High Performance Thin Lithium-Ion Battery Using an Aluminum-Plastic Laminated Film Bag

We have developed a new thin high-capacity lithium-ion battery using a boron-doped mesophase-pitchbased carbon fiber anode, a LiBF 4 ·EC/GBL organic electrolyte and an aluminum-plastic laminated film bag. The thin lithium-ion battery exhibited a high energy density of 172 Wh/kg, high discharge performance and a very low swelling under a high-temperature storage. The safety of the thin lithium-ion battery under overcharging tests and oven tests was superior to that of conventional prismatic lithium-ion batteries and polymer lithium-ion batteries. The very low swelling and the excellent safety performance were attributable to the stability of the LiBF 4 -EC/GBL electrolyte against LiCoO 2 cathode material.