P-doped hierarchical porous carbon aerogels derived from phenolic resins for high performance supercapacitor

Abstract P-doped hierarchical porous carbon aerogels are prepared by carbonizing the phloroglucin-formaldehyde resins in the presence of ZnCl2 and subsequently being activated by KOH. Phosphoric acid is simultaneously used as the polymerization catalyst and P-doped agent in the preparation procedure. Compared with un-doped sample, P-doped carbon with hierarchical porous structure shows improved electrochemical performance. The prepared sample that activated at 800 °C exhibits good capacitance of 406.2 F g−1 in 6 M KOH at a scan rate of 5 mV s−1. When the scan rate is 500 mV s−1, the specific capacitance still reaches to 267.4 F g−1, demonstrating good rate capability. When 60 mg of active materials is loaded, the mass specific capacitance of the prepared electrode reaches to 348.8 F g−1 at a scan rate of 5 mV s−1, and the maximum area capacitance is 11.35 F cm−2. The energy density of the prepared sample is as high as 16.97 Wh kg−1 at a power density of 200 W kg−1 and reaches to 8.52 Wh kg−1 at 2000 W kg−1. Importantly, after 100,000 charging and discharging cycles, the specific capacitance of the prepared sample is no attenuated, indicating a long-term electrochemical stability.