State-of-the-Art Silicon Anode Batteries

A method for preparing a silicon monoxide composite material with improved electrical conductivity and initial coulombic efficiency compared to pure silicon monoxide for use in lithium-ion batteries. The method involves growing carbon nanotubes directly on the surface of the silicon monoxide using an in-situ catalyst. This provides a uniform carbon coating with nanotubes and a small amount of amorphous carbon that improves electrical conductivity and reduces volume variations during charging/discharging compared to adding carbon externally.

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A positive electrode active material for lithium-ion batteries that retains its structure and capacity after repeated charge/discharge cycles. The material has a surface region with higher concentration of an additive element X compared to the interior. This reinforces the outer surface and prevents breakage of the layered structure as lithium is extracted during charging. The higher X content surface helps the material maintain its structure and capacity over cycles compared to a homogeneous composition.

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Reducing volume change of battery active materials during charging/discharging by creating a porous structure inside the material particles. The method involves preparing a LiSi precursor with a specific crystal phase, then extracting Li using a solvent to form voids in the precursor. This step creates a porous active material with reduced volume change compared to non-porous materials. The specific crystal phase is Li22Si5.

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Anode material for lithium-ion batteries that addresses the limitations of pure silicon anodes in improving battery performance. The anode is a composite made of agglomerated nanocomposites where each nanocomposite has a dendritic nanoparticle of silicon or other Group 4A element surrounded by discrete non-porous nanoparticles of the same element. The dendritic nanoparticles interconnect in the agglomerated nanocomposites to form a porous structure. This allows volume expansion of the silicon during charging without separating from the current collector. The composite anode also has improved electrical conductivity compared to pure silicon.

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Lithium battery with high energy density and improved cycle life by using a lithium-silicon composite negative electrode. The battery has a lithium-silicon composite negative electrode active material with elemental lithium and a lithium-silicon alloy. The battery also has a protective layer on the negative electrode to suppress side reactions and lithium plating. During charging, the battery is stopped at a lower cutoff voltage where no lithium is deposited on the negative electrode. This prevents dendrite formation and improves cycle life.

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Negative electrode material for lithium-ion batteries with improved cycle life and capacity retention for high capacity silicon and tin-based anodes. The material has a coating layer on the outer surface of the core silicon/tin material that contains nitrogen and carbon. The nitrogen content is 0.1-0.66% based on the total mass of the electrode. The coating layer has a nitrogen-carbon bond (-C=N-) and an infrared absorption peak at 1350-1450 cm^-1 with 90-98% transmittance. The coating improves cycle performance compared to bare silicon/tin anodes.

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A positive electrode sheet for secondary batteries with improved performance and cycle life. The sheet has a core-shell structure for the positive electrode active material. The inner core contains a doped lithium manganese phosphate with elements like Zn, Al, Si, and N. The core is coated with cladding layers of pyrophosphates, phosphates, and carbon. This core-shell design reduces manganese leaching, lattice strain, and improves cycling stability, storage, rate, and safety compared to regular lithium manganese phosphate. The core-shell structure can be used in single-layer or multi-layer positive electrode coatings on battery current collectors.

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Prismatic battery cell design to enable high-expansion anode materials like lithium metal or high-silicon anodes in prismatic battery cells. The design uses internal springs inside the cell case to mitigate overpressure issues caused by expanding anodes. The springs allow the anode electrode to expand and contract within the cell case while maintaining desired pressure ranges. This prevents excessive expansion that can damage the case or cause internal failures. The internal springs provide a buffer to keep electrode pressures within limits during cycling.

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Composite electrode for lithium-ion batteries with high capacity silicon anodes that avoids the pulverization and cycling degradation issues of bulk silicon. The composite electrode has silicon nanostructures grown directly on stainless steel substrates. The steel acts as a catalyst and seed for the silicon growth. The nanostructures densely pack on the steel to withstand volume expansion. The steel substrate also provides electrical contact. The composite electrode can deliver high silicon capacity and cycling stability for lithium-ion batteries compared to bulk silicon anodes.

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A lithium ion battery with improved rate performance using a specific electrolyte additive. The battery contains a negative electrode with silicon particles dispersed in a lithium silicate phase. The electrolyte solution has a fluorine-containing linear carboxylic acid ester. This additive prevents cracks in the lithium silicate phase during charging/discharging, reducing formation of resistance layers. The ester forms a SEI film on the silicate surface, allowing volume expansion without cracking. The SEI film has high lithium ion permeability and stability, preventing deterioration in high-rate charging. The fluorine substitution on the ester chain enhances ionic conductivity.

