General Motors Innovations in Li-ion Battery

Preparing lithiated silicon electrode materials for lithium-ion batteries using a centrifugal atomization process. The process involves forming a precursor by mixing lithium and silicon at elevated temperatures and pressures in an impingement mixer. The precursor is then centrifugally atomized to form small, spherical lithium-silicon alloy particles. This reduces lithium evaporation and gravity separation compared to melting and atomizing the lithium and silicon separately. The centrifugal atomization also forms uniform, monodisperse particles for improved battery performance.

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Low-temperature atomic layer deposition (ALD) method to form interfacial lithium fluoride layers on components of lithium-ion batteries prior to cell assembly. The ALD process involves reacting lithium hexafluoroacetylacetonate precursor with functional groups on the component surface, then introducing oxidant like water to form a single molecular layer of lithium fluoride. Steps are repeated to build up thickness. The low-temp ALD allows forming ionically conductive, electrically insulating LiF layers directly on battery components like separators and electrodes before assembly. This prevents direct lithium-electrolyte contact during cycling.

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Electrode design for high-rate lithium-ion batteries that reduces dendrite formation, improves cycle life, and allows faster charging. The electrode has a modified carbon membrane with elevated lithium nucleation sites compared to the unmodified membrane. This modified region promotes uniform lithium plating/stripping and prevents dendrites. The rest of the membrane serves as the current collector. Modifications like laser ablation, doping, or coating a lithophilic layer are used to create the modified region. This allows faster charging without sacrificing cycle life due to dendrite formation.

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Hybrid electrochemical cells that combine lithium-ion battery electrodes with capacitor electrodes to achieve higher energy density and power density compared to traditional lithium-ion batteries. The cells have hybrid electrodes with separate regions for battery materials like graphite, silicon, and lithium metal oxides, and capacitor materials like activated carbon, graphene, and lead oxide. The battery and capacitor regions are coated on opposite sides of a current collector to form a stacked electrode. This allows separate optimization of battery and capacitor properties for improved overall cell performance.

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A reference electrode assembly for secondary lithium ion batteries that can be integrated into commercial battery cells for real-time monitoring and optimization of charging and discharging. The assembly has a porous membrane with a carbon layer and a reference electrode layer deposited on one side. The carbon layer provides conductivity to an external connector tab, allowing the reference electrode potential to be measured. This enables individual electrode potentials and state of charge monitoring during cycling. The carbon layer facilitates manufacturing using printing techniques.

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Electrode fabrication process for lithium-ion batteries with high energy density and long cycle life. The process involves rolling an admixture of electroactive material, binder, and solvent into a sheet, then forming a multi-layer stack. The stack is rolled through gaps of decreasing size to form thin, dense electrode films. This multi-step rolling process compresses the material and reduces porosity. The dense films are then dried to remove solvent. The resulting electrodes have lower tap density, high discharge capacity, and improved cycle life compared to wet coated electrodes.

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Negative electrode material for lithium-ion batteries with improved cycling life and capacity retention for high-energy density applications like electric vehicles. The negative electrode uses a multilayer carbon coating on the electroactive material like silicon to prevent fracturing during cycling. The coating is formed by treating the electrode with oxygen at high temperature to form an intermediate oxide layer, followed by carbon pyrolysis. The coating has an inner amorphous carbon layer next to the oxide and an outer graphitic carbon layer. This double-layer structure provides flexibility and durability during volume expansion/contraction.

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Electrochemical devices like lithium-ion batteries that internally heat themselves using induction to improve performance in cold environments without external heating. The device has an induction coil inside the cell that receives alternating current to generate a magnetic field. This field induces eddy currents in the conductive cell components like current collectors and electrodes, generating heat. The coil can be powered by the cell itself or an external source. This in-situ heating avoids heat loss to the environment and provides uniform temperature compared to external heating methods.

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Making prelithiated negative electrodes for lithium batteries with higher capacity and cycle life by loading the electrode with excess lithium before assembly. The method involves making a precursor mixture with lithium-silicon alloy particles, carbon particles, and a polymer binder dissolved in a solvent. This mixture is applied to a current collector and dried to form the electrode layer. During drying, the polymer pyrolyzes to form a conductive carbon matrix. The prelithiated electrode has a higher initial lithium content compared to a normal electrode, reducing lithium loss during initial charging and improving cycle life.

