Constructing MXene hydrogels and aerogels for rechargeable supercapacitors and batteries

Two-dimensional (2D) MXenes have attracted tremendous attention in rechargeable supercapacitors and batteries due to their unique 2D structure, good conductivity, adjustable components, and abundant surface functional groups. However, MXene sheets suffer from sheet restacking and aggregation due to the strong van der Waals interactions between adjacent sheets. Constructing 3D porous architectures (e.g., hydrogels and aerogels) from 2D MXene sheets and the corresponding MXene composites can effectively inhibit nanosheet restacking and facilitate the electrochemical reaction kinetics in rechargeable supercapacitors and batteries. This review summarizes the synthesis strategy of MXene hydrogels and aerogels and discusses their recent development in rechargeable supercapacitors and batteries. Furthermore, the challenges and perspectives of MXene hydrogels and aerogels in supercapacitors and batteries are put forward. Finally, we believe this review will provide new insight into the fundamental synthesis, structure, and applications of MXene hydrogels and aerogels and promote the future development of MXene hydrogels and aerogels.