Manganese Dioxide/Ant-Nest-Like Hierarchical Porous Carbon Composite with Robust Supercapacitive Performances

Abstract

Fullerenes (C60) are made of sp2-hybridized carbon atoms, like carbon nanotubes and graphene. Herein, C60 is sheared by chemical methods, involving alkali solution reactions that start to break carbon–carbon bonds, and then, the MnO2/three-dimensional ant-nest-like hierarchical porous carbon composite (MnO2/ANHPC) is successfully prepared. ANHPC has the ant-nest-like hierarchical porous structure, and MnO2 is deposited on the surface of ANHPC. The MnO2/ANHPC composite reveals a high specific capacitance of 662 F g–1 at 1 A g–1 since it is the combination of both double-layer capacitances of ANHPC and pseudocapacitance of MnO2. The symmetric supercapacitor using the MnO2/ANHPC composite as the active material shows excellent rate performance and outstanding cycle stability (with 93.4% capacity retention rate after 5000 cycles at 1 A g–1) as well as a remarkable energy density of 21.5 Wh kg–1. The improved supercapacitive performance is closely related with the integrated advantage of the 3D ant-nest-like hierarchical porous structure of ANHPC, stacked graphene sheets of linked hexagonal rings after chemically sheared C60, and pseudocapacitance behavior of MnO2. Therefore, the design and preparation of the MnO2/ANHPC composite is a promising strategy for the active material of a high performance supercapacitor.