Proton conductive polyoxometalates.

Polyoxometalates (POMs), also known as transition metal‑oxygen clusters deliver unique physical and chemical properties such as low effective surface charge density, high thermal stability, and multi-electron acceptance, making them suitable for proton conductors. In recent years, proton conductive POMs have achieved significant progress in high performance (>10−2 S/cm) comparable to conventional materials through structural regulation strategies. At the same time, the veiled conduction mechanism has been elucidated by structural analysis and characterization. In this review, the research of POMs (Keggin-type, Dawson-type, composite materials) in proton conduction is reviewed mainly from the design strategy, proton conductivity and mechanism, structure-function relationship, and application, finally with a detailed discussion of challenges and prospects. This review will provide more inspiration for exploring and applying proton-conducting POM materials. Polyoxometalates (POMs) have low effective surface charge density, high thermal stability, electron acceptance ability, and discrete mobile ion components, making them particularly suitable as proton conductors. This article reviews the recent advances in this field, including Keggin-type POMs, Dawson-type POMs, organic-graded POMs, composites, and others. The design strategy, the relationship between structure and proton conductivity, and the future development trend of POMs are discussed. [Display omitted] • We provide a detailed elaboration on proton conducting POMs. • The design strategy, proton conductivity and mechanism, structure-function relationship, and application are summarized. • The review provides the prospects and challenges of proton conducting POMs. • The review would inspire development of more advanced proton conducting materials. [ABSTRACT FROM AUTHOR]