MXenes: Advanced materials in potassium ion batteries

MXenes, a new kind of two-dimensional (2 D) materials derived from MAX phases, have shown wide application prospects in metal-ion batteries due to their unique structural and electronic properties. Particularly, the diffusion barrier of K+ on MXenes is very low, indicating that MXenes may have excellent rate performance when applied to potassium ion batterie (PIBs) as anodes. However, pristine MXenes are not suitable to be used as anodes for PIBs due to their low theoretical potassium storage capacity and rapid capacity decline. Here, the potassium storage mechanisms of MXenes are briefly introduced. Besides, this review summarizes the applications of various modified MXenes in PIBs, with emphasis on the relationship between structure and electrochemical performances. Through the analysis of various modification methods, it is hoped that the future development direction of MXenes in PIBs can be seen, so as to provide enlightenment for readers.