and performance (i.e., stability and energy / power density in the case of batteries).

[0116] In some embodiments, the battery contains the aforementioned carbon particles bonded to conventional battery working (active) electrodes (such as elemental lithium metal and / or conventional LiCoO2 (LCO) electrodes). In some designs, conventional materials are used as counter electrodes (e.g., as a cathode or anode containing carbon particles, or as a cathode or anode containing carbon particles).

[0117] In some embodiments, conventional battery materials may also be used in combination with the carbon elemental particles disclosed herein. For example, when conventional materials are used as antimaterials together with the modified elemental particles, they can contribute to the efficient optimization of lithium-ion shuttle performance in batteries using the disclosed carbon elemental particles (i.e., reducing loss mechanisms and optimizing reversibility).

[0118] Anode and cathode electrodes for lithium-ion batteries containing carbon particles will now be described according to some embodiments.

[0119] In some embodiments, carbon atoms are generated via a thermal reactor or a microwave reactor. Reactor conditions can be optimized to produce high-capacity carbon / lithium intercalated particles (e.g., specific capacity >350 mAh / g after 200 cycles). Some examples of inherent, freshly deposited carbon atom properties that can be adjusted by varying reactor processing conditions include (1) morphology, (2) the ratio of the base to the edge facets, (3) structure (e.g., crystallinity), (4) chemical purity, and (5) electrochemical performance (e.g., evaluated in a “2032” half-cell cell using lithium intercalation between 0-1.5 V and at rates up to 0.5 C). In some embodiments, reactor conditions are adjusted to produce carbon atoms with improved specific capacity, porosity, surface area, structure / crystallinity, purity / surface functionalization, and SEI stability compared to conventional battery materials.

[0120] Lithium loading / intercalation into carbon atoms can also be optimized for stability and reversibility (i.e., as a potential source of lithium ions for full cell configurations).

[0121] In addition to the inherent development of carbon-based particles, polymeric artificial SEIs can be incorporated into electrode materials to achieve improved stability and performance. For example, stabilized (e.g., cyclized or carbonized) polyacrylonitrile (PAN) conductive binders (which exhibit inherent conductivity and polymer elasticity) can infiltrate into the porous carbon-based structure to form an “in-situ” solid electrolyte surface layer. In some embodiments, an acrylonitrile (AN) monomer precursor solution is also used to enhance infiltration prior to the polymerization and stabilization of PAN. These artificial solid electrolyte surface layers can be deposited in situ during carbon-based particle formation in the reactor (e.g., in a multi-chamber reactor system, in a chamber downstream of the chamber where the carbon-based particles are first formed, and before the particles leave the multi-chamber reactor) or in a post-processing step after carbon-based particle formation.

[0122] Some examples of techniques that can be used to characterize current carbon-based materials (i.e., particles or deposited films) include Brunol-Emmett-Taylor (BET) measurements for surface area, scanning electron microscopy (SEM) for morphology, Raman spectroscopy for structure / crystallinity, and scanning tunneling electron microscopy (STEM / EDX) with energy-dispersive X-ray spectroscopy for elemental mapping of active components / impurities. In some embodiments, carbon-based particles with and without incorporated active components exhibit improved surface area, morphology, dispersion of incorporated active components, and / or impurity concentration compared to conventional battery materials. Carbon-based particles can also be slurry-cast onto copper foil to form particle-containing electrode layers, and these electrodes can be tested in “2032” coin cell (and cassette cell) configurations with lithium foil counter electrodes to evaluate electrode properties. For example, charge-discharge (constant current and constant potential), cyclic voltammetry, and AC impedance can be used to measure specific capacity, coulombic efficiency, redox reaction mechanisms, diffusion, and DC resistance. In some embodiments, electrodes incorporating carbon atoms with or without incorporated active components have improved specific capacity, coulombic efficiency, redox reaction mechanism, diffusion, and / or DC resistance compared to conventional battery materials.

