Surface and diffusion charge contribution study of neem leaves derived porous carbon electrode for supercapacitor applications using acidic, basic, and neutral electrolytes

摘要

Biowastes derived carbon based materials are recently gaining attention due to their extraordinary surface and conductive characteristics. Herein, neem leaves derived porous carbon (NAC) with a 3D framework and interconnected pores are synthesized which shows hierarchal pore size distribution along with good conductivity that makes it a suitable electrode material for supercapacitors. However, the surface charge contribution highly affects the electrochemical performance of the electrodes. In addition, a high fraction of surface charge contribution suggests the fast electrochemical kinetics and hence shows the ability of the electrode to work at a high charge-discharge rate. Therefore, the NAC electrode showed a maximum surface contribution of 72% in 6M KOH electrolyte as compared to 1M H2SO4 (21%) and 1M Na2SO4 (20%) electrolyte. Furthermore, the NAC electrode shows a specific capacitance value of 178 F/g using a 6M KOH electrolyte, which is much higher than 93 F/g for 1M H2SO4 and 136.7 F/g for 1M Na2SO4 electrolyte at the constant scan rate of 5 mV/s. Therefore, these results confirm that the study of surface and diffusion charge contribution gives new directions to tune the electrochemical performance of supercapacitor electrodes.