One step synthesis of ultrathin 2D carbon nanosheets for high-performance supercapacitors

Abstract

Two-dimensional (2D) porous carbon materials have become promising candidates due to their high content of exposed active sites and convenient ion transport pathways compared with traditional porous carbon materials. However, they suffer from the drawbacks of thick nanosheets and complicated synthesis process, which results in unsatisfactory performance and limits their practical application. So far, the key challenge is to synthesize ultrathin 2D carbon nanosheets by a green, up-scalable and low-cost route. Herein, we report a facile approach to prepare two-dimensional ultrathin porous carbon nanosheets. The approach we propose applies self-activation and a self-template one-pot method without any additive. Compared with the 50 nm to 200 nm thickness nanosheets from previous work, the prepared 2D porous carbon nanosheets present impressively ultrathin (approximately 1.7 nm thick) nanosheets and reasonable pore size distribution. The materials demonstrate higher specific capacitances, more excellent rate capability and outstanding cycling stability compared with those in previous reports. We believe that the work we report provides a promising electrode candidate and a facile strategy to synthesize porous carbon electrode materials with ultrathin nanosheets for energy storage. Ultrathin nanosheets, the high performance supercapacitor electrode, were synthesized by pyrolysis of potassium benzoate without any additives in one step. • A facile strategy to synthesize 2D ultrathin carbon nanosheets (UPCNs) is proposed. • The as-prepared 2D porous carbon nanosheets are impressively ultrathin (approximately 1.7 nm thick). • The optimized UPCNs-700 exhibits excellent electrochemistry performance. • A promising candidate electrode material for supercapacitors are provided.