Anti-passivation of commercial Zn anodes by self-deprotonation additives for aqueous Zn metal batteries

Aqueous Zn metal batteries (AZBs) hold significant promise for grid-level energy storage, yet their commercial viability is hindered by surface passivation of Zn anodes in humid air and aqueous electrolytes. Aiming at this issue, we present a novel self-deprotonation electrolyte additive, pyridinium (PyH⁺), which resolves passivation issues through gradually releasing protons and creating a H₂O-lean microenvironment through adsorption. With the PyH⁺ additive, commercial Zn anodes without pretreatment achieve lifespans exceeding 4600 h in Zn//Zn coin cells and 800 h in 25 cm² Zn//Zn pouch cells at 1 mA cm⁻², compared to only 360 h and 100 h in PyH⁺-free electrolyte, respectively. Attractively, we demonstrate that such self-deprotonation strategy can be extended to other protonated N-containing heterocyclic compounds, which display universial anti-passivation effects as electrolyte additives. This work provides a promising approach for the anti-passivation of commercial Zn anodes to achieve long-lasting and large-scale AZBs.