Recent Advances and Perspectives in MXene-Based Cathodes for Aqueous Zinc-Ion Batteries

Aqueous zinc-ion batteries (AZIBs) hold great promise for grid-scale energy storage applications due to their intrinsic safety, cost effectiveness, environmental friendliness, and impressive electrochemical performance. However, the strong electrostatic interactions between zinc ions and host materials place obstacles in the development of advanced cathode materials that can accommodate the efficient, rapid, and stable Zn-ion storage. MXenes and their derivatives, which feature large interlayer spacing, excellent hydrophilicity, outstanding electronic conductivity, and high redox activity, are considered as the “rising star” cathode candidates for AZIBs. Herein, we comprehensively review the recent advances in MXenes as cathodes for AZIBs from the perspectives of crystal structures, Zn-storage mechanisms, surface modification, interlayer engineering, and conductive network design to elucidate the correlations among composition, structure, and electrochemical performance. Then, we outline the remaining challenges facing MXenes for aqueous Zn-ion storage such as the urgent need for improvement of the toxic preparation methods, the exploration of potential novel MXene cathodes, and the suppression of restacking of layered MXenes upon cycling, and foresee the bright prospects of MXene-based cathode materials for high-performance AZIBs.