Controllable synthesis of MnO2 with different structures for supercapacitor electrodes

In this paper, MnO2 with four different structures (nanosandwiches, microsticks, nanowires and microflowers) are synthesized through varying reaction conditions, including the concentration of KMnO4 solution and hydrothermal reaction temperature. Through comparing experimental data, it can be concluded that the microstructure of MnO2 plays a vital role in electrochemical performance. Among the four structures, the microflower has the largest specific surface area for more electroactive sites, and thus demonstrates an excellent charge storage performance of 185 F/g at a current density of 0.5 A/g and cycling stability with a capacitance retention rate of 85% and a coulombic efficiency of nearly 100% after 10,000 charge-discharge cycles.