Multielectron Transfer in Halogen Batteries

Abstract

Multielectron transfer in halogen batteries is a promising solution in pursuing high-energy-density and affordable energy storage systems. Interest in rich chemistries derived from unique valence electron structures of halogens is surging in electrode material design. However, deploying multielectron transfer chemistry comes with challenges, including limited redox reactivity and degrees of electrochemical irreversibility, which contribute to poor charging and cycling. To address these challenges, researchers explore physical/chemical strategies to activate high valence reactions and more electron transfer numbers and fix unstable valence state species through electrolyte and electrode regulation. This Concept presents the basic understanding of multielectron transfer electrochemistry concerning theoretical energy capabilities and electronic configuration evolutions. We divide multielectron transfer into two types: single and multi-redox centers, providing an overview of the current development of multielectron transfer and hoping it will spur more intensive efforts towards a diverse energy future.