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Creating a lithium reservoir in lithium-ion batteries to improve capacity retention by adding a lithiation additive containing lithium and metals like iron, copper, cobalt, or manganese to the positive electrode. This additive blended with the positive electroactive material helps prevent lithium loss during cycling by providing an internal lithium source. The lithiation additive forms a reservoir of lithium that can replenish the positive electrode during cycling to reduce capacity fade. It addresses the issue of lithium loss from volume-expanding negative electrodes during cycling by providing an internal source of lithium.

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Capacitor-assisted gradient electrodes for high-performance lithium-ion batteries with improved cycling and power capabilities. The electrodes have multiple layers of electroactive materials with different specific capacities, alternated with layers of capacitor materials. This graded structure absorbs regeneration currents during charging, preventing plating and enabling higher intercalation/deintercalation rates. The capacitor layers buffer the current density spikes during charging and discharging, reducing lithium plating on the active materials. The gradient electrodes can be made by coating the current collector with the electroactive materials, drying, pressing, and repeating with the capacitor materials.

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Prelithiated negative electrode material for lithium-ion batteries that improves cycle life and capacity retention compared to conventional lithium-ion batteries. The prelithiated electroactive material is made by centrifugally distributing a molten precursor containing silicon, lithium, and a small amount of additional metal. The centrifugal atomization process forms spherical particles with a composition of Li4.4xSixMy where x is a fraction between 0 and 0.85. The small amount of additional metal prevents segregation and evaporation during atomization. The prelithiated silicon particles have a size below 20 microns. This prelithiated silicon material provides higher specific capacity and reduced lithium loss compared to conventional silicon anodes.

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Making prelithiated electroactive materials for lithium-ion battery negative electrodes that can minimize capacity fade and maximize charge capacity in commercial lithium-ion batteries with long lifespans, especially for transportation applications. The method involves centrifugally atomizing a molten precursor of silicon, lithium oxide, and optionally silicon oxide to form spherical prelithiated silicon oxide particles containing both lithium silicide and lithium silicate. The particles have a diameter less than 20 micrometers. This prelithiation reduces lithium consumption during cycling compared to lithiation after cell assembly. It also prevents large volumetric expansion during cycling that can damage the electrode structure. The prelithiated particles can be used in negative electrodes for lithium-ion batteries with improved cycling performance.

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A method to form anodes for lithium-ion batteries that have solid electrolyte interfaces (SEIs) to prevent dendrite growth and improve cycle life. The anode SEI is formed separately before assembling the cell. It involves applying sequential electrolyte layers to the raw anode, drying between layers, and assembling the final anode into the cell. The SEI-forming electrolytes contain lithium salts dissolved in organic solvents. The separate SEI steps reduce dendrite growth and improve cycle stability compared to in-cell SEI formation.

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Electrolyte system for lithium-ion batteries that improves performance, especially for high-voltage applications like lithium-sulfur batteries. The electrolyte contains an aliphatic fluorinated disulfonimide lithium salt like lithium bis(fluorosulfonyl)imide in a mixture of organic solvents. The solvent mixture includes a first solvent like ether or carbonate, and a second solvent like fluorinated ether. The molar ratios of the solvents can be tailored. This electrolyte system provides good electrolyte stability, ionic conductivity, and battery cycling at high voltages.

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Protective coating for metal anodes in lithium-ion and sodium-ion batteries that prevents mossy SEI formation, dendrite growth, and impedance increases during cycling. The coating is a mesoporous film made of ceramic oxides like Li2SiO3, LiAlO2, Li2O-Al2O3-SiO2, etc. The mesoporous structure traps protons from HF without forming releasable water molecules. This scavenges HF without generating more HF. The coating also blocks electron transfer and regulates ion distribution. It improves cycle life, efficiency, and capacity retention compared to bare metal anodes.

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High-performance lithium-ion battery negative electrodes with improved cycling stability and capacity retention, especially for vehicle applications. The negative electrodes contain silicon particles with an average diameter of at least 1 micron, graphene nanoplatelets as the conductive material, and a polyimide-based binder. The larger silicon particle size reduces volumetric expansion during lithiation/delithiation compared to smaller particles. The graphene nanoplatelets provide electrical conductivity. The polyimide binder promotes mechanical robustness. Heat treatments of the electrode at temperatures less than 400°C prevent excessive expansion.

