Protonated interface microenvironment design towards stable Zinc-Metal pouch cells

Abstract

Zinc metal anode is considered to be the major technical shortcoming of building practical aqueous zinc-ion batteries, since random dendrite growth and interfacial chain side reaction would greatly shorten its service life. Herein, a novel protonated diatomaceous earth (DE-ALK)-based artificial interphase is fabricated through a scalable tape-casting strategy. Such protective mechanism not only comes from the physical characteristics but also from the unique protonation interface effect of DE-ALK. As demonstrated, through a strong protonation reaction, the surface charge of DE-ALK shifts from negative to positive of +23.37 mV, result in effectively regulating the anode microenvironment. Benefited from the built-in electrostatic field, the side reactions involving anionic species and HER are suppressed by immobilizing sulfate anions, and the de-solvation of hydrated zinc ions is promoted by weakening the interaction between Zn²⁺ and water, thereby accelerating the reaction kinetics and inhibiting the dendrite growth. As a result, DE-ALK@Zn symmetrical cell achieves an impressive lifespan exceeding 2400 h at 8 mA cm⁻². Moreover, stable Na₂V₆O₁₆·1·5H₂O (NVO)-based pouch cell was further built, which can deliver 269.8 mAh g⁻¹ and a capacity retention of ∼98.6 % after 100 cycles at 0.5 A g⁻¹. This work offers valuable insights for the industrial advancement of aqueous zinc-ion batteries.