Structural and Electrochemical Properties of Lithium Nickel Oxide Thin Films

Abstract

LiNiO 2 thin films were fabricated by RF magnetron sputtering. The microstructure of the films was determined by X-ray diffraction and field-emission scanning electron microscopy. The electrochemical properties were investigated with a battery cycler using coin-type half-cells. The LiNiO 2 thin films annealed below 500°C had the surface carbonate. The results suggest that surface carbonate interrupted the Li intercalation and deintercalation during charge/discharge. Although the annealing process enhanced the crystallization of LiNiO 2 , the capacity did not increase. When the annealing temperature was increased to 600°C, the FeCrNiO 4 oxide phase was generated and the discharge capacity decreased due to an oxygen deficiency in the LiNiO 2 thin film. The ZrO 2 -coated LiNiO 2 thin film provided an improved discharge capacity compared to bare LiNiO 2 thin film suggesting that the improved electrochemical characteristic may be attributed to the inhibition of surface carbonate by ZrO 2 coating layer.