Three-dimensional network of Mn 3 O 4 /reduced graphene oxide aerogel with improved electrochemical performances of sodium-ion batteries

It is widely known that transition-metal oxides, including Mn 3 O 4, 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 Mn 3 O 4 electrode during the sodiation/desodiation process. In this study, Mn 3 O 4 /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 Mn 3 O 4 nanoparticles, and formation of a three-dimensional network of rGO nanosheets can all occur concurrently during the synthesis process, ensuring an even distribution of Mn 3 O 4 nanoparticles on the rGO sheet. The Mn 3 O 4 /rGO aerogels exhibit a good electrochemical sodium storage performance when tested as an anode material. In the initial cycle, the Mn 3 O 4 /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 Mn 3 O 4 , 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 Mn 3 O 4 /rGO aerogels can be further explored for the development of sodium-ion batteries and the synergistic effect contributed by both rGO aerogel and Mn 3 O 4 nanoparticles offers an alternative strategy to mitigate the issues associated with Mn 3 O 4 .