Hierarchical structure of CoFe2O4 core-shell microsphere coating on carbon fiber cloth for high-performance asymmetric flexible supercapacitor applications

Abstract

Designing hierarchical core-shell microsphere electrode materials with ideal composition and structure is a promising strategy to improve electrochemical properties of flexible electrodes. Here, we design and synthesize hierarchical CoFe2O4 core-shell microsphere coat on carbon fiber cloth (CFC) via a mild hydrothermal. The as-synthesized cobalt ferrite spheres have three stages of nanospheres, microspheres, and core-shell microspheres. The CFC/CoFe2O4 core-shell microsphere electrode shows an outstanding capacitance of 393 mF cm−2 at 1 A cm−2 and outstanding hydrophilicity. An aqueous flexible asymmetric supercapacitor (AFAS) at 1.6 V achieves a well specific capacitance of 226.2 mF cm−3 at a current density of 1 A cm−3, and the maximum energy density is 75.4 mWh cm−3 at a power density of 1151.2 mW cm−3. AFAS, with its advantages of low cost, high capacity, and simple manufacturing process, is one of the excellent candidate flexible asymmetric supercapacitors for the new generation of high-performance supercapacitors. These obvious effects have showed that the CFC/CoFe2O4 electrode may supply us a new chance for designing high-performance flexible supercapacitors.