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A compact, high-density battery assembly for aerospace vehicles like drones and satellites that enables lightweight, powerful batteries. The assembly has multiple stacks of battery cells arranged in linear groups, connected end-to-end with foldable group connectors. This allows efficient packing of many cells in a compact linear arrangement. The groups are further connected end-to-end to form longer linear arrays. The linear arrays can be easily folded and packaged for compact shipping. The foldable group connectors also enable flexible assembly and disassembly of the linear arrays.

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Anode active material for lithium secondary batteries with improved stability and energy density compared to conventional silicon anodes. The material is a doped silicon oxide with a carbon coating on the surface. The dopant is magnesium, and the surface contains magnesium hydroxide. The key is keeping the ratio of magnesium hydroxide peak area to the total magnesium peak area below 60% when measured by XPS. This prevents gas generation during slurry preparation and ensures stable electrode manufacturing. The carbon coating improves cycle life.

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Highly reliable electrode for lithium-ion batteries with improved cycle life and reduced capacity fade compared to conventional electrodes. The electrode uses nanowires of silicon grown on a nucleus particle, surrounded by graphene sheets and polyimide film. The nanowire structure reduces expansion/contraction-induced deformation and fracture of the silicon active material compared to conventional 2D silicon sheets. The graphene prevents film formation and capacity loss. The polyimide film provides stability and prevents electrolyte reaction. This electrode design provides reliable and long-lasting lithium-ion batteries.

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Preparing amorphous silicon powder for lithium battery anodes using a low-temperature vapor phase reduction process. The amorphous silicon powder is made by reducing the oxide of silicon through a ball milling and vapor phase reduction process. The amorphous silicon powder is prepared by ball milling an amorphous silicon oxide to obtain an amorphous silicon oxide powder, then performing a low-temperature vapor phase reduction to reduce the oxide and obtain the amorphous silicon powder. The amorphous structure of the silicon powder improves battery performance by preventing cracking and volume expansion during lithium intercalation.

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Accurately assessing state-of-health (SOH) of lithium-silicon batteries that have challenges due to the unique properties of silicon anodes compared to graphite anodes. The method involves calculating SOH using an enhanced model that incorporates data beyond what is directly provided by the battery. This includes operational and manufacturing data. This improves SOH estimation for lithium-silicon batteries which have different degradation mechanisms and voltage hysteresis compared to graphite-based batteries.

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Preparing a negative electrode slurry for lithium-ion batteries with improved dispersion and slurry properties for scaling up production. The slurry is made by a two-step process. First, a dry mixture of carbon black and graphene nanoplatelets/graphite is prepared. Then, a dispersion of carbon nanotubes/nanofibers is added to the dry mixture. This two-step process helps balance slurry viscosity during scaling by utilizing the lower density graphene nanoplatelets/graphite to balance the carbon nanotubes/nanofibers. After adding part of the binder solution, the remaining binder and solvent are added to complete the slurry.

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Lithium battery with improved cycle life and storage performance at high operating voltages by using a positive electrode material with large particle size to stabilize the interface and prevent deterioration. The positive electrode active material is single crystal or single crystal-like particles with a size of 1-20 μm, preferably 3-15 μm. This large particle size reduces the specific surface area to minimize side reactions at the interface, improving cycle life and storage performance.

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Non-aqueous electrolyte secondary battery with improved performance and reliability by pre-doping the negative electrode before assembly. The pre-doping involves charging the negative electrode active material powder with lithium ions in an electrolyte before forming the battery. This reduces expansion and contraction issues during charging/discharging and prevents peeling of the active material from the current collector. The pre-doping also compensates for irreversible capacity losses in the negative electrode. The pre-doped negative electrode has a carbon-silicon ratio of 90:10 to 0:100 and a low final negative electrode potential. The electrolyte concentration in the negative electrode mixture is higher than in the overall battery electrolyte.

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Lithium-ion battery with improved cycle life and using a silicon oxide negative electrode and a fluorinated acid anhydride electrolyte additive. The silicon oxide negative electrode provides high capacity due to its large lithium intercalation, but expansion/contraction during charging/discharging degrades performance. The fluorinated acid anhydride additive in the electrolyte improves cycle life by reducing degradation of the electrolyte caused by the silicon oxide expansion/contraction. The lithium ion secondary battery with this configuration has improved cycle characteristics compared to conventional silicon oxide negative electrodes without the fluorinated acid anhydride additive.

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Estimating the state of charge (SOC) of a lithium-ion battery with mixed electrodes (like graphite and silicon) that have different charge/discharge voltage convergence behavior. The method involves estimating the open circuit voltage (OCV) using an equivalent circuit model based on electrochemistry, then estimating SOC using separate charge and discharge OCV characteristics. The key insight is to separately estimate the current through the silicon-containing portion of the electrode, which allows accounting for the different charge/discharge convergence. By accurately estimating the silicon current, it improves the overall SOC estimation accuracy for batteries with mixed electrodes.

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