Effect of chitosan on deposition of LiCoO₂ thin film for Li-ion batteries

Deposition of LiCoO₂ thin film using chitosan-added precursor solution was found to be a cost-effective way to fabricate cathode for Li-ion thin film batteries. The structures and electrochemical performance of such LiCoO₂ cathode were characterized by using an X-ray diffracotmeter (XRD), FTIR and charge-discharge tests. After annealing at ca. 500 °C, the results of XRD showed that the LiCoO₂ gel started to crystallize and showed hexagonal phase with a space group of R3̄m. The enhanced stability of the precursor solution by the addition of chitosan is attributed to the complexation between metal ions and the -NH₂ groups of chitosan.The electrochemical behaviour for the deposited films calcined at 700 °C for 4 h was also characterized by charge-discharge test. The result revealed that the film deposited from chitosan-containing precursor solution possesses an initial discharge capacity of 129 mAh g^{- 1}.