Regulating Zinc Anode Crystallographic Orientation: Unveiling the Role of Electrolyte Additives in Dendrite-Free...

Aqueous zinc-ion batteries (AZIBs) are considered promising next-generation energy storage systems because of their non-flammability, cost-effectiveness, and high theoretical capacity (820 mAh g^-1). However, their practical application is limited by low Coulombic efficiency and poor cycle stability caused by irreversible side reactions and dendritic zinc growth. These issues arise from the anisotropic deposition behavior of commercial zinc foils, driven by their heterogeneous crystallographic orientation, which accelerates 3D protrusion formation. Recent breakthroughs reveal that precisely controlling zinc's crystal orientation can alter deposition thermodynamics via epitaxial growth confinement. This comprehensive review delves into the strategies of electrolyte additive engineering for achieving crystallographically regulated, dendrite-suppressed zinc anodes in AZIBs. The structure-performance relationships of the three key zinc crystallographic planes ((002), (100), (101)) and their deposition dynamics are analyzed. Then, state-of-the-art additives (organic molecules, metal cations, inorganic molecules, ionic liquids) are categorized by facet-selective modulation mechanisms, elucidating their effects on zinc growth orientation and AZIBs performance. Finally, future research directions for dendrite-free zinc deposition are proposed to inspire deeper investigations and accelerate AZIBs development. This review summarizes current progress and offers valuable insights for designing electrolyte additives, crucial for overcoming bottlenecks in AZIBs and enabling their widespread application.