Preparation and electrochemical properties of a Li2CuO2–Li2NiO2 solid solution as a lithium-intercalation electrode

Solid solution materials of Li2CuO2 and Li2NiO2 were studied with respect to their electrochemical performance and crystal structure. The Li2CuO2–Li2NiO2 system shows a solid solution over the whole composition range with the orthorhombic structure. Pure Li2CuO2 has a reversible capacity of only 100 mA h/g, and the capacity of Li2Cu1−xNixO2 increased with increasing the content of Ni. The maximum capacity of 250 mA h/g is obtained for Li2Cu0.5Ni0.5O2, and it exhibits a good reversibility for charge and discharge cycles. The orthorhombic Li2CuO2 undergoes a phase change to the monoclinic LiCuO2 during lithium deintercalation, while nickel-rich compositions show a new phase that is different from either the original orthorhombic or monoclinic structure.