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

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 Mn 3 O 4 tetragonal bipyramid laden nitrogen doped and hierarchically porous carbon (Mn 3 O 4 TB/NHPC) composite with higher mass loading (～5 mg cm −2 ) for high-performance energy storage. The homogeneous dispersion of Mn 3 O 4 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 Mn 3 O 4 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 Mn 3 O 4 laden porous carbon composites with remarkable capacitive performance inspire us to develop superior electrode materials for energy storage.