A Novel Cr(2)O(3)/MnO(2-x) Electrode for Lithium-Oxygen Batteries with Low Charge Voltage and High Energy Efficiency

A high energy efficiency, low charging voltage cathode is of great significance for the development of non-aqueous lithium-oxygen batteries. Non-stoichiometric manganese dioxide (MnO(2-x)) and chromium trioxide (Cr(2)O(3)) are known to have good catalytic activities for the discharging and charging processes, respectively. In this work, we prepared a cathode based on Cr(2)O(3) decorated MnO(2-x) nanosheets via a simple anodic electrodeposition-electrostatic adsorption-calcination process. This combined fabrication process allowed the simultaneous introduction of abundant oxygen vacancies and trivalent manganese into the MnO(2-x) nanosheets, with a uniform load of a small amount of Cr(2)O(3) on the surface of the MnO(2-x) nanosheets. Therefore, the Cr(2)O(3)/MnO(2-x) electrode exhibited a high catalytic effect for both discharging and charging, while providing high energy efficiency and low charge voltage. Experimental results show that the as-prepared Cr(2)O(3)/MnO(2-x) cathode could provide a specific capacity of 6,779 mA·h·g(−1) with a terminal charge voltage of 3.84 V, and energy efficiency of 78%, at a current density of 200 mA·g(−1). The Cr(2)O(3)/MnO(2-x) electrode also showed good rate capability and cycle stability. All the results suggest that the as-prepared Cr(2)O(3)/MnO(2-x) nanosheet electrode has great prospects in non-aqueous lithium-oxygen batteries.