This paper reports a computer-led search for new cathode materials for rechargeable aqueous zinc‑ion batteries (RAZIBs). These batteries use water‑based electrolytes and zinc metal. They are safer and cheaper than lithium‑ion cells, but current cathodes lose capacity when charged and discharged at speeds needed for grid storage (rates below C/2). The authors aimed to find cathode materials that keep working in water and give useful voltages and capacity.

The team screened more than 2,000 materials that have already been made in a lab. The list included oxides, chalcogenides, Prussian blue analogues (a class of open framework compounds), and polyanion compounds. They took the data from the Materials Project database (version 2025.09.25). For each material they checked three things by calculation: whether zinc ions can move through the crystal (they looked for connected Zn2+ paths), whether the material is stable in water under the battery’s voltage and pH conditions (using computed Pourbaix diagrams and electrochemical decomposition energies), and whether the transition metal in the material can change oxidation state in a way that allows energy to be stored and released.

At a basic level, a zinc‑ion cathode must admit and release Zn2+ ions without falling apart or dissolving in the aqueous electrolyte. The authors used molecular dynamics simulations (computer simulations of atomic motion) to calculate the zinc intercalation potentials — the voltage at which zinc moves into or out of the material. They found that two factors control the calculated voltage: the oxidation state that the transition metal can reach during cycling, and the local environment (coordination) of the zinc ion once it is inside the structure. These findings point to design rules for making cathodes with higher operating voltages.

From the initial pool, 131 materials passed the structural, chemical and aqueous‑stability filters and had their Zn2+ intercalation potentials calculated. The authors then highlighted 10 previously unexplored materials as top candidates for experiments. These are MnBePO5, α‑FePO4, β‑FePO4, KV2PO8, SrV2O6, Mo2P2O11, Cs2Mo4O13, K3Fe5(PO4)6, CaFe3P3O13, and SrFe3P3O13. The chosen materials stand out in the study because they combine high calculated Zn2+ (de)intercalation potential, electrochemical stability in water, and favorable theoretical gravimetric capacity and energy density.