Non-aqueous electrolyte secondary battery comprising composite particles

Abstract

A non-aqueous electrolyte secondary battery comprises a positive electrode and a negative electrode capable of intercalating and de-intercalating lithium, a non-aqueous electrolyte and separators or solid electrolytes. The negative electrode contains, as a main component, composite particles constructed in such a manner that at least part of the surface of nuclear particles comprising at least one of tin, silicon and zinc as a constituent element, is coated with a solid solution or an inter-metallic compound composed of the element included in the nuclear particles and another predetermined element which is not an element included in the nuclear particles. To improve the ability of the battery, the composite particles mentioned above can include at least one trace element selected from iron, lead and bismuth. The porosity of a mixture layer at the negative electrode is 10% or more and 50% or less. The amount of the non-aqueous electrolyte, the thickness of the separators or the like is restricted in a specific value. The foregoing construction suppresses occurrence of an internal short circuit between the positive electrode and the negative electrode caused by expansion of the negative electrode materials, thereby achieving a high capacity battery with a superior charge/discharge cycle properties, which is suitable for a high-speed charging.