Revisiting Interfacial Desolvation for Zn Powder Anodes in 30 Ah Practical Prismatic Zn-Ion Batteries

Zn powder anodes combine high surface area, mechanical flexibility, and compatibility with slurry-based fabrication, making them highly attractive for industrial-scale aqueous Zn-ion batteries (ZIBs). Despite these advantages, the core challenge lies in its inherently high interfacial reactivity, which accelerates side reactions such as hydrogen evolution and uncontrolled dendrite growth, ultimately destabilizing the solid-liquid interface. This work identifies a kinetic origin by splitting interfacial desolvation into Zn^{2 +} solvation shell removal and surface desorption, finding conventional electrolytes fail to regulate the latter, especially for defective, porous Zn powders. Polyethylene glycol (PEG) as a cosolvent in Zn(ClO₄)₂ electrolytes modifies desolvation and Zn^{2 +} deposition, reducing reaction kinetics and suppressing side reactions. The optimized electrolyte enables a Zn||Cu cell to cycle over 1600 times with 8.9 mV overpotential. A 1 Ah Zn-P||VO₂ pouch cell retains 387 mAh g^{- 1} after 900 cycles, and a 30 Ah prismatic cell confirms scalability. This clarifies Zn powder bottlenecks and offers an electrolyte-interface co-design framework.