High performance porous carbon through hard–soft dual templates for supercapacitor electrodes

Abstract

A hard–soft dual templates method has been developed for the first time to prepare porous carbons by the direct carbonization of phenol formaldehyde resins (PFs), Zn(NO₃)₂·6H₂O and polyvinyl butyral (PVB) at 1000 °C under Ar gas, in which PFs serve as the carbon source. More importantly, Zn(NO₃)₂·6H₂O and PVB acting as hard and soft template, respectively, can be readily removed through the evaporation process, resulting in pure carbon without any post-treatment, commonly employed. The PF-Zn-PVB-1:5:1 sample has a total BET surface area of 864 m² g⁻¹, and a total pore volume of 0.76 cm³ g⁻¹. An electrode based on the porous carbons exhibits the high specific capacitances of 174.7 F g⁻¹ and 152.8 F g⁻¹ at the current densities of 0.5 and 1.0 A g⁻¹, respectively. It also exhibits a superior rate capability, with high specific capacitance retention at ca. 63.1% at a high current density of 20 A g⁻¹. Significantly, about 96.2% is retained after charging and discharging for 10 000 cycles, revealing its long-term electrochemical stability. The hard–soft dual templates method proposed in the present work is straightforward and effective, and can be utilized to synthesize porous carbons on a large scale for the application of high performance supercapacitors.