A porous biomass-based sandwich-structured Co3O4@Carbon Fiber@Co3O4 composite for high-performance supercapacitors

Enormous research efforts have been made in the field of design and fabrication of material structure of supercapacitors because of the high complexity in obtaining both high energy and power density. Herein, a hierarchical structure of a Co3O4@biomass-derived carbon fiber @Co3O4 (@BCF@), which consists of hollow porous carbon fiber as the sandwich layer and Co3O4 particles both as an internal shell and an external cladding layer, has been designed and fabricated. Excellent electrochemical performances have been observed for @BCF@supercapacitors, i.e., high specific capacitance (892 F g(-1) at a current density of 0.5 A g(-1)) and long-term cycling stability (retained 88% even after 6000 cycles). Furthermore, they also exhibit potential application values in asymmetric supercapacitors. The selected biomass-derived hollow carbon fiber with porous structure not only provides an ideal electron transfer path to overcome the limitation of high resistance of most oxide electrodes but also serves as a backbone of inner wall space, which could load more Co3O4 particles per unit electrode area to maximize the redox reaction. Therefore, @BCF@with sandwich structure is a promising candidate as an electrode material for the development of energy storage devices in the near future. (C) 2017 Published by Elsevier Ltd.