A rationally designed hetero-assembly of 2D/2D Nitrogen-doped MXene/Graphene via supercritical fluid processing for high energy durable supercapacitors

To enhance high-rate cycle stability and energy density of supercapacitors, highly effective electrode materials are essential. Two-dimensional (2D) materials are anticipated to rank among the most remarkable compounds for use in the energy sector. The expected ability to store energy in two 2D materials, reduced graphene oxide (rGO) and Nb2C MXene through making a hetero-assembly, is demonstrated in this research for the first time by dual N doping on both lattices using the supercritical fluid processing method. To the best of our knowledge, the supercritical fluid synthesis of the 2D/2D MXene-based hetero-assembly is unique and distinctive. The high charge storage ability of N-(Nb2C/rGO) sites and the typical reaction kinetics all add to the outstanding electrochemical performance of the engineered hetero-assembly through this unique synthetic procedure. The N-(Nb2C/rGO) consequently displays exceptional electrochemical performance with a high specific capacitance of 816 F/g at a current density of 1 A/g and an admirable energy density of 29 Wh/kg in aqueous H2SO4 electrolyte, and 33 Wh/ kg in non-aqueous TEABF(4)/ACN electrolyte. Furthermore, after 100,000 rounds of charging and discharging, the capacitance retention is still keeping 100% of the initial capacitance in quasi-solid-state PVA/H2SO4 based electrolyte. Herewith this current study offers insights into the modulation of energy storage ability and the logical design of high-performance N-dual doped MXene/rGO based hetero-assembly for electrode material from aqueous to non-aqueous to quasi-solid-state supercapacitors.

Automated summary

This research demonstrates the ability to store energy in a hetero-assembly of two-dimensional materials, reduced graphene oxide (rGO) and Nb2C MXene, through dual N doping on both lattices using the supercritical fluid processing method. The engineered hetero-assembly, N-(Nb2C/rGO), exhibits outstanding electrochemical performance with high specific capacitance and admirable energy density in aqueous and non-aqueous electrolytes. Additionally, the capacitance retention remains close to 100% after multiple cycles of charging and discharging in a quasi-solid-state electrolyte. This study provides insights into the modulation of energy storage ability and the design of high-performance electrode materials for supercapacitors.