Patent ID: 8383268

Claim:
A method for manufacturing a lithium ion secondary battery having a thin film solid electrolyte consisting of a lithium ion conductive inorganic substance selected from the group consisting of a lithium ion conductive crystal of Li 1+x+y Al x Ti 2−x Si y P 3−y O 12 (0≦x≦1,0≦y≦1) and a lithium ion conductive glass-ceramic comprising Li 1+x+y Al x Ti 2−x Si y P 3−y O 12 (0≦x≦1,0≦y≦1) as a predominant crystal phase, comprising a step of preparing a target material from glass-ceramic powder comprising Li 1+x+y Al x Ti 2−x Si y P 3−y O 12 (0<x <1,0<y<1) as a predominant crystal phase by using Li 3 PO 4 as an inorganic binder, a step of coating the lithium ion conductive inorganic substance directly on an electrode material or materials for a positive and/or negative electrode to form an amorphous layer of 20 μm or below, by using the target material and by a method selected from the group consisting of sputtering, laser abrasion and plasma coating, and a step of forming the thin film solid electrolyte by crystallizing the amorphous layer.