[0123] In some embodiments, the carbon precursor particles described above comprise active (anodic) silicon. For example, the precursor carbon particles may contain discrete silicon nanoparticles or an “in-situ” formed silicon nanostructure phase. In some cases, the carbon precursor particles with active silicon may also contain one or more polymer binders for SEI control. In some cases, the carbon precursor particles with active silicon have a specific capacity of 1000 mAh / g after 200 cycles. Both elemental silicon and silicon oxide can be incorporated into the carbon precursor particles of the battery electrode. Both elemental silicon and silicon oxide have a specific capacity greater than that of carbon / graphite (e.g., 4200 mAh / g and 1600 mAh / g). One challenge in in-situ incorporation of silicon during carbon precursor particle formation (e.g., by introducing discrete nanoparticles or vapor or liquid precursors into the reactor during particle formation) is controlling the formation of an insulating phase, such as SiC, at the interface between silicon and carbon. Reactor conditions can be adjusted to prevent the formation of an insulating layer during in-situ incorporation of the active material into the carbon precursor particles. For example, the oxidation / reduction environment of the reactor (e.g., in a microwave reactor) can be controlled (e.g., by creating mild oxidizing conditions with the addition of CO2) to prevent SiC formation. Additionally, the oxidation / reduction environment of the reactor can also functionalize the carbon surface (e.g., with oxygen, sulfur, or other substances) to affect surface tension (i.e., wettability and reactivity) for subsequent post-processing / treatment steps. In some embodiments, the carbon particles described herein are prepared using microwave plasma reactors and methods, such as any suitable microwave reactor and / or method described in U.S. Patent No. 9,812,295 entitled "Microwave Chemical Processing" or U.S. Patent No. 9,767,992 entitled "Microwave Chemical Processing Reactor," which are assigned to the same assignee as this application and are incorporated herein by reference as if fully set forth herein for all purposes.

[0124] In some embodiments, silicon nanoparticles are incorporated into or dispersed together with carbon nanoparticles in one or more post-reactor processes, rather than being directly incorporated into the active material during carbon nanoparticle formation in the reactor (e.g., a microwave reactor) (e.g., in the form of discrete nanoparticles or via steam or liquid transport). An example of a post-reactor process is plasma milling. The properties of these particles and the electrode layers containing them (e.g., carbon-to-silicon ratio and distribution, other material properties, and electrical properties within the coin cell) can be evaluated as described above, and these post-reactor-treated particles can also have improved properties compared to conventional battery materials.

[0125] In some embodiments, a cathode electroactive material (e.g., elemental sulfur or lithium sulfide) is incorporated into the carbon elemental particles described above. Various methods can be used to incorporate the cathode electroactive material into the structure of the carbon elemental particles. For example, the cathode electroactive material can be incorporated directly during carbon elemental particle formation within the reactor (e.g., by introducing discrete nanoparticles or vapor or liquid precursors into the reactor during particle formation), or by a post-reactor process (e.g., via gas-phase absorption with reactants such as phenyl sulfides). In some embodiments, with appropriate optimization within the reactor, the carbon mesoporous, elemental particle framework will constrain the growth of the cathode electroactive material (e.g., elemental sulfur) within the channels and provide the necessary electrical contact to the insulating cathode electroactive material. Furthermore, the solubility and crystallinity of the cathode electroactive material associated with lithium phase formation can be confined / trapped within the microporous / mesoporous framework.

[0126] In some embodiments, the carbon atoms contain cathode-active sulfur. The properties of these sulfur-containing carbon atoms and the electrode layer containing these atoms (e.g., carbon-sulfur ratio and distribution, other material properties, and electrical properties within the coin cell) can be evaluated as described above, and these carbon-sulfur atoms can also have improved properties compared to conventional battery materials.

[0127] In addition to inherent carbon-based particles containing sulfur, techniques similar to those described above can be used to generate polymeric artificial SEIs to achieve improved stability and performance. For example, PAN conductive binders and other candidate polymers can be infiltrated into porous carbon structures to form an "in-situ" solid electrolyte surface layer, further confining sulfur redox reactions within the mesoporous carbon framework. In some embodiments, electrodes containing carbon-sulfur particles exhibit a specific capacity of >600 mAh / g after 500 cycles.

[0128] In some embodiments, the carbon atom particles are pre-lithiated (i.e., lithium is incorporated during particle formation) and then post-reactor treated with elemental sulfur to form Li₂S within constrained channels of a mesoporous structure. Some of the post-reactor processes described above in anode formation can also be used to form Li₂S in the atomized carbon particles of the cathode. The properties of these Li₂S-containing carbon atom particles and the electrode layers containing these particles (e.g., carbon-sulfur ratio and distribution, other material properties, and electrical properties within the coin cell) can be evaluated as described above, and these Li₂S-containing carbon-sulfur atom particles can also exhibit improved properties compared to conventional battery materials.

[0129] According to some embodiments, an all-lithium-ion battery can be formed from the current anode and / or cathode described above.

[0130] In some embodiments, the current anode and / or cathode described above are formed into a complete battery cell (cell) using a conventional counter electrode (if only one current electrode is used) and / or a conventional or modified electrolyte.

