Silicon Anodes for Improved EV Battery Performance

Pure silicon anode for lithium-ion batteries with improved capacity and stability. The anode contains tiny nuclei of specific lithium-silicon compounds with ordered structures. These compounds are formed by pre-lithiation of silicon with a protective coating and high lithium flux at specific sites. The nuclei transform during battery cycling to the final ordered structure Li4.1Si_Cmcm. This provides higher capacity compared to disordered lithium-silicon compounds. The ordered structures also suppress volume expansion and cracking of the silicon anode.

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A battery system and method for lithium-ion batteries with silicon anodes that improves capacity, energy density, and lifespan compared to conventional batteries. The key innovation is adjusting the voltage range for charging and discharging to specific limits. The maximum voltage is 4.00-4.08 V and the minimum voltage is 2.98-3.07 V. This narrower voltage range prevents excessive volume expansion/contraction of the silicon anode during cycling, reducing lifespan degradation. It also allows using higher capacity silicon anodes without sacrificing energy density.

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A silicon-containing composite for lithium battery electrodes that improves capacity, cycling life, and reduces volume expansion compared to pure silicon. The composite consists of porous silicon cores covered by graphene shells. The graphene shells prevent silicon particle separation during charging/discharging. The composite also has improved conductivity and reduces SEI layer formation compared to pure silicon. A carbon composite containing this silicon-graphene composite further improves volume energy density and suppresses volume expansion.

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Anode electrode for battery cells with improved fast charging capability using a porous silicon coating on a 3D copper mesh current collector. The silicon is deposited by physical vapor deposition (PVD) without a binder. The porous structure of the 3D copper mesh provides space for electrolyte and volume expansion of the silicon during cycling. The binder-free silicon coating reduces internal resistance for enhanced fast charging performance.

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Batteries with improved cycling stability and capacity retention for lithium-ion batteries with silicon-containing negative electrodes, achieved by using an ionogel electrolyte. The ionogel electrolyte contains a silicon-containing polymer matrix, a lithium salt, and an ionic liquid with a piperidinium cation and bis(fluorosulfonyl)imide anion. The ionogel electrolyte is infiltrated into the open pores of the silicon negative electrode during battery manufacturing. This provides a solid electrolyte interphase on the surface of the silicon electrode, improving cycling stability compared to conventional liquid electrolytes. The ionogel electrolyte also has desirable properties like high ionic conductivity, thermal stability, wide electrochemical stability window, and chemical compatibility.

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Anode material for lithium-ion batteries with improved cycling performance by mitigating volume expansion of silicon particles during charge/discharge. The anode contains a carbon matrix that disperses the silicon particles. This reduces localized stresses and cracking compared to silicon-only anodes. The carbon matrix also has controlled pore size and density to further suppress expansion and prevent electrolyte ingress. The anode composition and structure provide better cycle stability and capacity compared to conventional silicon anodes.

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A silicon-carbon mixture for lithium-ion battery negative electrodes with improved capacity retention and cycle life compared to pure silicon. The mixture contains two types of composites: a first composite with silicon and carbon, and a second composite with silicon, magnesium silicate, and carbon. The overall oxygen-to-silicon ratio is 0.06-0.90. This composition balances capacity, initial efficiency, and cycle life by mitigating volume expansion during charging/discharging. The composites have controlled internal porosity, particle sizes, and carbon coatings.

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All-conductive battery electrodes with improved cycle life and capacity retention compared to conventional lithium-ion battery electrodes. The electrodes have a coating layer with more than 50% silicon, where the silicon and other materials all have low electrical resistivity below 100 Ω-cm. The low-resistivity silicon and current collector eliminate electrical isolation during volume changes. The conductive binder pyrolyzed from the coating also provides conductivity. The all-conductive electrodes avoid capacity loss due to electrical isolation and SEI formation in silicon anodes.

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A negative electrode material for lithium-ion batteries with improved cycling performance compared to traditional graphite anodes. The material is a composite containing a porous carbon framework and a silicon-containing compound. The silicon compound is embedded within the pores of the carbon framework. This structure prevents large silicon agglomerations that can form in free silicon anodes. It also allows the silicon to expand and contract within the carbon framework without separating from the electrode.

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All-solid-state battery with improved capacity retention without the need for high pressure restraining. The battery uses a specific anode active material, silicon clathrate II type, with a surface area range of 8-17 m2/g. Applying pressure between 0-5 MPa in the layering direction helps prevent volume changes. This allows using lower pressure or no pressure compared to conventional silicon batteries. The silicon clathrate II structure reduces volume expansion during charge/discharge. The optimized surface area improves dispersion to prevent reaction nonuniformity.

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Abstract Silicon anodes, despite their high theoretical capacity, face critical challenges such as severe volume expansion (>300%), sluggish reaction kinetics, and unstable solid electrolyte interphase (SEI) formation. Herein, a novel strategy is proposed that synergistically combines supramolecular selfassembly techniques with heterojunction engineering to fabricate N, S codoped carboncoated silicon composites (Si/SiO x @C/N, S). The designed heterostructure mitigates mechanical degradation, enhances electronic conductivity, stabilizes the SEI. In situ Xray diffraction (XRD) confirms highly reversible lithiation/delithiation process, while in EIS verifies formation of stable Furthermore, density functional theory (DFT) calculations reveal between SiO carbon induces an internal electric field, significantly accelerating Li diffusion improving charge transport. Electrochemical evaluation reveals optimized MSi@SiO electrode achieves initial Coulombic efficiency 86.1% maintains capacity 1331.7 mAh g after 500 cycles at 1 A g, along excellent rate capability. ... Read More

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Silicon anode for lithium-ion batteries that can overcome the issues of volume expansion and loss of electrical contact during charge/discharge cycling. The anode structure comprises a copper current collector, an adhesion layer, and a multistratum active layer. The multistratum layer is made by alternating depositions of silicon and a metal, then rapidly annealing to form conductive metal silicide matrix enclosing amorphous/nanocrystalline silicon regions. This prevents pulverization and maintains electrical contact during volume expansion. The silicon electrode design enables high capacity silicon anodes for lithium-ion batteries without issues like pulverization and loss of contact.

