Trimetallic Atom‐Doped Functional Carbon Catalyst Enables Fast Redox Kinetics and Durable Cyclic Stability of Zinc‐Iodine Batteries

Abstract

Active iodine dissolution and polyiodide shuttle are two major obstacles hindering the application of zinc‐iodine batteries (ZIBs). Designing functional carriers with strong physisorption/chemisorption capability, abundant active sites, and high catalytic activity for iodine redox reaction kinetics, is considered an effective strategy to solve the current problems of ZIBs. In this work, Fe, Co, Ni‐doping porous carbon (FeCoNi) is comprehensively investigated as carrier material to prepare the iodine‐loading cathode of FeCoNi@I2. On the basis of experimental tests and theoretical calculations, the introduction of FeCoNi trimetallic atoms effectively regulates the electronic structure, charge distribution, active sites, and electronic conductivity of porous carbon substrate, promoting the iodine conversion reaction kinetics as well as chemisorption capability for iodine species, which is conducive to inhibit the polyiodide shuttle and active iodine dissolution. As expected, Zn//FeCoNi@I2 batteries exhibit high specific capacity and strong self‐discharge resistance capability, and the reversible capacity of FeCoNi@I2 cathode stabilizes at 108.8 mAh g−1 after 13000 cycles at 1 A g−1, and 94.7 mAh g−1 after 14000 cycles at 3 A g−1. This work will open new horizons for the structural design of catalyst‐type carrier materials for durable ZIBs, and facilitate the application of trimetallic atom‐doped porous carbon in high‐performance secondary batteries.