Molten salt template-assisted synthesis of N, S-codoped hierarchically porous carbon nanosheets for efficient energy storage

To enrich the type of carbons for double-layer supercapacitors and optimize their electrochemical performances, N/S co-doped hierarchical porous carbons (KISPCs) with well-balanced pore characteristic have been prepared by taking ginkgo leaf as carbon source and KCl/K2CO3 molten-salt as template/activation agent. The as-obtained carbons possess a well-developed interconnected sheet-like structure, accompanying with high N, S and O contents, conductive to abundant ions transport channels and exposure of more ions-accessible active sites. Moreover, the types and contents of surface functional groups of hierarchical porous carbon could also be adjusted by K2CO3 content. A symmetrical supercapacitor was assembled to validate its electrochemical performance. The KISPCs electrodes manifest a specific capacitance of 215.2 F g(-1) at 0.05 A g(-1), splendid capacitance retention of 78.9 % (169.8 F g(-1) at 20 A g(-1)) and exceptional cycling stability with only 1.6 % capacity decay after 10000 charge/discharge cycles. This work can afford promising new tactics for the preparation of hierarchical porous carbon nanosheets and offer insights into the application of energy storage fields.