Hard Carbon for EV Battery Construction

Carbon-coated hardly graphitizable carbon for high performance lithium-ion batteries. The carbon coating layer has an average thickness of 4-30 nm and improves battery performance compared to uncoated graphite or thicker carbon coatings. The coating thickness provides both high discharge capacity and initial efficiency. The coating promotes electrolyte stability, prevents particle deactivation, and enhances conductivity. The coated carbon has specific structural features like high sp2 carbon orientation and spacing.

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Non-graphitizable carbonaceous material for fully charged lithium-ion batteries with high charge/discharge efficiency and capacity. The material has an oxygen content of 0.25% mass or less. It enables high charge/discharge performance and capacity in lithium-ion batteries that are fully charged compared to traditional graphitizable carbon anodes. The low oxygen content prevents overcharging issues. The material is made by acid treating a plant-derived carbon precursor followed by firing in an inert gas at 1100-1400°C.

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Electrochemical device with improved energy density and reduced lithium precipitation in lithium-ion batteries using a specific range of ratios for hard carbon content and capacity balance. The hard carbon used as the negative electrode active material has a molar H/C ratio of 0.05-0.18. The capacity balance between negative and positive electrodes is 0.95-1.05. This range of ratios improves ion transmission speed, energy density, and prevents lithium segregation.

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Fast-charging lithium battery negative electrode material that combines the high capacity of graphite with the fast charging capability of hard carbon. The material is prepared by melting a resin and asphalt mixture, pre-carbonizing it, grinding it to a specific size range, and then graphitizing. The resulting material has high capacity density and can charge at 10C rates.

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Anode material for lithium-ion batteries with improved cycling performance by using a porous carbon core with optimized pore structures. The core has micropores (<2 nm) to accommodate expansion of the active material without stress concentration, and larger pores (>2 nm) filled with the active material to prevent electrolyte penetration. A coating layer on the surface further reduces electrolyte access and improves cycling stability. The core and coating are prepared by mixing the components under vacuum to enable filling of the larger pores.

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High-performance silicon-carbon anode material for lithium-ion batteries with improved capacity, cycle life, and expansion. The material has a unique structure where silicon particles are dispersed and embedded in the pores of a carbon matrix. This prevents segregation and improves capacity compared to surface coating methods. The carbon matrix is made by polymerizing active monomers to form a precursor with rich pore structure. Secondary activation enlarges the pores further. Silicon particles are then deposited inside. Coatings on the carbon or silicon further enhance properties.

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Graphitized carbon material with controlled graphitization for metallic lithium batteries that enables uniform and stable lithium plating without dendrite growth. The graphitization level is increased by infiltrating metal elements into the carbon material. This is done by soaking the carbon in a solution containing the metal elements for several hours. The metal-infused carbon is then dried and used as the negative electrode in lithium batteries. The metal-infused carbon provides a high graphitization level that improves conductivity and stability compared to unmodified carbon. During battery cycling, lithium ions embed into the carbon layer to form LiC6, which induces uniform lithium plating and prevents dendrite growth.

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Nonaqueous electrolyte secondary battery with improved cycle life and energy density by using non-graphitizable carbon in the negative electrode. The carbon expands and contracts less during charging/discharging compared to graphite, preventing electrode structure deterioration. However, keeping the capacity ratio of non-graphitizable carbon to negative electrode capacity between 5-65% balances benefits like lower resistance and overvoltage against issues like increased initial resistance and lower energy density from high carbon levels.

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High-volume performance lithium-ion battery with improved energy density by using a collapsed carbon nanocage as the negative electrode. The collapsed carbon nanocages have high density due to internal densification forces that order the nanoparticles and eliminate excess macropores. This allows higher packing density compared to porous nanocarbons. The collapsed carbon nanocages also have micropores and surface defects for better lithium storage. The collapsed carbon nanocage negative electrode in a lithium-ion battery shows improved cycle life and capacity retention compared to regular graphite anodes.

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An anode material for lithium-ion batteries with improved cycle stability and reduced expansion during charging and discharging. The anode material has a porosity of 10% or less and a target region ratio C of 15% or greater. It is prepared by mixing active material, carbon source, and solvent, followed by heat treatment and densification to form an aggregate with dispersed active particles. Additives like metal oxide, conductivity enhancer, and coupling agent can be added during mixing. Carbon coating is also done after densification. The aggregate structure with low porosity and dispersed active particles inhibits volume expansion during lithium ion intercalation/deintercalation.

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Composite negative electrode material for lithium-ion batteries with improved energy density, rate performance, and cycle life. The composite material has a core-shell structure where the core is a carbon nanotube/graphite composite and the shell is made of hard carbon. This design provides high ionic and electronic conductivity from the nanotube/graphite core, and the hard carbon shell further improves rate performance and structural stability. By optimizing the core-shell composition, it allows lithium-ion batteries with higher energy density, better rate performance, and cycle life compared to conventional graphite anodes.

