NON-AQUEOUS ELECTROLYTE SECONDARY CELL AND ITS CHARGING METHOD

摘要

The negative electrode of the present invention is characterized by its composite particles constructed in such a manner that at least part of the surrounding surface of nuclear particles containing at least one of tin, silicon and zinc as a constituent element, is coated with a solid solution or an inter-metallic compound , which is composed of, the element included in the nuclear particles, and at least one other element except the elements included in the nuclear particles selected from a group comprising group 2 elements, transition elements, group 12 elements, group 13 elements and group 14 elements except carbon of the Periodic Table. The present invention is characterized that the lithium content of the nuclear particles of the composite particles is 40-95 atomic percent of the theoretical limit of lithium content of each constituent element of the nuclear particles. Further, the batteries are first charged at a constant current and upon reaching the predetermined voltage, are charged at a constant voltage. The current density during charging are set at not more than 5mA/cm<2> as a in the area where the positive and negative electrodes face each other. With the foregoing construction, high energy-density non-aqueous electrolyte secondary batteries with superior cycle life properties and a charging method for the same can be obtained.