Synergistic combination of N/P dual-doped activated carbon with redox-active electrolyte for high performance supercapacitors

Heteroatom-doping in carbon is an effective strategy to boost capacitance through additional redox reactions. Furthermore, the introduction of heteroatoms to the carbon lattice, decreases its charge transfer resistance with enhanced wettability. Herein, a synergistic interaction of dual-doped [nitrogen (N) and phosphorus (P)] activated carbon (AC-NP) with redox-mediated electrolyte is investigated. Pyridinic and pyrrolic functionalities due to N-doping act as a source of Lewis base and result in augmentation of H+ adsorption. In addition, because P is larger and less electronegative than carbon, this raises the number of active sites for adsorption of ions and amplifies the electron delocalization at the carbon lattice. Further, high redox activity of HQ in H2SO4 triggers intramolecular hydrogen bonding between N and quinone that enhances the ion transfer through an inner sphere mechanism. Consequently, the synergistic interaction of N with quinone raises the charge storage ability of the assembled cell (AC-NP||AC-NP) by 4.85-fold with a phenomenal increase in specific energy (41.5 Wh kg-1 @ 540.32 W kg- 1). This work demonstrates an effective strategy to raise the specific energy of carbonaceous electrode materials by utilizing a synergistic interplay between N, P functionalities and redox-mediated electrolytes.

Automated summary

This study presents an effective strategy to enhance the specific energy of carbonaceous electrode materials through the synergistic interaction of N, P functionalities, and redox-mediated electrolytes.