Sputtered LiCoO₂ Cathode Materials for All-solid-state Thin-film Lithium Microbatteries

This review article presents the literature survey on radio frequency (RF)-magnetron sputtered LiCoO₂ thin films used as cathode materials in all-solid-state rechargeable lithium microbatteries. As the process parameters lead to a variety of texture and preferential orientation, the influence of the sputtering conditions on the deposition of LiCoO₂ thin films are considered. The electrochemical performance is examined as a function of composition of the sputter Ar/O₂ gas mixture, gas flow rate, pressure, nature of substrate, substrate temperature, deposition rate, and annealing temperature. The state-of-the-art of lithium microbatteries fabricated by the rf-sputtering method is also reported.