Scalable and sustainable slurry processing unlocks practical aqueous zinc batteries

Aqueous zinc-ion batteries (AZIBs) offer a safe, cost-effective, and sustainable solution for large-scale energy storage, yet their deployment is hindered by the difficulty of fabricating thick, high-mass-loading cathodes under sluggish Zn2+ kinetics. Here, we demonstrate a scalable slurry-processing strategy that re-utilizes lithium-ion battery (LIB) manufacturing lines by incorporating acetic acid (HAc) into the cathode slurry, a green additive that eliminates the need for toxic chemicals or dry-room operation while remaining fully compatible with industrial coating lines. Unlike traditional material- or electrolyte-level modifications, this slurry-centered approach uniformly functionalizes particle surfaces during production-scale slurry mixing, promoting proton dehydration and enabling fast, reversible bulk proton storage in commercial γ-MnO2. The process delivers thick cathodes with areal mass loading up to 21.2 mg cm-2 and enables a 26.3 Ah prismatic AZIB that retains nearly 100% capacity after 100 cycles at 1.8C, outperforming state-of-the-art stationary LIBs in power density. At the system level, the HAc-assisted process increases production capacity by 44.2% and reduces system cost from £118.4 to £87.9 kW-1, substantially below the LIB benchmark of £200 kW-1. This work bridges fundamental electrochemistry with industrial manufacturing, establishing a sustainable route toward practical AZIBs.