Unique amorphous manganese oxide/rGo anodes for lithium-ion batteries with high capacity and excellent stability

Abstract

The utilization of manganese oxide anode materials in lithium-ion batteries is hindered by low conductivity, high stress/strain, volume expansion, and high over potential in the crystalline structure during cycling. Compared with crystal oxide, amorphous oxide has attracted attention for its weak chemical bond force and its low stress change during the phase change process, but few reported in lithium-ion batteries. This work combined both advantages of amorphous manganese oxide (AMO) and reduced graphene oxide (rGo) to produce a unique AMO/rGo composite electrode material through one-step chemical reduction the KMnO4 in graphene oxide containing solution. The rGo-supported porous amorphous structure of manganese oxide brought special character by reducing the stress/strain of the conversion reaction, thus ensuring a high capacity and high stability. The high electronic and lithium-ion conductivity of graphene also enhanced the rate capability. As a result, the as-synthesized AMO/rGo exhibited a large reversible specific capacity (784 mA hg−1 at the current density of 1 A g−1 over 500 cycles) and superior rate capability, making it a potential candidate as high-performance electrode material for long-term cycling in lithium-ion batteries.