Sputtered Al-doped lithium manganese oxide films for the cathode of lithium ion battery: The post-deposition annealing temperature effect

摘要

In this paper, lithium-excess Al-doped lithium manganese oxide films were prepared by R.F. magnetron sputtering at ambient temperature. X-ray diffraction, scanning electron microscopy, Raman spectra and constant current charge/discharge cycling were employed to study the post-deposition annealing effect. It has been found that the annealing temperature threshold for a single spinel phase was about 600 deg C in oxygen atmosphere. The films annealed at 500 deg C showed a composite structure with fine particles, which resulted in good capacity retention capability in both 4 V and 3 V regions. When annealed at 700 deg C, a lithium deficient phase appeared, which led to structure reorganization and reduced adhesion of the cathode films to underlying Pt films, which caused poorer capacity retention capability.