Abstract: LiFePO₄ thin films have been successfully fabricated by using pulsed laser deposition (PLD) coupled with high temperature annealing. The morphology, structure and electrochemical behaviors of the obtained thin films were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), the charge/discharge and cyclic voltammetry (CV) measurements. These results indicated that LiFePO₄ thin films had a well-crystallized olivinetype structure before and after annealed at 650 ℃. The annealed LiFePO₄ thin film exhibited a 3.45/3.40 V plateau vs Li⁺/Li in the discharge/charge curves. The first discharge capacity was found to be 27 mAh•g^－1 and the discharge capacity kept 49% of the first discharge capacity after cycling 100 times. The low reversible capacity and poor cycling performance of LiFePO₄ thin films fabricated by pulsed laser deposition may be due to the lower electrochemical activity of the large particle on the surface of thin film electrode, the existence of part of Fe₂O₃ produced by the high temperature annealing and the poor conductivity of LiFePO₄ material.

Key words: Pulsed laser deposition, Li ion batteries, LiFePO₄, Thin films