Synthesize and Application of Novel Nano-Hierarchical Hollow Manganese Oxide Anode Material with Outstanding Performance for Sodium Ion Battery

Based on the wide availability and low cost of sodium, ambient temperature sodium–ion batteries (SIBs) have the potential for meeting large scale grid energy storage needs. In addition, since sodium is so abundant, SIBs could provide an alternative chemistry to lithium batteries. However, many anode materials for lithium–ion batteries (LIBs) have not yet been explored for SIBs. Among several kinds of metal oxide anode materials, manganese (Mn) salts are naturally abundant, inexpensive, and environmentally friendly. The utilization of MnO_x or their composites as anode material for SIBs is a prospect that should not be neglected. However, most of transition metal oxide anodes suffer from low rate performance and fast capacity fade due to their poor electronic conductivity and large volume changes during the conversion reaction. Nanostructured materials have the potential for achieving high capacity and rate capability resulting from the large specific surface area and the short electronic and ionic transport length in nanoscale.

For the first time, we have prepared hierarchical hollow MnO₂ by utilizing a SiO₂-templating hydrothermal process. Different from the conventional methods, the SiO₂ was only partially dissolved so that the residue serves as a framework to support MnO₂. The results revealed that the novel hollow nanostructure MnO₂ electrode had a specific charge capacity as large as 499 mAh/g at 0.1 C-rate, and it unprecedentedly demonstrates good cycling stability, retaining 89.4% capacitance after 500 cycles at 1 C-rate at 50 ^oC.