Potassium chloride templated carbon preparation for supercapacitor

摘要

This is the first report of KCl templated carbon preparation from walnut shell. Activated carbon (AC) with high specific surface area (1958 m(2) g(-1)) was obtained by CO2 activation of KCl templated biochar at 900 degrees C. The electrochemical properties were evaluated by cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscopy. WS-90 had relatively low inner resistance of 1.7 Omega. The specific capacitance was 245.0 F g(-1) in 6 mol L-1 KOH electrolyte at a current density of 0.1 A g(-1), and it can maintain very good cyclic stability with capacitance retention ratio of 95.4% (from 245.0 to 233.7 F g(-1) at current density of 0.1 A g(-1) after 4000 cycles (0.1, 0.5, 1.0 and 5.0 A g(-1) for 1000 cycles, respectively)).