Abstract: Improved negative electrodes can comprise a silicon based active material blended with graphite to provide more stable cycling at high energy densities. In some embodiments, the negative electrodes comprise a blend of polyimide binder mixed with a more elastic polymer binder with a nanoscale carbon conductive additive. Electrolytes have been formulated that provide for extended cycling of cells incorporating a mixture of a silicon-oxide based active material with graphite active material in negative electrodes that can be matched with positive electrodes comprising nickel rich lithium nickel manganese cobalt oxides to cells with unprecedented cycling properties for large capacity cell based on a silicon negative electrode active material.

Abstract: A composite coated form of lithium cobalt oxide is described that can achieve improved cycling at higher voltages. Liquid phase and combined liquid and solid phase coating processes are described to effectively form the composite coated powders. The improved cycling positive electrode materials can be effectively combined with either graphitic carbon negative electrode active materials or silicon based high capacity negative electrode active materials. Improved battery designs can achieve very high volumetric energy densities in practical battery formats and with reasonable cycling properties.