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

Abstract

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 mAh g−1 at a moderate charge−discharge rate of 50 mA g−1 and also exhibit a quite high reversible capacity of ∼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 stu...