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 10000 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.