Long-term cycling effects on thin-film lithium batteries of 10 mu m thick Li/LIPON/LiCoO2 deposited on a flexible substrate were investigated. Scanning electron microscopic and Raman spectroscopic analysis results revealed that cycling resulted in an increased fraction of (003)-oriented grains in originally (101)/(104)-oriented LiCoO2 films in a hexagonal structure followed by a phase transition to a low temperature spinel phase and shrinkage of the LiCoO2 films and roughening of the Pt-LiCoO2 interface, leading to a capacity decline of similar to 27% over 1040 cycles. The data contribute to a basic understanding of the structural causes responsible for the internal cell resistance and the cycle life of all-solid-state thin-film batteries.