Designing physico-chemisorptive cations to stabilize aqueous zinc-iodine batteries

초록

Electrolyte additives have been widely explored to mitigate the key challenges in aqueous zinc-iodine batteries (AZIBs), such as self-discharge, hydrogen evolution, and dendritic zinc growth. However, the lack of rational selection criteria and the reliance on case-specific interpretations have hindered a coherent understanding of additive behavior. Here, we present a descriptor-guided, generalizable design concept for physico-chemisorptive cations (PCCs) that strongly bind polyiodides and stably anchor on carbon and zinc surfaces. Central to this design, the soft cationic core enables strong chemisorption with polyiodides, while the long alkyl chain promotes stable physisorption on the electrodes. As a proof of concept, 1-butyl-3-methylimidazolium, featuring an aromatic ring and a butyl side chain, was employed as a representative PCC-enabling AZIBs to achieve outstanding cycling stability (>17,500 cycles) under demanding conditions (5 mAh cm(-2), 60 mA cm(-2)) with a high average coulombic efficiency (>98%). These findings establish PCC-based interfacial engineering as a promising strategy for advancing aqueous zinc-halogen batteries through molecularly regulated interfacial stabilization.

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