N-Doped Two-Dimensional Carbon Nanosheets with Micropore-Dominant Porosity for High-Performance Supercapacitors

Abstract

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