Vermiculite-coated Zn anodes for suppressed dendrite growth and side reactions towards long-life aqueous Zn-I2 batteries

Zn-ion batteries (ZIBs) have attracted considerable attention as promising energy storage systems owing to their natural abundance, low standard electrode potential (-0.76 V), and high theoretical capacity (820 mAh g − 1 ). Nevertheless, their practical application is severely hindered by Zn dendrite growth, hydrogen evolution, and electrode passivation. To address these challenges, we constructed a Zn-based vermiculite coating on Zn anodes (Ver@Zn), which reduces the direct exposure of Zn to the electrolyte and suppresses side reactions and passivation layer formation. Owing to its unique Zn 2+ interlayer channels and electronic insulating properties, the vermiculite coating facilitates uniform Zn 2+ migration and nucleation, thereby enabling homogeneous Zn deposition. As a result, the modified Zn anode exhibited enhanced corrosion resistance and higher Coulombic efficiency (CE). The vermiculite particle with optimized size (45–61 μm) yielded the best cycling stability, with a symmetric cell lifetime of up to 1700 h, far exceeding that of bare Zn. Furthermore, the Ver@Zn anode delivered superior performance in Zn/I 2 full cells, maintaining high specific capacity, rate capability, and long-term cycling stability (98% capacity retention after 3000 cycles) with CE of 99.8%. This work demonstrates an effective surface engineering strategy for advancing high-performance aqueous Zn iodine battery.