Coupling of Mn2O3 with Heteroatom-Doped Reduced Graphene Oxide Aerogels with Improved Electrochemical Performances for Sodium-Ion Batteries

Abstract

Currently, efforts to address the energy needs of large-scale power applications have expedited the development of sodium–ion (Na–ion) batteries. Transition-metal oxides, including Mn2O3, are promising for low-cost, eco-friendly energy storage/conversion. Due to its high theoretical capacity, Mn2O3 is worth exploring as an anode material for Na-ion batteries; however, its actual application is constrained by low electrical conductivity and capacity fading. Herein, we attempt to overcome the problems related to Mn2O3 with heteroatom-doped reduced graphene oxide (rGO) aerogels synthesised via the hydrothermal method with a subsequent freeze-drying process. The cubic Mn2O3 particles with an average size of 0.5–1.5 µm are distributed to both sides of heteroatom-doped rGO aerogels layers. Results indicate that heteroatom-doped rGO aerogels may serve as an efficient ion transport channel for electrolyte ion transport in Mn2O3. After 100 cycles, the electrodes retained their capacities of 242, 325, and 277 mAh g−1, for Mn2O3/rGO, Mn2O3/nitrogen-rGO, and Mn2O3/nitrogen, sulphur-rGO aerogels, respectively. Doping Mn2O3 with heteroatom-doped rGO aerogels increased its electrical conductivity and buffered volume change during charge/discharge, resulting in high capacity and stable cycling performance. The synergistic effects of heteroatom doping and the three-dimensional porous structure network of rGO aerogels are responsible for their excellent electrochemical performances.