Space-confined catalysis of iodine with oxygen vacancy-driven nanopump for durable aqueous zinc-iodine batteries

Aqueous zinc-iodine (Zn-I₂) batteries represent a promising solution for long-duration energy storage; however, the challenge of polyiodide shuttling remains a critical limitation. To address this issue, we engineered an oxygen vacancy-driven nanopump for I₂ molecules based on a two-dimensional van der Waals heterostructure, comprising oxygen vacancy-rich Ti-Nb bimetallic oxide nanosheets sandwiched between carbon layers (V_o-TNO@C). The oxygen vacancies in V_o-TNO@C strongly interact with I₂, facilitating effective capture and confinement of I₂ within the interlayer gap. The confined I₂ is catalytically transformed in situ by the oxygen vacancies, altering the reaction pathway from the conventional approach (I₂ → I₃⁻ → I⁻) to a more efficient way (I₂ → I⁻). This confined catalysis significantly accelerates conversion kinetics and suppresses polyiodide formation, resulting in shuttle-free Zn-I₂ batteries with an exceptional lifespan exceeding 70,000 cycles.