Preparation of activated carbons from mesophase pitch and their electrochemical properties

Abstract

The influences of molar ratio of KOH to C and activated temperature on the pore structure and electrochemical property of porous activated carbon from mesophase pitch activated by KOH were investigated. The surface areas and the pore structures of activated carbons were analyzed by nitrogen adsorption, and the electrochemical properties of the activated carbons were studied using two-electrode capacitors in organic electrolyte. The results indicate that the maximum surface area of 3 190 m 2 /g is obtained at molar ratio of KOH to C of 5:1, the maximum specific capacitance of 122 F/g is attained at molar ratio of KOH to C of ‫,1׃4‬ and 800 ℃ is the proper temperature to obtain the maximum surface area and capacitance.

Efficient coupling of MnO2/TiN on carbon cloth positive electrode and Fe2O3/TiN on carbon cloth negative electrode for flexible ultra-fast hybrid supercapacitors

“…For practical applications, it is important to evaluate the leakage current and self-discharge performance to analyze the properties of the fabricated pseudocapacitive electrode. 20 In order to obtain the leakage current of the electrode, the MnO 2 /TiN/CC is charged to 1 V under the current of 2 mA, and then a current flowing as the leakage current is applied to the electrode to keep the electrode potential at 1 V. Fig. 3(h) shows the curve of leakage current, which indicate that the leakage current drops to 0.048 mA in a short time and remains stable in the next two hours.…”

“… 23 The low leakage current value of the MnO 2 /TiN/CC suggests fewer reaction of byproduct impurities on the electrode and insignificant diffusion of electrolyte ions on the electrode surface due to the concentration gradient. 20 The potentials of the MnO 2 /TiN/CC were then further measured for 25 h, and the time courses of the open circuit potential are shown in Fig. 3(i) , which corresponds to the self-discharge process.…”