Tailoring MXenes for energy storage: insights into element doping

Element doping can endow MXenes with enhanced electrochemical properties, catalytic performance, and structural characteristics. This extends the arsenal of MXenes and their potential for energy storage applications. This review focuses on the doping mechanism, doping methods and applications of MXenes. Firstly, the mechanism of elemental doping in MXenes is systematically examined based on three factors: lattice substitution, functional substitution, and surface modification. Subsequently, the review provides an exposition of doping strategies and synthesis methods employed in element-doped MXenes. The applications of element-doped MXenes in energy storage, including rechargeable batteries (such as lithium-ion batteries and sodium-ion batteries) and supercapacitors, as well as other fields encompassing electromagnetic shielding, light-heat conversion and water treatment, are also highlighted. Finally, further opportunities for future work and potential applications of element-doped MXenes are presented. This work aims to provide novel insights into how elemental doping can improve the electrochemical performance of MXenes, advancing their development in the field of energy storage.