Insight into the mechanism of nitrogen doping in MXenes with controllable surface chemistry

Abstract

Nitrogen doping emerges as a potent strategy to enhance the electrochemical attributes of two-dimensional MXene materials, recognized for their utility in energy storage solutions. Although advancements have been made, the specific roles of varied doping sites in modifying electrochemical behavior are not fully delineated. This investigation explores nitrogen-doping mechanisms in MXenes with tailored surface chemistries, utilizing a blend of experimental approaches and density functional theory calculations. The distinct roles of nitrogen dopant sites are explored, and the evolution of the electronic structure and stability of the material before and after nitrogen modifications via the urea hydrothermal method are also investigated. The synthesized N-V2CTx-160 MXene electrodes exhibit favorable surface characteristics for energy storage, achieving impressive capacitance properties with a gravimetric capacitance of 592.9 F/g at 2 mV/s in 1 M H2SO4 electrolyte. This work provides a valuable insight for the development of high-performance MXene electrodes for energy storage applications.