Flake size-dependent zinc deposition on Ti3C2T MXene electrodes

• Controlling MXene flake dimensions provides a practical and scalable route to engineer dendrite-suppressing current collectors for safer, longer-lasting aqueous Zn-ion batteries • Increasing the lateral size of Ti₃C₂Tₓ flakes promotes epitaxial-like Zn growth along the stable (002) plane, leading to smoother and dendrite-free zinc layers • Large-flake Ti₃C₂Tₓ electrodes enable stable Zn plating/stripping over 600 hours, while smaller flakes lead to irregular, dendritic deposits and early failure The growing demand for safe and sustainable energy storage systems (ESS) highlights the limitations of lithium-ion batteries (LIBs), particularly regarding safety risks and resource scarcity. Zinc-ion batteries (ZIBs) are an attractive alternative due to their intrinsic safety, low cost, and compatibility with aqueous electrolytes, but their performance is hindered by zinc dendrite formation. MXenes, and especially Ti₃C₂Tₓ, have emerged as promising current collectors because of their high conductivity, hydrophilicity, and favorable lattice matching with Zn. Here, we investigate the influence of Ti₃C₂Tₓ flake size on Zn deposition and cycling stability. Free-standing MXene electrodes with controlled flake dimensions were fabricated and evaluated by electrochemical and morphological analyses. Results show that larger flakes promote epitaxial-like Zn growth along the stable (002) plane, leading to smoother deposits, reduced dendrite formation, and improved reversibility. Electrodes with micrometric flakes exhibited stable plating/stripping for over 600 hours with a Coulombic efficiency of ∼91%, while nanometric flakes resulted in irregular, dendrite-prone growth and rapid cell failure. These findings demonstrate that tailoring MXene flake size provides a simple yet effective route to extend the lifetime of aqueous Zn batteries, offering practical guidelines for designing safer and more durable energy storage systems.