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Hybrid lithium-ion battery that can successfully use two different electrode active material chemistries regardless of voltage mismatch, especially for transportation applications. The battery has positive and negative electrodes with distinct electroactive materials, but a voltage modification component like a diode between them to compensate for voltage mismatch during charging/discharging. This allows using high energy density and high power density materials together.

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Electrolyte composition for lithium-ion batteries with extended cycle life by stabilizing anode, cathode, and lithium salt against degradation. The electrolyte contains propylene carbonate solvent, a lithium salt, and three additives: vinylene carbonate, lithium difluorophosphate, and prop-1-ene-1,3-sultone. The additives stabilize the anode, cathode, and lithium salt respectively. This prevents graphite anode exfoliation and lithium salt decomposition during cycling.

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Non-aqueous, aprotic liquid electrolytes for lithium ion batteries that have improved low temperature operation, oxidative stability, and thermodynamic stability compared to conventional electrolytes. The electrolytes contain a combination of cyclic and acyclic carbonate solvents along with a specific acyclic fluorinated ether solvent. The fluorinated ether improves low temperature performance by avoiding solvent cointercalation in graphite-based negative electrodes. It also improves oxidative stability by inhibiting solvent oxidation during high voltage operation. Additionally, the fluorinated ether raises the electrolyte's flash point.

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Electrolyte composition and positive electrode material for high-performance lithium-ion batteries with improved cycle life and fast charging capability, particularly for batteries with phospho-olivine positive electrodes like LMFP. The electrolyte contains a ternary salt mix of LiPF6, LiFSI, and LiClO4 in a solvent blend of fluorinated cyclic carbonate and linear carbonate. The optimized salt ratio and solvent blend provide stability against lithium metal anodes, reduced resistance, and improved efficiency compared to LiPF6-only electrolytes.

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Electrochemical cell design for lithium-ion batteries with improved capacity and cycle life. The cell uses an over-lithiated positive electrode material like Li1.05Mn2O4 or LiMn1.5O4 instead of the standard LiMn2O4. This compensates for lithium loss during the first cycle of silicon anodes by providing excess lithium in the cathode. The silicon anode has high lithium retention efficiency. The over-lithiation prevents capacity fade due to lithium depletion in the cathode. The cell also uses an electrolyte, separator, and current collector as normal. The over-lithiated cathode and high-efficiency anode together balance lithium transfer to extend cycle life compared to conventional cells with silicon anodes.

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High-performance lithium ion batteries with improved electrodes and methods for making them. The batteries have prelithiated silicon-containing negative electrodes that contain lithium silicide. The lithium content is determined based on factors like cycle efficiency, state of charge, and capacity ratio. This compensates for initial lithium loss during formation and minimizes capacity fade. The prelithiation maximizes specific power and energy while allowing operation at lower voltages.

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High-nickel-content positive electrodes for lithium-ion batteries that have reduced gelation and improved uniformity compared to conventional high-nickel electrodes. The electrodes contain a blended electroactive material with a first nickel-rich cathode like NMC811 (Ni>0.6) and a second phospho-olivine compound (e.g., LiFePO4). The phospho-olivine compound lowers the pH of the slurry during electrode preparation, preventing gelation and enabling uniform coating compared to high-nickel slurries. This allows fabricating high-nickel-content electrodes with improved energy density and cycling performance compared to conventional high-nickel electrodes.

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Method to make prelithiated silicon-based electrode material for lithium-ion batteries that reduces volume expansion and cracking during cycling compared to unlithiated silicon. The method involves briquetting a mixture of lithium and silicon particles at low temperature and pressure. This forms a precursor briquette with the lithium and silicon particles distributed in a matrix. The briquetting prevents separation and evaporation of molten lithium and silicon during melting. The precursor briquette is then melted to form homogeneous lithium-silicon alloy electrode material with improved cycling performance.

