Preparation and electrochemical properties of a Li 2CuO 2–Li 2NiO 2 solid solution as a lithium-intercalation electrode

Abstract

Solid solution materials of Li 2CuO 2 and Li 2NiO 2 were studied with respect to their electrochemical performance and crystal structure. The Li 2CuO 2–Li 2NiO 2 system shows a solid solution over the whole composition range with the orthorhombic structure. Pure Li 2CuO 2 has a reversible capacity of only 100 mA h/g, and the capacity of Li 2Cu 1− x Ni x O 2 increased with increasing the content of Ni. The maximum capacity of 250 mA h/g is obtained for Li 2Cu 0.5Ni 0.5O 2, and it exhibits a good reversibility for charge and discharge cycles. The orthorhombic Li 2CuO 2 undergoes a phase change to the monoclinic LiCuO 2 during lithium deintercalation, while nickel-rich compositions show a new phase that is different from either the original orthorhombic or monoclinic structure.