MXenes for zinc-ion batteries: Synthesis, structural design, and electrochemical applications

Recently, zinc-ion batteries (ZIBs) have garnered significant attention due to their inherent safety, cost-effectiveness, excellent compatibility, and environmental benefits, solidifying their prominence in the rapidly evolving field of battery technologies. Transition metal carbides (MXenes), renowned for their tunable electrical conductivity, pronounced hydrophilicity, and abundant surface functional groups, offer unique mechanical and electrochemical properties that open new pathways for the design and fabrication of ZIBs. Distinct from previous summaries, this review critically establishes the intrinsic correlation between synthesis protocols, defect engineering and electrochemical performance. We comprehensively examine how precise surface chemistry modulation can fundamentally optimize the zincophilicity and reaction kinetics of MXene electrodes. Specifically, the two-dimensional (2D) architecture of MXenes not only increases the surface area available for zinc-ion storage, thereby enhancing battery capacity, but also facilitates efficient ion transport through its layered structure, optimizing charge-discharge performance. With the discovery of novel MAX phases and other related precursors, coupled with emerging fabrication strategies, the field of MXene research is poised for continuous expansion. However, despite the progress made with MXene-based ZIBs, their deployment remains in its infancy. Beyond summarizing current advancements and applications, this review highlights several critical research trajectories that should be emphasized to further advance the application of MXene-based materials as ZIBs electrodes.