Mn3O4 tetragonal bipyramid laden nitrogen doped and hierarchically porous carbon composite as positive electrode for high-performance asymmetric supercapacitor

Abstract Nanostructured metal oxides have shown outstanding promise for electrochemical energy storage, but are usually limited to low rate capability and poor cycling performance caused by irregular shapes and aggregation of nanoparticles at high mass loading (>1 mg cm−2). To solve these problems, we report the design of a novel Mn3O4 tetragonal bipyramid laden nitrogen doped and hierarchically porous carbon (Mn3O4 TB/NHPC) composite with higher mass loading (～5 mg cm−2) for high-performance energy storage. The homogeneous dispersion of Mn3O4 TBs on NHPC with 3D architecture provides excellent electron transfer, and its hierarchically porous structure with large mesopore volume facilitates rapid ion transport. To achieve wide working potential window, an asymmetric supercapacitor of 1.8 V is assembled with Mn3O4 TB/NHPC composite and NHPC as the positive and negative electrode, respectively. Benefiting from these advantages, the supercapacitor exhibits excellent rate capability (80% of the capacitance retention from 0.5 to 10.0 A g−1) and high energy density (34.7 Wh kg−1 at 450 W kg−1). More importantly, the assembled device demonstrates a splendid cycling performance (97% capacitance retention after 10000 cycles). Morphology controlled Mn3O4 laden porous carbon composites with remarkable capacitive performance inspire us to develop superior electrode materials for energy storage.