In situ construction of hydrogel coatings on zinc foil surfaces to improve the stability of aqueous zinc-ion batteries

Zinc metal anodes produce side reactions such as dendrite growth and surface corrosion during cycling, leading to premature battery failure. For this reason, we propose an anodic protection strategy for coating sodium carboxymethyl cellulose (CMC) hydrogel material on the surface of zinc foil. This non-conducting 3D porous interconnected network coating acts as a barrier to regulate the flux of zinc ions and electric field distribution, induces zinc to exhibit 3D deposition, and inhibits the growth of dendritic protrusions.The Zn@CMC anode possesses enhanced desolvation capability, which accelerates the rapid transfer of zinc ions, exhibits enhanced kinetics, and inhibits the occurrence of side reactions. The symmetric cell based on CMC hydrogel can be recycled for 1000 h at a current density of 0.5 mA cm⁻² with low voltage hysteresis, and the Zn@CMC//Na-doped VO₂ full cell can maintain a discharge specific capacity of 119 mAh g⁻¹ after 1500 cycles, which is of good practical performance. This study provides a new perspective for the introduction of CMC hydrogel for interfacial modification, which is of reference value for solving interfacial problems.