Combined Ag And Cu-Doping Of Mno2-X Improves Li-Ion Battery Capacity Retention On Cycling

Amorphous materials are of significant interest as electrodes in electrochemical storage due to their potential for relatively high cation insertion. Manganese , doped manganese oxides, in a variety of polymorphs including amorphous variants, show high charge storage capacities when implemented as electrodes in Li-ion batteries. However, the robustness of low crystallinity Mn-oxides after many charge-discharge cycles has been little reported and is difficult to characterise. Here, doping of MnO2-x prepared at low temperatures with Ag and Cu is shown to produce the beta MnO2 polymorph and significantly improve the cyclability of electrodes compared to those doped with Ag, Fe and Ti. The capacity on the 5th charge-discharge cycle is 647 mAh g(-1) for the combined Ag and Cu doped material and the capacity degradation slows considerably out to 100 cycles for the best performing nanomaterial composition of Ag0.004Cu0.002MnO2-x. This work contributes to the development high capacity Li-ion battery electrodes with excellent cyclability and low series impedance.