Lithium ion secondary battery and solid electrolyte therefor

摘要

A solid electrolyte and a lithium ion secondary battery A solid electrolyte for a lithium ion secondary battery has a laminate of at least two layers. The thickest layer of the laminate comprises lithium ion conductive crystalline, preferably lithium ion conductive glass-ceramics having a predominant layer of Li_1+x+y(Al, Ga)_x(Ti, Ge)_2-xSi_yP_3-yO₁₂ where 0<=x<=1, 0<=y<=1. In a preferred embodiment, thickness of an electrolyte layer comprising the lithium ion conductive glass-ceramics is 150 mum or below and thickness of an electrolyte layer which does not contain lithium ion conductive glass-ceramics or contains only a small amount of lithium ion conductive glass-ceramics is 50 mum or below.