Strategies for Fabricating High‐Performance Electrochemical Energy‐Storage Devices by MXenes

Abstract Since 2011, MXenes, a family of two‐dimensional transition‐metal carbides, nitrides, and carbonitrides, have been investigated as electrodes, additives, separators, and hosts for energy‐storage devices (ESDs, including supercapacitors and metal‐ion batteries) due to their unique properties. This report focuses on the present technical issues in the field of energy storage and the corresponding solutions involving MXenes. It begins with a series of synthesis approaches (including top‐down and bottom‐up strategies) with a brief description of the structural properties, covering crystal lattice, structural defects, and surface chemistries. In addition, the impact of surface functional groups, composition of transition metals temperature and external pressure on the electrical properties of MXenes is discussed. Then, current issues of ESDs are listed with several MXene‐based solutions, including intercalation, modification of the terminating groups, chemical doping, vacancy engineering and the design of nanocomposites. Finally, the challenges in MXene‐based ESDs are summarised with some potential research directions in the future.