Silicon Anodes for Improved EV Battery Performance

Using water-soluble weak acidic resins as carbon precursors for silicon-dominant anodes in lithium-ion batteries to improve cycle life and performance of high-silicon anodes. The carbon precursor is a water-soluble polyamide-imide (PAI) resin containing acidic functional groups. It is mixed with silicon, conductive additives, and stabilizers like polyacrylic acid in an aqueous slurry to form the anode coating. The water-soluble resin allows processing the high-silicon anode slurry without needing organic solvents. The aqueous slurry is more stable and prevents particle agglomeration compared to organic solvent-based slurries. Pyrolyzing the water-soluble precursor during anode baking converts it to carbon, forming a conductive

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Negative electrode for non-aqueous electrolyte secondary batteries with improved capacity, cycle life, and electrolyte permeability. The negative electrode contains graphite, silicon, and fibrous carbon. The graphite has a moderate graphitization degree (70-80%) and internal porosity (1-5%). The silicon content is 0.1-5.0% of the total negative active material. This composition balances capacity increase, cycle stability, and electrolyte access.

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Negative electrode composition for high-capacity lithium-ion batteries that enables the use of high-capacity silicon-based active materials without capacity degradation. The composition has a silicon-based active material, a negative electrode conductive material, and a binder. The silicon-based active material has a high silicon content (70% or more) and a carbon coating. The binder is a combination of a rubber-based binder and an aqueous binder, with higher rubber binder content. This composition prevents volume expansion and gas generation issues in silicon-based electrodes by using a rubber binder for elongation and avoiding gas generation, and a carbon coating to bind silicon particles.

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A process for preparing high capacity anode materials for lithium-ion batteries that addresses the volume expansion issue of silicon anodes. The process involves depositing thin layers of electroactive material like silicon into the pores of a porous carbon matrix in multiple steps. This creates composite particles with high electroactive material content but limited continuous domains to prevent volume expansion. The discontinuation of deposition and use of modifier materials allow controlling the electroactive material domain size. The composite particles are used as anodes with improved capacity retention compared to bulk silicon anodes. The process involves depositing electroactive material in steps, discontinuing deposition, and then depositing more material to fill the pores. This creates composite particles with high electroactive material content but limited continuous domains to prevent volume expansion. The discontinuation of deposition and use of modifier materials allow controlling the electroactive material domain size. The composite particles are used

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Negative electrode for lithium secondary batteries with improved capacity and cycle life using high silicon content. The electrode structure includes a buffer layer between the silicon-based active material and the current collector. The buffer layer has a thickness range of 0.1-2 µm and contains a binder, acrylic polymer, and conductive material. The buffer prevents direct contact between lithium metal and the silicon, suppresses reactions, and regulates pre-lithiation.

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Method to improve cycle life of high-silicon content anodes in lithium-ion batteries by optimizing formation charge rate. The disclosure proposes configuring the expansion of silicon-dominant anodes during battery formation to mitigate capacity fade and cell failure. The expansion is lowered below 1.5% laterally perpendicular to the thickness by using higher charge rates during formation when the anode has >50% silicon. This reduces stresses on the cell components and prevents issues like delamination and tearing. It allows using thinner current collectors for higher expansion and thus higher volumetric capacity silicon anodes.

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Solid-state lithium-ion batteries with improved cycle life and performance by using a specific microstructure in the silicon anode. The silicon anode is a composite material with an essentially pure amorphous porous silicon film deposited on a current collector. The porous silicon has columnar structures with frustoconical shapes converging from a closed anchoring point. This microstructure reduces delamination and fracturing during cycling compared to flat silicon layers. The composite anode is used in a solid-state battery with a solid electrolyte and cathode.

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Anode active material for lithium-ion batteries with improved cycle life and capacity retention, particularly for silicon anodes. The anode active material slurry is prepared by mixing silicon particles, a first conductive material like carbon nanotubes (CNTs), and a solvent. Then, a second conductive material like VGCFs is added and the slurry is filtered to obtain the final anode slurry. The CNTs form a 3D network around some of the silicon particles to restrain volume expansion during cycling, while the VGCFs disperse the CNTs and improve conductivity. The CNTs have polar groups on their surface to bond with the silicon particles. The total surface area of the CNTs is less than 1000 times the silicon surface area to avoid agglomeration issues.

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Negative electrode material and battery design for high energy density and fast charging rechargeable lithium batteries. The negative electrode active material is a core of carbon or carbon/silicon surrounded by a shell containing Si and lithium-containing oxysilicate (LixSiOy, 1≤x≤3, 1≤y≤6). This shell provides stability and cycling performance for the silicon core during charging and discharging. The battery design uses this negative electrode, a conventional positive electrode, and electrolyte.

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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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