Perovskite Cathodes for Aqueous and Organic Iodine Batteries Operating Under One and Two Electrons Redox Modes

Abstract Although conversion‐type iodine‐based batteries are considered promising for energy storage systems, stable electrode materials are scarce, especially for high‐performance multi‐electron reactions. The use of tin‐based iodine‐rich 2D Dion–Jacobson (DJ) ODASnI₄ (ODA: 1,8‐octanediamine) perovskite materials as cathode materials for iodine‐based batteries is suggested. As a proof of concept, organic lithium‐perovskite and aqueous zinc‐perovskite batteries are fabricated and they can be operated based on the conventional one‐electron and advanced two‐electron transfer modes. The active elemental iodine in the perovskite cathode provides capacity through a reversible I⁻/I⁺ redox pair conversion at full depth, and the rapid electron injection/extraction leads to excellent reaction kinetics. Consequently, high discharge plateaus (1.71 V vs Zn²⁺/Zn; 3.41 V vs Li⁺/Li), large capacity (421 mAh g⁻¹_I), and a low decay rate (1.74 mV mAh⁻¹ g⁻¹_I) are achieved for lithium and zinc ion batteries, respectively. This study demonstrates the promising potential of perovskite materials for high‐performance metal‐iodine batteries. Their reactions based on the two‐electron transfer mechanism shed light on similar battery systems aiming for decent operational stability and high energy density.