Techniques to Increase Energy Density of LFP Batteries for EVs

Lithium secondary battery with enhanced high-temperature performance through the use of a non-aqueous electrolyte containing specific additives. The battery comprises a lithium iron phosphate (LFP) positive electrode with a composite oxide active material, and a non-aqueous electrolyte that includes a lithium salt, an organic solvent, a first additive represented by the chemical formula 1, and a second additive represented by the chemical formula 2. The electrolyte contains 2% or less of the first additive and 2% or less of the second additive. This non-aqueous electrolyte provides improved thermal stability and resistance to electrode degradation compared to traditional aqueous electrolytes.

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A lithium iron phosphate positive electrode material and method that enhances electrochemical performance through a novel graphene-based interface layer. The material comprises positive electrode particles with a graphene coating layer comprising lithium carbonate and boron-doped graphene. The graphene layer is formed through a controlled dehydrogenation process in a protective atmosphere, ensuring precise control over the reaction conditions. This composite layer provides improved conductivity and interface stability compared to traditional carbon coatings, enabling enhanced fast charge/discharge performance and long cycle stability in lithium iron phosphate batteries.

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Lithium iron phosphate battery with enhanced energy density and fast charging capabilities through optimized electrode design. The battery features a positive electrode with a surface density of 23 mg/cm^2, a negative electrode with a surface density of 24 mg/cm^2, and a separator. The design incorporates a novel electrolyte composition that balances conductivity, wettability, and electrolyte density to achieve the battery's high energy density and fast charging performance.

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Nonaqueous electrolyte energy storage device with enhanced capacity retention and resistance management. The device utilizes lithium iron phosphate as the positive electrode material, with graphite and non-graphitic carbon as the negative electrode materials. The electrolyte composition is optimized to achieve high capacity retention after repeated charge-discharge cycles while maintaining low internal resistance increase rates. The electrolyte contains lithium hexafluorophosphate at concentrations of 0.7 mol/dm3 or less, with specific ratios of LiFSI to LiPF6 ranging from 50:50 to 99:1.

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A hybrid lithium-sodium ion battery combining lithium iron phosphate (LiFePO4) cathodes with iron-based polyanion cathodes. The battery features a positive electrode comprising LiFePO4, with one or more iron-based polyanion cathodes, and a conductive additive. The cathode material is optimized for conductivity while maintaining high energy density and power density. The battery achieves superior performance through the synergistic effect of both lithium iron phosphate and iron-based polyanion cathodes, with the conductive additive enhancing conductivity.

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Lithium secondary battery with improved high-temperature performance through the use of a non-aqueous electrolyte containing specific additives. The battery features a lithium iron phosphate-based positive electrode and a non-aqueous electrolyte that combines lithium salts with organic solvents and specific additives, including cyclic carbonate-based compounds and halogen-substituted carbonate-based compounds. The electrolyte maintains its performance characteristics even when heated to elevated temperatures, while the additives enhance the battery's thermal stability and capacity retention.

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A modified lithium iron phosphate cathode material for lithium-ion batteries that enhances their performance through a novel three-dimensional carbon network structure. The material comprises a lithium iron phosphate cathode with a 1-5% carbon content, where the carbon network is formed through a process that integrates 3D network precursors with lithium iron phosphate precursors. This structure enables the material to achieve improved electronic conductivity while maintaining its unique olivine-type iron phosphate structure, thereby enhancing the overall performance of lithium-ion batteries.

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Graphene-encapsulated lithium iron phosphate (LiFePO4) composite material for lithium-ion batteries, prepared through a novel solvothermal synthesis method. The synthesis process involves the controlled nucleation of graphene onto iron source particles, followed by reaction with lithium and phosphorus sources under high-temperature solvothermal conditions. The graphene serves as a nucleating agent, facilitating the formation of the LiFePO4 composite through controlled graphene-iron interactions.

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Positive electrode for lithium secondary batteries with enhanced stability against overcharge-induced gas generation and thermal runaway. The electrode features a double-layer structure comprising a first positive electrode active material layer on the collector and a second positive electrode active material layer on the first layer. The second layer incorporates lithium carbonate or lithium oxalate, which generates gas during overcharge. The electrode's design prevents the formation of a gas-filled path through the double-layer structure, thereby preventing thermal runaway and enabling reliable operation at high charge levels.

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A polymer lithium-ion battery negative electrode with improved energy density and fast charging capabilities. The battery features a novel negative electrode structure where the active material layers are selectively coated with different lithium intercalation potentials in the thickness direction. This enables optimized lithium insertion during both charging and discharging, achieving both high energy density and fast charging. The active material layer with the higher lithium insertion potential is positioned near the cathode, while the lower-intercalation potential layer is positioned near the anode.

