Holey two dimensional manganese cobalt oxide nanosheets as a high-performance electrode for supercapattery

Abstract

Two dimensional (2D) nanostructure materials are auspicious for energy storage application due to their excellent electrical conductivity and electrochemical properties. We report a facial synthesis of holey 2D MnCo2O4 nanosheets using bottom-up process and apply the as-synthesized materials as a positive electrode for supercapattery. The fabricated electrode shows an excellent capacity due to the large electrochemical active area and a number of nanoholes in the nanosheets, which allow fast electrochemical redox reaction. The assembled supercapattery coupled with AC negative electrode delivers a specific capacity of 152.7 mAh g−1 at a current density of 5 mA cm−2 with a high specific energy density of 33.8 Wh kg−1 (at a power density of 318.9 W kg−1). Furthermore, the supercapattery shows an excellent cycle stability of ∼85% capacity retention even after 10,000 cycles at a high current density of 30 mA cm−2. The reported simple and versatile fabrication technique allows the synthesis of various metal oxide nanosheets with the 2D structure as well as with porous nature, offering an interest in various electrochemical applications such as electrocatalyses and biosensors.