Recent advances and perspectives in MXene-based cathodes for aqueous zinc-ion batteries

Aqueous zinc-ion batteries (AZIBs) show great potential for applications in grid-scale energy storage, given their intrinsic safety, cost effectiveness, environmental friendliness, and impressive electrochemical performance. However, strong electrostatic interactions exist between zinc ions and host materials, and they hinder the development of advanced cathode materials for efficient, rapid, and stable Zn-ion storage. MXenes and their derivatives possess a large interlayer spacing, excellent hydrophilicity, outstanding electronic conductivity, and high redox activity. These materials are considered “rising star” cathode candidates for AZIBs. This comprehensive review discusses recent advances in MXenes as AZIB cathodes from the perspectives of crystal structure, Zn-storage mechanism, surface modification, interlayer engineering, and conductive network design to elucidate the correlations among their composition, structure, and electrochemical performance. This work also outlines the remaining challenges faced by MXenes for aqueous Zn-ion storage, such as the urgent need for improved toxic preparation methods, exploration of potential novel MXene cathodes, and suppression of layered MXene restacking upon cycling, and introduces the prospects of MXene-based cathode materials for high-performance AZIBs.