The Effect of AlPO[sub 4]-Coating Layer on the Electrochemical Properties in LiCoO[sub 2] Thin Films

-coated thin films showed electrochemical properties superior to those of bare film. Moreover, the electrochemical properties of the coated films were affected by the nanostructures of the -coating layer, which was deposited at various deposition temperatures. In particular, coated with deposited at showed optimal capacity retention. It was found that the -coating layer effectively suppressed the increase in the charge-transfer resistance during cycling, as measured by electrochemical impedance spectroscopy. This dependence on the deposition temperature was attributed to the nanostructures of the -coating layer, and to interdiffusion at the interface between the and the nanoscale-coating layer.