Investigation of the supercapacitance of ruthenium-based/ hemp stem activated carbon

This work presents the synthesis of amorphous ruthenium-based/hemp stem activated carbon (HSAC) composites by a liquid phase co-precipitation method. It is the first time that a solution of tetramethylammonium bicarbonate is used as the precipitant. The result reveals that the as-synthesized ruthenium oxide particles are small in size and homogenously distributed on the activated carbon surface. Cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) results show that the ruthenium oxide/HSAC composite has a high mass-specific capacitance (652.79 F g−1 at 5 mV s−1) and excellent rate capability. Electrochemical impedance spectroscopy (EIS) experiments further demonstrate that it has a low device series resistance (0.653 Ω), which has a great enhancement by contrast with the state-of-the-art previous reports. High specific capacitance, outstanding cycling stability, and facile preparation conditions make the electrode material potentially promising for energy storage and conversion devices.