Preparation of lithium thin film and alloy thin film by gas deposition method and their electrode properties

Abstract

We have succeeded to make a Li metal thin film in the range of 1-20 um on copper foil or plastic thin film by gas-deposition method. The Li thin films showed almost the same discharge capacity as a conventional Li metal foil made by roll-pressing method. Alloy thin film electrode of a Sn-35mass % Cu also has been prepared on copper film by the gas-deposition method. The gas-deposited electrode showed much higher capacity retention ratio (87% after 50 cycles) than the conventional pasted electrode (20% after 50 cycles). The initial irreversible capacity loss of roughly 30 % in the alloy electrode have been suppressed successfully by pre-doping of lithium in the alloy electrode using the lithium thin film prepared on the plastic sheet.