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Lithium-ion battery cathodes with channeled lithium metal oxide (LMO) active materials to improve durability, reduce delamination, and enhance ionic conductivity. The channeled cathodes have LMO active material applied to both sides of the current collector. Channels extend across the LMO layers, spaced apart by a few millimeters. The channels are shallow, extending 25-90% of the LMO thickness. This allows flexible roll-to-roll manufacturing without cracking. The channels provide faster ion diffusion through the electrolyte compared to solid LMO, reducing cell resistance.

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Micro-sized secondary particles for solid-state lithium-ion batteries with enhanced ionic conductivity. The particles have a core of electrode material surrounded by a solid-state electrolyte. The electrode material can be a cathode or anode active material. The solid-state electrolyte penetrates the electrode material, improving ionic conductivity compared to traditional micro-sized particles with just a solid electrolyte coating. This allows solid-state batteries to have higher power, energy density, and thermal tolerance.

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A continuous heat treatment process for fabricating electrodes with improved capacity and cycling performance for lithium-ion batteries. The process involves transferring the electrode workpiece between two spools in a sealed chamber while controlling the temperature in the space between the spools. The heat treatment is done in steps with lower and higher temperatures, followed by carbonization, to promote chemical reactions and carbonization in the electrode coating. This provides high capacity, mechanical strength, and cycle life compared to conventional electrode fabrication methods.

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Solvent-free dry powder processing to make electrode components for lithium-ion batteries with improved long-term performance. The processing involves dry mixing of electrode active material particles with ceramic and carbon particles to form coated particles. These coated particles are then mixed with binder particles to create a composite. The composite is applied to current collectors to make electrodes without using solvents. The dry powder mixing steps provide better particle distribution compared to slurry mixing. The coated particles have a core of active material surrounded by a layer of ceramic and carbon particles. This multilayer coating improves lithium ion cycling stability and reduces transition metal dissolution compared to slurry-cast electrodes.

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Method for manufacturing lithium-ion battery cells with improved edge sealing to prevent corrosion and oxidation. The method involves applying a conformal coating to the edges of the aluminum pouch layers that enclose the electrodes. The coating is a photocatalytic polymer precursor that cures when exposed to UV light. The coating blocks any ground path between the exposed pouch edges and prevents lithium-aluminum alloying and oxidation. It's applied using spray or dip methods and cures at room temperature in under 20 seconds. The coating composition includes photoinitiators, urethane acrylate oligomers, acrylate monomers, and polyamines.

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Pre-lithiated electrodes for lithium-ion batteries that have reduced capacity loss over time compared to conventional electrodes. The pre-lithiation process involves adding a lithium silicate compound to the electrode active material in an oxygen-containing environment with low humidity. This forms a lithium reservoir in the electrode that compensates for lithium loss during cycling, especially in the first cycle. The pre-lithiated electrode can have a total capacity loss of less than 5% after cycling compared to conventional electrodes that lose more lithium during cycling.

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A metal-organic framework (MOF) electrolyte layer for lithium batteries that improves ion transport compared to crushed or degraded MOFs. The MOF electrolyte layer has a porous MOF structure with a solvated salt absorbed in the pores. The anions of the solvated salt interact with the MOF framework metal atoms, transforming the pores into ionic channels. This provides an open pore structure for efficient ion transport through the MOF electrolyte layer. The MOF electrolyte layer also has low density and surface area for improved battery performance.

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Anode material for lithium-ion batteries that improves performance and reduces cost compared to traditional graphite anodes. The anode material is a composite of titanium oxide (TiO2) nanoparticles embedded in a matrix of titanium niobium oxide (TixNbyOz) with specific ratios of x, y, and z. The composite anode has higher capacity, power, and cost than just TiO2, due to the niobium-containing matrix. It can be made by ball milling TiO2 with niobium precursors, followed by heating and forming into anodes for batteries.

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Electrode design for lithium-ion batteries that scavenges hydrogen fluoride (HF) generated during battery operation to prevent transition metal dissolution and degradation. The electrode active material is combined with ceramic HF scavengers like Li2SiO3, LiAlO2, or Li2O-Al2O3-SiO2. These ceramic scavengers trap HF protons without releasing water molecules at elevated temperatures. The ceramic HF scavengers can be embedded into the electrode active material or added to the electrode coating. The ceramic scavengers prevent HF-induced transition metal dissolution from the electrode active material.

