Electrochemical behavior and accompanying structural changes of Li2CuO2 and LiCuO2 were examined. Lithium cupric oxide Li2CuO2 was oxidized to LiCuO2 via two two-phase reactions. One-dimensional [CuO4] chains in Li2CuO2 were maintained during the lithium extraction and insertion processes. When the Li2-xCuO2 electrode was cycled at 0.5 mA cm(-2), a rechargeable capacity of 130 mAh g(-1) was obtained with an average voltage of 2.5 V. Lithium extraction from LiCuO2 lead to a production of CuO and oxygen. Lithium insertion into NaCuO2 resulted in a new phase formation of LiNaCuO2.