[0131] In some embodiments, the lithium-ion battery comprises the current anode and / or cathode described above, and a conventional electrolyte (EC / DEC) containing 1-1.2 M LiPF6 salt in a 1:1 weight ratio of ethylene carbonate and diethyl carbonate. In other embodiments, other similar conventional lithium-ion electrolytes are used. However, in other embodiments, the lithium-ion battery comprises the current anode and / or cathode described above, and a modified electrolyte. For example, the electrolyte can be modified to improve the efficiency of sulfur confinement within the mesoporous structure and the stability of the SEI at the anode. The stability of the effect of the electrolyte modification can be evaluated in a half-cell configuration before full-cell testing.

[0132] In some embodiments, the lithium-ion battery contains the current anode and / or cathode described above and is an all-C-Si-S battery cell. In some embodiments, the thickness of the current electrodes described above is optimized to produce a matched battery cell with full lithium utilization. In some embodiments, a pre-conditioned charge / discharge protocol is used to test the full battery cell. For example, a higher first-cycle charge rate can produce a porous, resistive SEI layer with minimal solvent absorption, while a lower rate promotes a denser SEI layer. In some embodiments, the pre-conditioned protocol is used to maximize initial capacity and ensure long-term stability. In some embodiments, the lithium-ion battery (full battery cell) containing the current anode and / or cathode described above has a specific capacity of >1200 mAh / g after 1000 cycles.

[0133] Embodiments of the disclosed invention have been described in detail, one or more of which are illustrated in the accompanying drawings. Each example is provided by way of explanation and not as a limitation thereof. In fact, while the specification has been described in detail with reference to specific embodiments of the invention, it should be understood that modifications, variations, and equivalents of these embodiments will readily occur to those skilled in the art upon understanding the foregoing. For example, features shown or described as part of one embodiment may be used with another embodiment to produce yet another embodiment. Therefore, this subject matter is intended to cover all such modifications and variations within the scope of the appended claims and their equivalents. These and other modifications and variations of the invention can be practiced by those skilled in the art without departing from the scope of the invention, the scope of which is more specifically set forth in the appended claims. Furthermore, those skilled in the art will understand that the foregoing description is merely illustrative and is not intended to limit the invention.

Claims

1. A lithium (Li) ion battery comprising: a cathode formed of several graphene FLG sheets defining a three-dimensional (3D) carbon-based multi-modal structure, the cathode comprising: a plurality of interconnected channels configured to provide ion transport; and a plurality of functional pores configured to retain elemental sulfur or assist in micro- confinement of polysulfides; a plurality of aggregates formed of two or more FLG sheets sintered together and configured to provide electrical conductivity between contact points of the two or more FLG sheets; and an electroactive material including any one or more of elemental sulfur or lithium sulfide (Li2S) infiltrated into any one or more of the plurality of functional pores or the plurality of interconnected channels of the 3D carbon-based multi-modal structure, wherein the plurality of functional pores have a bimodal size distribution.

2. The Li ion battery of claim 1, further comprising: a first substrate, wherein the cathode is disposed on the first substrate.

4. The Li ion battery of claim 2, further comprising: a second substrate disposed opposite the first substrate, wherein the first substrate or the second substrate comprises any one or more of a metal foil, a carbon foam, a metal foam, a carbon paper, a carbon fiber, a carbon nanofiber, a carbon cloth, or a particulate carbon.

3. The Li-ion battery of claim 1, wherein the polysulfide comprises Li x S y wherein x is from 0 to 2, and y is from 1 to 8.

5. The Li ion battery of claim 4, further comprising: an anode disposed on the second substrate, wherein the anode comprises the three- dimensional (3D) carbon-based multi-modal structure.

6. The Li ion battery of claim 5, wherein the anode further comprises a silicon- containing material including any one or more of elemental silicon or a lithium- and silicon- containing material.

7. The Li ion battery of claim 1, wherein the FLG sheets comprise up to 15 layers of graphene.

8. The Li ion battery of claim 1, wherein at least one of the aggregates comprises greater than 99% carbon.

9. The Li ion battery of claim 1, wherein a median size of each of the aggregates is in a range between 0.1 microns and 50 microns.

11. The Li ion battery of claim 1, wherein at least one of the aggregates has an electrical conductivity between 500 S / m and 20,000 S / m.

12. The Li ion battery of claim 1, wherein the cathode further comprises a binder.

10. The Li-ion battery of claim 1, wherein a median surface area of each of the aggregates is between 10 m 2 / g and 300 m 2 / g when measured via the Brunauer-Emmett-Teller (BET) method with nitrogen as the adsorbate. ​ ​

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