Interlayer Spacing Optimization Combined with Zinc-Philic Engineering Fostering Efficient Zn Storage of VCT MXenes for Aqueous Zinc-Ion Batteries.

As emerging cutting-edge energy storage technologies, aqueous zinc-ion batteries (AZIBs) have garnered extensive research attention for its high safety, low cost, abundant raw materials, and, eco-friendliness. Nevertheless, the commercialization of AZIBs is mainly limited by insufficient development of cathode materials. Among potential candidates, MXene-based materials stand out as a promising option for their unique combination of hydrophilicity and conductivity. However, the low Zn kinetics, structural instability, and narrow interlayer spacing of MXenes hinder its practical application. Comprehensively addressing these issues remains a challenge. Herein, different ion pre-embedded VCT MXenes are constructed to tune interlayer spacing, with findings showing NH pre-intercalation is more effective. To accelerate kinetics, it is proposed for the first time a zinc-philic engineering that can effectively reduce Zn migration energy barrier, achieved by decorating the NH -intercalated VCT (NH-VCT) with ZnO nanoparticles. Various analyses and theoretical calculations prove there is a strong coupling effect between ZnO and VCT, which notably boosts reaction kinetics and structural stability. The ZnO-decorated NH-VCT exhibits a high reversible capacity of 256.58 mAh g at 0.1 A g and excellent rate capability (173.07 mAh g at 2 A g). This study pioneers a zinc-philic engineering strategy for the modification of cathode materials in AZIBs.