Highly Uniform MnCo2O4 Hollow Spheres‐Based All‐Solid‐State Asymmetric Micro‐Supercapacitor via a Simple Metal‐Glycerate Precursor Approach

Abstract

Developing a high‐energy‐density all‐solid‐state asymmetric micro‐supercapacitor (AMSC) still remains a big challenge. Herein, a simple metal‐glycerate precursor strategy is used for the synthesis of highly uniform MnCo2O4 hollow spheres, and the all‐solid‐state AMSC is fabricated by MnCo2O4 hollow spheres. It is found that the MnCo2O4 hollow sphere electrode processes a high specific capacitance (0.80 F cm−2) at 2 mA cm−2 and an excellent cycling stability (99% capacitance retention after 2000 cycles). The as‐fabricated all‐solid‐state AMSC displays a high energy density of 0.052 mWh cm−3, a high power density of 320 mW cm−3, and a long cycling life (95.7% capacitance retention after 10 000 charge/discharge cycles). In addition, the all‐solid‐state AMSC can be easily assembled in series to achieve a desirable output voltage, which can drive a light‐emitting diode. This work demonstrates that the MnCo2O4 hollow spheres can be a promising electrode material for a stable, high‐energy‐density micro‐supercapacitor (MSC).