Microstructure-resolved modeling and sensitivity analysis of zinc–air batteries

Zinc–air batteries offer high theoretical energy density and material sustainability but are constrained by microstructure-driven nonuniform zinc-anode reactions, transport limitations, and passivation. A multiscale modeling framework, calibrated and evaluated against commercial cells, was developed to quantify how zinc-anode microstructure influences local transport, reaction uniformity, and solid-phase evolution. A one-dimensional electrochemical–transport model combined with Morris screening and Sobol variance decomposition showed that the first-order contributions of three dominant zinc-electrode parameters ( h Zn , 0 , r Zn , 0 , and ɛ Zn , 0 ), together with their pairwise second-order interactions, account for approximately 87.5 % of the output variance among the eight parameters evaluated. This motivated three-dimensional full-cell simulations with localized microstructure-resolved zinc-anode subdomains representing three reconstructed lamellar-type architectures under identical intrinsic parameters. Lamellar 1 and Lamellar 2 delivered higher voltages and longer discharge times than Lamellar 3 and exhibited distinct current-density, hydroxide, zincate, and ZnO distributions. At 100 A m −2 and 99 % depth of discharge, the local current-density coefficients of variation were 0.071, 0.047, and 0.066 for Lamellar 1, Lamellar 2, and Lamellar 3, respectively. Lamellar 1 and Lamellar 2 also exhibited substantially larger local electrolyte clearances, with median wall distances of approximately 9.6 µm, compared with 2.18 µm for Lamellar 3. Despite its lowest effective tortuosity and highest transport-active electrolyte fraction, Lamellar 3 showed inferior discharge performance. The results therefore demonstrate that zinc-anode performance depends on the coupled effects of local electrolyte clearance, transport accessibility, zinc–electrolyte interfacial area, zinc inventory, and reaction localization rather than tortuosity alone. This framework establishes quantitative structure–performance links and highlights microstructural descriptors that can inform the design of structured zinc anodes.