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Bipolar battery design that combines lithium ion battery electrode materials and capacitor electrode materials to achieve a desired combination of energy density and power density. The battery has bipolar electrodes with current collectors coated on opposite sides with layers of lithium ion battery electrode materials. Intermediate bipolar electrodes have current collectors coated with layers of lithium ion battery electrode materials or capacitor electrode materials. The bipolar electrodes are separated by non-liquid electrolyte layers. The capacitor electrode layers in the intermediate bipolar electrodes provide high power density compared to lithium ion battery electrodes. The lithium ion battery electrodes in the bipolar electrodes provide higher energy density.

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Solid-state battery electrolyte with improved interfacial contact between the electrodes and the electrolyte to enable better battery performance. The electrolyte is a softened version of a conventional oxide or sulfide-based solid electrolyte. It is softened by replacing some of the anions with larger radius anions. This reduces the elastic modulus of the electrolyte to make it more flexible. The softened electrolyte has better interfacial contact with the electrodes compared to the unsoftened electrolyte, especially with the positive electrode.

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Negative electrode material for lithium-ion batteries that can withstand high volume expansion during cycling without fracturing, enabling long cycle life. The negative electrode material is a core of silicon, silicon alloys, or tin alloys coated with a multilayer film. The outer layer is a porous elastomeric siloxane coating with dispersed conductive particles. This coating expands and contracts reversibly to accommodate the core volume changes, preventing fracturing.

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A continuous flow process for lithiating electroactive materials like silicon used in negative electrodes of lithium-ion batteries at room temperature. The process involves dispersing the electroactive material precursor in an electrolyte containing lithium salt, then contacting it with a lithium source to ionize and react with the precursor to form the lithiated electroactive material. The lithiation can be controlled by electrochemically discharging the lithiated material to a lower lithiation level. This reduces lithium loss during the first cell cycle compared to conventional lithiation methods.

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Fabrication methods for high capacity lithium-ion battery electrodes and cells using silicon-based host materials with improved cycling performance. The methods involve coating a current collector with a slurry containing silicon particles, polymeric binders, and naturally occurring carbonaceous filaments. Heat treating the coated current collector forms the electrode with a layer of silicon-based host material. The carbonaceous filaments provide mechanical strength and electrical conductivity to prevent electrode cracking during silicon expansion/contraction. The silicon-based host materials have reduced irreversible capacity loss and capacity fade compared to conventional electrodes.

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Lithium-ion battery cell charging system to mitigate plating and degradation at low temperatures. The system uses carbon nanotube sheets on the battery cells that heat them when current is passed through when the cell temperature drops below a threshold. This prevents plating during fast charging and at low temperatures. The sheets are positioned directly on the cells and are controlled by a circuit to provide variable heat-up rates. The sheets can also be combined with other cooling methods like sandwiched foam layers and conductive plates.

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Bipolar capacitor-assisted solid-state lithium ion battery with improved cold-cranking performance. The battery has solid-state electrolyte cells with capacitor material incorporated into the electrodes. The capacitor material, like supercapacitors, stores charge electrostatically and absorbs/de-absorbs ions quickly compared to the active electrode material. This enhances power density. However, the lower capacity of the capacitor material restricts energy density. The bipolar battery architecture mitigates energy density losses by stacking cells with capacitor-assisted electrodes.

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Coating lithium titanate (LTO) electrode material in lithium-ion batteries to suppress gas generation during charging. The coating is formed by pretreating the LTO with compositions containing lithium salts or organophosphorus compounds. This creates a protective surface layer on the LTO particles that reduces reactivity with the electrolyte and prevents hydrogen generation. The coated LTO can be used in batteries without needing high temperature aging to improve cycle life. The coatings can cover 70% or more of the LTO surface area.

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Optimizing the performance and lifetime of lithium-ion batteries by chemically attaching electroactive materials like silicon to a crosslinked polymer matrix. The method involves mixing an electrode slurry containing the electroactive material, conductive filler, and polymer chains with crosslinking precursors. During formation of the electrode, the crosslinking precursors simultaneously chemically crosslink the polymer chains and attach to the electroactive material. This enhances mechanical robustness and interfacial adhesion compared to just adding the electroactive material to a crosslinked binder. The simultaneous crosslinking and attachment optimizes processing and properties.

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