Three-dimensional network of Mn3O4/reduced graphene oxide aerogel with improved electrochemical performances of sodium-ion batteries

It is widely known that transition-metal oxides, including Mn3O4, suffer from volume expansion and poor conductivity and thus, result in unsatisfactory cycling stability in the sodium-ion batteries. One approach to overcome these issues is to use reduced graphene oxide (rGO) aerogels as a potential matrix to support the Mn3O4 electrode during the sodiation/desodiation process. In this study, Mn3O4/rGO aerogels are prepared by the hydrothermal process, followed by the freeze-drying process without further heat treatment. The reduction of graphite oxide, deposition of Mn3O4 nanoparticles, and formation of a three-dimensional network of rGO nanosheets can all occur concurrently during the synthesis process, ensuring an even distribution of Mn3O4 nanoparticles on the rGO sheet. The Mn3O4/rGO aerogels exhibit a good electrochemical sodium storage performance when tested as an anode material. In the initial cycle, the Mn3O4/rGO aerogels delivered a high discharge capacity of 947 mAh g−1 and sustained a capacity of 283 mAh g−1 at a current density of 0.1 A g−1 after 100 cycles, with a large Coulombic efficiency of ~ 99%. The excellent cycling stability and improved discharge capacity of the electrode could be due to the hierarchical structures of rGO with nanosized Mn3O4, which can expedite more ion and electron transporting channels from various directions, provide high interfacial sodium storage, and prevent the structure from collapsing. The electrochemical results indicate that the Mn3O4/rGO aerogels can be further explored for the development of sodium-ion batteries and the synergistic effect contributed by both rGO aerogel and Mn3O4 nanoparticles offers an alternative strategy to mitigate the issues associated with Mn3O4.