A high performance asymmetric supercapacitor based on carbon fiber coated with MgCo2O4 nanobrush

Abstract Asymmetric supercapacitor (ASC) has recently attracted increasing interest, due to a large capacitance and application potential in energy storage. However, its relatively poor performances are still limited practical applications, owing to the challenges in the rational modification of fiber-shaped substrates with sophisticated nanostructure. Herein, a fiber-shaped electrode consisting of MgCo 2 O 4 nanobrush supported on a carbon fiber is prepared through a facile hydrothermal process, which displays a largely specific capacitance of 854 mF cm −2 at 2.5 mA cm −2 . Based on this sophisticated nanobrush structure, an ASC is fabricated using these materials as the positive electrode and active carbon fiber (ACF) as the negative electrode, which exhibits excellent supercapacitive performances with a wide potential window of 1.2 V, a high volume capacitance of 12.64 F cm −3 and long-term cycling stability after 8000 cycles at a current density of 0.5 A cm −3 .