Patent ID: 8765306

Claim:
An activated lithium ion battery after a formation cycle with a charge to at least about 4.35V, the activated battery comprising: a positive electrode comprising a lithium rich lithium metal oxide intercalation composition represented by the formula Li 1+x M y O 2 , where M refers to a mixture of metal ions, y ranges from about 0.65 to about 0.99 and x ranges from about 0.05 to about 0.25; a negative electrode comprising a lithium intercalation/alloy composition and a solid electrolyte interface (SEI) layer associated with the lithium intercalation/alloy composition; a separator between the positive electrode and the negative electrode; and an electrolyte comprising lithium ions, wherein the formation cycle to form the activated battery comprises: performing an initial charge of the battery to a voltage of no more than about 4.3 volts; after completing the initial charge, holding the battery at an open circuit for a rest period of at least about 12 hours; and performing a second charge after the completion of the rest period to the voltage of at least about 4.35 volts, and wherein after discharge, the negative electrode separated from the battery with the solid electrolyte interface (SEI) layer remaining associated with the lithium intercalation/alloy composition has an onset decomposition temperature of at least 130° C. as determined based on a differential scanning calorimetry (DSC) measurement.