Abstract: Prelithiated negative electrodes are prepared under controlled conditions. Lithium foils are laminated onto active material layers using sufficient pressure such that heat is generated upon initiation of reaction of between lithium and the active material. The reaction proceeds to completion with the laminated assembly maintained under solvent-free, temperature controlled conditions for up to about 24 hours. The prelithiated negative electrode active material has a voltage against lithium metal of not more than about 1V at a value of lithium uptake of 10% of capacity, and irreversible capacity loss associated with the active material has been eliminated. Roll-to-roll processes and apparatus are described for safe manufacture of hundreds of meters of the prelithiated negative electrodes which can be taken up in roll form to be cut and assembled with other components to form lithium ion cells.

Abstract: Electrolytes are described that involve lithium salt blends and compatible nonaqueous solvents that provide to high rate performance, charging and discharging, of lithium ion cells using silicon-based active materials, such as silicon suboxide composites, for example, silicon oxide/silicon/carbon composites. The lithium salts generally were a blend of LiPF6, and LiFSI or LiTFSI. The solvents generally comprised fluoroethylene carbonate and dimethyl carbonate with optional cosolvents and/or other additives.