A review of recent advances in the development of MXene-based nanocomposites as superior anodes for potassium-ion batteries

MXenes have emerged as superior two-dimensional nanomaterials for energy applications by virtue of their high electrical conductivity, surface area, and mechanical strength. Recent works show that MXenes can significantly improve the electrochemical performance of common anode materials for rechargeable batteries due to their unique properties, such as layered structure, excellent electrical conductivity, and hydrophilicity. Among rechargeable batteries, potassium-ion batteries (PIBs) have gained significant attention in recent years as a promising alternative to lithium-ion batteries (LIBs), primarily due to the abundance and low cost of potassium resources. Although PIBs offer many compelling benefits for sustainable energy storage, their development is challenged by the large size of potassium ions, limiting the mechanical and electrochemical stability of the common potassium-host electrodes. Literature identifies the MXene-based nanocomposites as promising anode materials with the potential to enhance the stability of the PIBs. This study reviews the seminal works on the MXene-based nanocomposite anodes for PIBs, including MXene/carbon, MXene/TiO 2 , MXene/sulfides, MXene/selenides and MXene/tellurides. Particularly, the added value of the MXene-based electrodes is highlighted in terms of the synthesis, electrochemical properties, and mechanisms for performance enhancement. • MXene-based nanocomposite anodes for potassium-ion batteries are systematically reviewed. • Preparation routes, key electrochemical metrics, and performance-determining factors are critically compared. • Design principles and underlying mechanisms that boost capacity, rate, and cyclability are unraveled.