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Negative electrode material for lithium-ion batteries with improved first Coulombic efficiency and cycle life. The material is hard carbon with a unique multi-level pore structure. The core has micropores (2nm) and the surface has macropores (55nm). This reduces the specific surface area compared to conventional hard carbon to lower water/oxygen absorption. It also prevents pore collapse during cycling. The micropores store lithium and the macropores provide high-rate capability. The pore ratios are micropores:mesopores:macropores = 50%:50%. This reduces water ingress while maintaining lithium storage capacity. The hard carbon can also be coated with hydrophobic molecular sieves or doped with silica to further improve water resistance.

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<|assistant| Carbon networks containing chemically interconnected carbon nanofibers as active materials in lithium or sodium battery anodes. The networks are porous and comprise carbon nanofibers with aspect ratios of at least 2. They provide high capacity, fast charging, and long cycle life for lithium and sodium batteries. The networks have intra-particle porosity, chemical interconnections between nanofibers, and nanofiber diameters smaller than graphite. This enables faster ion diffusion and electron transport compared to graphite. The networks can be used as the sole anode active material or partially replace existing anode materials.

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Porous carbon composite lithium anode for high-energy-density batteries with improved cycle life and reduced dendrite growth. The anode is made by doping in situ a porous carbon material with heteroatoms like nitrogen, oxygen, phosphorus, and sulfur. The heteroatom-doped porous carbon provides a three-dimensional structure with uniformly distributed active sites for lithium storage. The heteroatom affinity regulates lithium deposition-dissolution behavior, preventing dendrite growth. The porous structure enables uniform lithium distribution and reduces local current density. The composite anode can be prepared by mixing the doped carbon with lithium and a binder.

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High-performance sodium-ion battery anode material with improved cycling stability and rate capability compared to conventional hard carbon anodes. The anode material is a composite of small primary hard carbon particles (2-5 µm) bound together and coated with a three-dimensional composite layer of larger particles (5-12 µm). The composite structure provides improved electronic conductivity and sodium ion diffusion compared to isolated primary particles. The coating also protects the inner particles from degradation during cycling. The composite anode has higher capacity, lower voltage hysteresis, and better cycling performance compared to uncoated hard carbon anodes.

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Preparing high conductivity, high capacity anode material for lithium and sodium ion batteries by confining phosphorus in porous carbon with high electrical conductivity. The method involves creating micropores in carbon materials like hard or soft carbon using water-gas reaction, then filling the pores with phosphorus through sublimation. This confines the phosphorus within the carbon structure to mitigate volume expansion issues. The high conductivity carbon skeleton improves overall conductivity compared to traditional porous carbon.

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Preparation method for high performance hard carbon negative electrode material for sodium-ion batteries. The method involves carbonizing plant material to create a porous carbon structure. Then, organic pyrolytic carbon is embedded or attached inside or on the porous carbon. Carbon nanotubes are interspersed between the porous carbon and pyrolytic carbon. Finally, roasting is done to form parallel graphite structure with the nanotubes. This improves rate performance of the hard carbon anode material by increasing electrical conductivity and ion storage sites.

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Modified non-graphite carbon material for rechargeable batteries with improved energy density. The material is made by doping non-graphite carbon with nitrogen and/or phosphorus, then coating it with carbon. The doping improves specific capacity, reducing water absorption. The coating reduces surface area and prevents water ingress further. The modified carbon has larger interlayer spacing, better ion intercalation, and stability.

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Carbon material for high-performance lithium-ion battery anodes that provides improved charge/discharge performance and lifespan compared to conventional anode materials. The carbon material has a specific fiber content range of 0.58 to 0.78. This carbon raw material is ground and graphitized to create the anode active material. The ground carbon particles have a size range of 5 to 30 microns and the graphitized anode has a high graphitization degree, low orientation, and interplanar spacing. The anode material prepared this way has enhanced charge/discharge capacity, charge output, and discharge output compared to conventional anodes made from other carbon materials. It also has lower expansion during charging/discharging. The manufacturing method avoids the assembly process used in some anode materials to achieve similar benefits.

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A negative electrode material for lithium-ion batteries that has low average potential for lithium removal, improving battery energy density. The material is a hard carbon with a specific microporous structure. The carbon has a delithiation potential between 0.15-0.40 V vs Li/Li+ when used with a metallic lithium counter electrode. The micropores allow lithium intercalation during charging, providing reversible capacity. The optimized pore structure enables high capacity, low voltage, and good lithium ion diffusion. This carbon material is used as the negative electrode active material in lithium-ion batteries to provide higher energy density compared to conventional graphite electrodes.

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