| Abstract Scope |
Fluoride- and chloride ion batteries are attractive energy storage concepts analogous to lithium-ion batteries but feature an inverted paradigm where anions are the principal charge carriers. Insertion hosts and solid electrolytes that can reversibly insert and diffuse halide ions at room temperature are exceedingly sparse. I will discuss design principles underpinning halide-ion insertion based on multi-center synergies between p- and d-block centers. Considering FeSb2O4 as a model system, separation of the redox center from the p-block coordination site alleviates structural strain by enabling compensatory contraction and expansion of FeO6 and SbO3 polyhedra, respectively. Specifically, stereoactive p-block electron lone pairs play a critical role in weakening anion-lattice interactions, thereby enabling reversible fluoride-ion diffusion across microns. I will further discuss strategies for systematic modulation of anion-lattice interactions by tuning p- and d-block centers, which affords an expanded palette of anion insertion hosts. |