Abstract: A battery electrode comprises an electrically conductive substrate having an electrochemically active electrode composition supported thereupon. The composition includes an active material capable of reversibly alloying with lithium, which material shows a volume change upon such reversible alloying. The composition includes a buffering agent which accommodates the volume change in the active material and minimizes mechanical strain in the composition. The active composition may further include materials such as carbon. The active material may comprise silicon, aluminum, antimony, antimony oxides, bismuth, bismuth oxides, tin, tin oxides, chromium, chromium oxides, tungsten, and tungsten oxides or lithium alloys of the foregoing. The buffering agent may comprise a metal or a metal oxide or lithium alloys of the foregoing. Also disclosed are batteries which incorporate these electrodes, methods for the fabrication of the electrodes and methods for the fabrication and operation of the batteries.

Abstract: A composite electrode material is fabricated from a first electroactive material which, when incorporated into a cathode of a rechargeable battery, manifests a first mean voltage, a first energy density and a first high cutoff voltage cycle life; and a second electroactive material which, when incorporated into a cathode of the rechargeable battery, manifests a second mean voltage which is less than the first mean voltage, a second energy density which is less than the first energy density, and a second high voltage cutoff cycle life which is greater than the first cycle life. The composite material is characterized in that when it is incorporated into a cathode of the rechargeable battery, it manifests at least one of: a third mean voltage which is greater than the second mean voltage, a third energy density which is greater than the second energy density, and a third high cutoff voltage cycle life which is greater than the first cycle life.