Facile synthesis of spinel MgCo2O4 nanosheets for high-performance asymmetric supercapacitors

Abstract

Two dimensional (2D) spinel cobaltite has great potential in electrochemical energy storage due to its unique structure and remarkable performance. Herein, we reported for a successful synthesis of MgCo2O4 nanosheets through direct hydrothermal decomposition of a mixed aqueous solution of MgCl2 and CoCl2 and formic acid (HCOOH, FA) at 200 °C for 6 h. The MgCo2O4 nanosheets yield a specific capacitance of 1431.2 F·g−1 at 1.0 A·g−1 in a three-electrode system and a high energy density of 32 Wh·kg−1 at a power density of 800 W·kg−1 in an aqueous asymmetric supercapacitor (MgCo2O4 thin sheets (+)//active carbon (AC) (−)). The MgCo2O4 nanosheets display potential applications in electrochemical energy storage.