Preparation of mulberry‐like RuO 2 electrode material for supercapacitors

As a newly emerging excellent energy storage device, supercapacitors have been widely studied due to their unique advantages. Electrode material is one of the key components that determine the performance of a supercapacitor. Among the various electrode materials of supercapacitors, RuO2 has attracted great attention in the scientific community due to its high theoretical energy storage capability and excellent stability. However, most RuO2 materials suffer the problem of low specific surface area, causing a much lower actual capacitance value compared to the theoretical performance of the material. In this work, a mulberry-like RuO2 electrode material with large specific surface area (159.4 m2·g−1) was successfully synthesized by a facial hydrothermal method. The electrochemical characterization has shown that the RuO2 possesses a high specific capacitance of 400 F·g−1 at a current density of 0.2 A·g−1 and good capacitance retention rate of 84.7% after 6000 charge/discharge cycles under a current density of 10 A·g−1. The energy densities and power densities of the RuO2-AC supercapacitor vary from 25.0 to 11.7 Wh·kg−1 and 160 to 10,560 W·kg−1 at current density ranging from 0.2 to 10.0 A·g−1, respectively.