N‑Doped\nTwo-Dimensional Carbon Nanosheets with\nMicropore-Dominant Porosity for High-Performance Supercapacitors

Abstract

N-doped two-dimensional (2D) porous carbon nanosheets\n(PCNs) have\nbeen developed for high-performance supercapacitors (SCs) through\nchemical crosslinking of biomass shell and γ-glutamic acid followed\nby pyrolysis and activation. The C and N recomposition and pore formation\nprocesses occur within the shell/γ-glutamic acid composite during\npyrolysis. The enormous specific surface area of 2393 m² g^–1, unique 2D nanosheet, and rich microporous\nstructure are only a few of the benefits of an optimized PCNs material.\nThe rich oxygen/nitrogen functional groups and 2D nanosheet structure\nendow the materials with super hydrophilicity, and also provide extra\npseudocapacitance. With these added structural advantages and the\ncomponent synergy, the PCNs show superior performance for which the\nspecific capacitance is 321 F g^–1, and only with\na 7% capacitance loss after 13,000 cycles in a three-electrode system.\nFurthermore, a PCNs-based symmetric SC displays a high specific energy\nof 9.7 W h kg^–1.