In-situ synchrotron study on the influence of bis-ortoquinone substituents on alkali ion insertion in Fe₂(CAN)₃ and Fe₂(DHBQ)₃ MOFs

Solvent-free metal-quinonoid systems as Fe₂(CAN)₃ (iron-chloranilate) and Fe₂(DHBQ)₃ (iron-dihydroxybenzoquinone) are particularly interesting MOFs due to their high electrochemical activity and the lack of counterions in their inner voids. While both MOFs are composed of hexagonal layers, Fe2(CAN)3 orders in an ABC stacking lending a 2D honeycomb architecture (Figure 1a), whereas Fe2DHBQ3 creates an interpenetrated framework providing a 3D hyperhoneycomb structure (Figure 1b). They mainly differ in their bis-orthoquinone substituents—Cl for Fe₂(CAN)₃ and H for Fe₂(DHBQ)₃— influencing their structural arrangement and potentially their alkali-ion storage mechanisms. This proposal aims to utilize in-situ synchrotron X-ray diffraction during battery cycling to investigate how these substituents impact ion insertion mechanisms, charge transport, and redox stability.