A dual-template strategy of N and O co-doped hierarchically porous carbon derived from waste tea for excellent supercapacitor performance

The exploration of biomass-derived hierarchically porous carbon is of great significance to supercapacitors (SCs). Herein, the N and O co-doped hierarchically porous carbon (N-O-HPC) derived from waste tea leaves was prepared by a facile dual-templating (ZnCl2 and Mg5(OH)2(CO3)4) approach. When utilized as an electrode for SCs, the as-prepared N-O-HPC exhibits a large specific capacitance of 321 F g−1 at 1 A g−1. Moreover, the assembled N-O-HPC//N-O-HPC symmetric SCs exhibit a wide voltage window (1.8 V), a high energy density (28.01 Wh kg-1 at 450 W kg-1) and a long cycle life after 10000 cycles (90.7%). These results demonstrate that as-prepared N-O-HPC exhibits a great potential for SCs, highlighting the significance of biomass derived carbon materials.