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Abstract This work presents an indepth chemical and morphological investigation of the solid electrolyte interphase (SEI) formed on binderfree silicon electrodes, which include both nanowire (SiNW) amorphous (aSi) configurations, for nextgeneration lithiumion battery systems. The study focuses first five galvanostatic cycles to capture critical earlystage SEI consolidation process, essential understanding interfacial phenomena that dictate longterm performance. By employing innovative electrode fabrication techniques such as plasmaenhanced vapor deposition utilizing ionic liquid (IL)based electrolytesspecifically 1ethyl3methylimidazolium bis(fluorosulfonyl)imide (EMIFSI) formulations known their low viscosity high conductivitythis addresses challenges posed by significant volume changes inherent Sibased materials. Advanced characterization methodologies, notably OpticalPhotothermal Infrared Spectroscopy (OPTIR) Raman spectroscopy are utilized probe structural evolution with spatial resolution. multifaceted approach reveals interpl... Read More

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Lithium-ion battery anode with improved cycle life and rate performance for high capacity batteries like those used in electric vehicles. The anode has a silicon-based active material coated with a polymer or amorphous carbon layer containing carbon nanotubes (CNTs). The CNTs improve conductivity and stabilize against volume expansion of the silicon during charging/discharging. The CNTs are restrained by the polymer/carbon coating to prevent cracking and improve interfacial stability. This reduces cycle degradation compared to bare silicon anodes.

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Negative electrode material for lithium-ion batteries with improved cycling performance and capacity retention. The material is a silicon-based composite with a unique carbon coating. The silicon particles have a specific surface area oxide (SiOx) and a carbon layer covering the oxide. The carbon coating ratio and thickness are optimized to balance electron conductivity and volume expansion. The coating prevents oxide particle detachment during cycling. The carbon coating ratio is 0 < I1350/I1580 < 5 in Raman spectra, where I1350 and I1580 are peak intensities. The composite also contains graphite particles closely adjacent to the silicon particles, with >40% of the silicon particles adjacent to graphite. This reduces electron transfer resistance. The distance between silicon and graphite particles is <500 nm.

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Nanostructured silicon (Si) anodes with various dimensions (0- or 1D) are widely explored in the manufacturing of high-energy-density lithium-ion batteries (LIBs) to mitigate volume expansion during cycling. However, most them suffer from multiple issues, such as phase impurity, inhomogeneity particle size, and poor mechanical strength, resulting rate capability, cycle performance, Coulombic efficiency. In this work, a modified physical vapor deposition technique, known glancing angle (GLAD) method, is utilized produce pure Si nanospring arrays on Cu foil. The architecture, controlled dimensions, facilitates Li+ diffusion throughout amorphous offers good performance. case, electrochemical polishing foil has played pivotal role achieve very high specific capacity 2800 mAh g-1 at 300 mA capability up 4500 g-1. uniform nanosprings surface better structural robustness compared unpolished one.

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Direct coating of electrodes in silicon-dominant anode cells for lithium-ion batteries to improve cycle life and energy density. The direct coating process involves applying a precursor composite film onto the current collector and then heat treating it to convert to a pyrolyzed composite film. This converts the precursor into a stable electrode material directly on the current collector. Roll-to-roll processing allows continuous coating and heat treatment. Reducing atmosphere during heat treatment prevents SEI buildup. The direct coating reduces volume changes and maintains electrical contact during cycling, improving cycle life and capacity retention for silicon anodes.

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Abstract Fast charging (FC) capability is a frequently mentioned advantage of silicon as anode active material for lithium-ion cells. In this work, the FC multilayer pouch-cells containing 70 wt% anodes and NCA cathodes investigated over aging. Based on physicochemical-thermal model, voltage trajectories are derived based constant potential(CAP). Different safety margins used to derive different aggressive protocols. These experimentally applied cells, which aged until 70% state-of-health(SoH) using protocols in state-of-charge (SoC) windows. The resulting capacity re- tention was improved almost 850 cycles at SoH 50% SoC window. times 10 min 19 were achieved. subsequent degradation mode analysis indicated loss lithium inventory (LLI) main aging mechanism, independent LLI changed cell balancing, causing time increase by factor up 3, depending SoC. Finally, post-mortem confirmed cathode only minor modes.

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A lithium secondary battery with improved cycle life and thermal stability. The battery uses a composite anode active material with a unique structure. The anode contains composite particles made by coating a silicon material onto carbon particles with pores. The silicon coating is heated to 900-1200°C for 6-9 hours to form a coating with a very small (≤10nm) crystallite size. This prevents agglomeration/crystallization of the silicon during battery cycling and high temperatures. The coated carbon provides a matrix to confine the silicon and mitigate volume expansion. The small silicon crystallite size reduces side reactions with the electrolyte and improves battery life.

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A lithium secondary battery anode with improved cycle life for high capacity lithium batteries. The anode has two active material layers stacked on the current collector. The bottom layer has a graphite-based active material with low diffusivity. The top layer has composite particles containing silicon. The low diffusivity of the bottom layer slows lithium ion transport to prevent rapid volume expansion of the silicon in the top layer during charging. This prevents capacity fade and improves cycle life compared to using only silicon in the anode.

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