Charge/Discharge Performance of Electron Beam Deposited Tin Oxide Thin Film Negative Electrodes

Abstract

Electron beam deposited tin oxide thin films were studied for use as a negative electrode for lithium rechargeable battery. Tin oxide thin films prepared at different heat treatment conditions (temperature and time) were investigated by the implementation of X-ray diffraction analysis, Auger electron spectroscopy, and atomic force microscopy. Charge/discharge performance of these thin films, typically exhibiting capacities higher than 300 mAh/g lasting beyond 100 cycles, were found to depend on the heat treatment temperatures, which influence the structure, grain sizes, and adhesion to the substrate. Capacity was decreased as film thickness increased, but capacity loss was very small in accordance with increase of charge/discharge rate. Using AC impedance analysis, it was found that capacity loss was caused by resistance increase at cut off voltage under 0.1 V. Lithiated SnO₂/PAN/V₂O₅ type full cell showed the capacity of 200 mAh/g, with active voltage of 2.0-2.7 V.