Coupling of Mn 2 O 3 with Heteroatom-Doped Reduced Graphene Oxide Aerogels with Improved Electrochemical Performances for Sodium-Ion Batteries.

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 Mn 2 O 3 , are promising for low-cost, eco-friendly energy storage/conversion. Due to its high theoretical capacity, Mn 2 O 3 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 Mn 2 O 3 with heteroatom-doped reduced graphene oxide (rGO) aerogels synthesised via the hydrothermal method with a subsequent freeze-drying process. The cubic Mn 2 O 3 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 Mn 2 O 3 . After 100 cycles, the electrodes retained their capacities of 242, 325, and 277 mAh g -1 , for Mn 2 O 3 /rGO, Mn 2 O 3 /nitrogen-rGO, and Mn 2 O 3 /nitrogen, sulphur-rGO aerogels, respectively. Doping Mn 2 O 3 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.