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A lithium-ion battery cathode material that enables high-capacity batteries with improved safety and performance characteristics. The material, comprising single-crystal-like Li2FeO2 particles with a surface finish, achieves enhanced stability through the controlled oxidation of iron during high-temperature reactions. This prevents unwanted iron aggregation and maintains consistent particle size, enabling uniform current distribution and preventing thermal runaway. The material is prepared through a controlled ball milling process, resulting in a high-purity material suitable for mass production.

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Lithium iron phosphate battery with improved performance and safety characteristics through a multi-pole structure that enhances current density, reduces thermal management issues, and prevents electrolyte degradation. The battery cell incorporates a multi-pole design that increases the current conduction area while maintaining thermal stability, preventing hot pressing-related issues and side reactions. The cell architecture also features a diaphragm made of a PE-wet-coated ceramic material and a carbon-coated aluminum foil positive electrode current collector. The battery achieves higher performance and safety through these innovative structural elements.

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Lithium iron phosphate (LiFePO4) cathode material with improved conductivity and operating voltage range through controlled doping of iron and manganese sites. The material, synthesized through a novel milling process combining In2O3, Fe2O3, MnO2, and P source dispersion with ball milling, pre-sintering, and cooling, achieves consistent doping uniformity and stable performance while maintaining the material's inherent electrochemical properties.

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Lithium iron phosphate power battery that maintains charge-discharge performance at low temperatures and cycles well. The battery incorporates a positive electrode with a graphene coating on lithium iron phosphate particles, and a negative electrode comprising natural graphite and modified graphite. The graphene coating enhances lithium ion conductivity and diffusion, while the graphite components maintain high capacity. The battery achieves excellent low-temperature performance and cycle life through the optimized electrode structure, enabling continuous use of electric vehicles at temperatures below 25°C.

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Negative electrode for lithium-ion batteries with reduced surface deformation during lithiation. The electrode comprises a current collector, a first negative electrode active material layer, and a second negative electrode active material layer. The first active material layer contains a carbon-based material and a material with high capacity. The second active material layer has a uniform particle size distribution of 0.1-10 μm. This composition enables the electrode to maintain its structural integrity during lithiation without surface deformation, resulting in improved battery performance and reduced material waste.

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A method for preparing a reduced graphene oxide/carbon coating/lithium iron phosphate composite material that addresses the issues of uneven graphene dispersion and agglomeration in conventional composite formulations. The method involves a controlled reduction of graphene oxide to form a uniform dispersion of graphene particles in a carbon matrix, followed by the deposition of lithium iron phosphate onto the graphene-C composite. The graphene-C composite is prepared through a sequential process involving graphite oxide smelting, dispersion, and carbonization, followed by the deposition of lithium iron phosphate onto the carbon surface. This approach enables the creation of a uniform, graphene-C composite with controlled graphene dispersion and reduced agglomeration, resulting in improved performance of lithium iron phosphate cathode materials in lithium-ion batteries.

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Lithium iron phosphate-graphene in-situ composite material for high-performance lithium-ion batteries, enabling enhanced electrochemical performance through synergistic enhancement of conductivity and capacity. The composite material comprises lithium iron phosphate cathode material coated with graphene, with specific improvements in conductivity and capacity. The graphene enhances the material's electrical conductivity, while the lithium iron phosphate maintains its electrochemical stability. The composite material demonstrates superior performance compared to conventional lithium iron phosphate cathodes, with enhanced capacity retention and rate capability.

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A multilayer graphene/lithium iron phosphate intercalation composite material for lithium-ion batteries, achieved through a novel supercritical dimethylformamide-based graphene synthesis process. The composite material comprises a multilayer graphene electrode with a high capacity density of 131.5 mAh/g at an initial state charge of 3.5 mAh/g, and maintains 75.5% capacity retention upon repeated charge cycles. The process involves precise control of graphene synthesis conditions, including precise control of the graphite-to-graphene ratio and supercritical dimethylformamide concentration. This approach enables the creation of high-performance lithium iron phosphate intercalation electrodes with superior rate capability compared to conventional synthesis methods.

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Lithium iron phosphate battery with enhanced low-temperature performance and higher energy density. The battery features a specially designed separator that improves lithium ion diffusion at low temperatures, while maintaining the battery's structural integrity. The separator is integrated into the battery cell design, with the positive plate, separator, and negative plate forming a single unit. This configuration enables the battery to maintain its performance characteristics even at extremely low temperatures, making it suitable for electric vehicles operating in cold climates.

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Lithium iron phosphate lithium-ion battery with improved performance characteristics. The battery comprises a positive electrode comprising a positive electrode current collector and a positive electrode material, and a negative electrode comprising a negative electrode current collector and a negative electrode material. The positive electrode material includes 93-95 parts of lithium iron phosphate, 3-5 parts of a positive electrode conductive agent, 2-3 parts of a positive electrode binder, and 5-25 parts of a solvent.

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