Functional modified separator with high-entropy material for high-performance Zn–I2 batteries

Abstract

The problems of soluble polyiodide shuttling and slow redox kinetics result in irrational cycling stability and restrict the further development of Zn–I₂ batteries. In this paper, self-supporting layers containing high-entropy materials (HEMs) with adsorption–catalytic-conversion integrated functions were applied for the first time for separator modification of Zn–I₂ batteries. Benefiting from the multi-elemental composition of HEMs, the widely distributed d-band centers improve the bonding between metals and molecules to realize the reduced adsorption energies to reactants or intermediates, giving the HEMs substantial highly active sites as adsorption and catalytic centers. This allows the polyiodides to be chemically anchored and catalytically converted by the modified layer once they are formed. The entire iodine conversion reaction proceeds efficiently without polyiodide shuttle and dissolution. As a result, satisfactory cycling stability was achieved. HEMs are proposed as separator modification materials with adsorption–catalytic-conversion synergies, presenting an effective strategy and new inspiration for realizing high-performance Zn–I₂ batteries.