NONAQUEOUS ELECTROLYTE BATTERY AND PROCESS FOR PRODUCING THE SAME

摘要

This invention provides a nonaqueous electrolyte battery comprising a negative electrode containing a negative electrode active material in which lithium ions are inserted and desorbed at a potential of not less than 1.2 V with respect to the lithium potential, which nonaqueous electrolyte battery can suppress the evolution of gas therefrom. The nonaqueous electrolyte battery comprises a nonaqueous electrolyte containing an electrolyte salt and a nonaqueous solvent, a positive electrode and a negative electrode and is characterized in that the negative electrode comprises a main active material, in which lithium ions are inserted and desorbed at a potential of not less than 1.2 V with respect to the lithium potential, and a sub-active material, in which lithium ions are inserted at a potential of at least 1.2 V lower than the lithium potential, and lithium in an amount of not less than one sec in terms of a spin-lattice relaxation time (T₁) as determined by solid Li-NMR measurement is present in the main active material in the negative electrode. There is also provided a process for producing the above nonaqueous electrolyte battery comprising a nonaqueous electrolyte, a positive electrode, and a negative electrode (a main active material and a sub-active material in the negative electrode), characterized in that, in an initial cycle, the negative electrode potential is lowered at least once to not more than 0.8 V with respect to the lithium potential.