Molten salt synthesis of two-dimensional sheet-like nitrogen-cobalt co-doped porous carbon nanosheets for high-performance supercapacitors

Porous carbon is highly regarded as one of the ideal materials for supercapacitor fabrication due to its superior chemical stability, cost-effectiveness and excellent conductivity. Nonetheless, it encounters significant challenges, including limited yield, intricate processing and prolonged processing duration, which greatly hinder its widespread production and utilization. In this study, a simple one-step stripping-etching strategy was proposed to prepare N and Co co-doped porous carbon nanosheets (NCo-C-NS) using Co-ZIF-L as the precursor and the KCl/LiCl mixture as the stripping and etching agent. By varying the calcination temperature, the impact of preparation conditions on the electrochemical performance and morphology of the porous carbon was carefully examined. The results demonstrate that NCo-C-NS-800 exhibit large specific surface area (SSA) of 627.4 m2 g- 1 and achieves the specific capacitance of 201.1 F g- 1 at current density of 1 A g- 1. Additionally, the assembled NCo-C-NS-800//NiO asymmetric supercapacitor (ASC) demonstrates the specific capacitance of 100.06 F g- 1 at 1 A g- 1, energy density of 33.2 Wh kg- 1 at a high power density of 773.4 W kg- 1. The performances of the NCoC-NS-800//NiO ASC under bending conditions were evaluated, confirming the discharge stability and feasibility for practical applications.