Reversible Electrochemical Conversion Reaction of Li2O/CuO Nanocomposites and Their Application as High-Capacity Cathode Materials for Li-Ion Batteries

Novel Li2O/CuO nanocomposites were prepared by ball-milling the CuO and Li2O nanoparticles with rigid TIN nanopowders, where TiN nanopowders act as a conductive substrate to immobilize the electroactive nanolayer of a biphasic Li2O/CuO mixture. The as-prepared samples demonstrate a superior electrochemical capacity of 560 mA g(-1) at a moderate charge-discharge rate of 50 mA g(-1) and also exhibit a quite high reversible capacity of similar to 438 mAh g(-1) even at a very high rate of 500 mA g(-1) at room temperature. CV and XRD analyses revealed that the Li2O/CuO nanocomposite can realize nearly a three-electron transfer through electrochemical conversion of Cu2O/Cu to LiCuO2 and vice versa, involving lithium intercalation and deintercalation. This conversion reaction can proceed reversibly and rapidly as long as the different phases of the cathode-active particles are well-dispersed and closely contacted to create electrochemically favorable nanodomains in the electrode. The experimental results demonstrated in this study suggest the possibility to use inexpensive multivalent metal oxides as high-capacity cathode materials for construction of future-generation lithium-ion batteries through an electrochemical conversion mechanism.