Work

High‐Performance Zinc Halogen Aqueous Battery Exploiting [BrCl 2 ] − Storage in Ketjenblack by Reconstructing Electrolyte Structure

Year: 2025

Type: article

Abstract: Halogen redox couples offer distinct merits due to high redox potential and low cost, but they usually suffer from poor reversibility. Here, we report highly reversible [Br 2 Cl] − /Br − and [BrCl 2 ] − /Cl − redox couples via harnessing interhalogen chemistry within nanoporous Ketjenblack (KB) carbon as a host for zinc‐based aqueous batteries. The tunable halogen reactions are facilitated by controllable coordinating chemistry of [ZnCl 4‐ x Br x ] 2− in a hydrated deep eutectic solvent electrolyte comprising ZnCl 2 , ZnBr 2 , and choline chloride (C 5 H 14 ClNO). In an optimized electrolyte, the KB electrode delivers a high discharge capacity of 535 mAh g KB −1 or 214 mAh g −1 when the stored [BrCl 2 ] − is counted at 100 mA g −1 , with an average discharge voltage of ~1.6 V, and a record high energy density of 788 Wh kg KB −1 or 315 Wh kg −1 , when considering the mass of [BrCl 2 ] − as well. Benefiting from the interhalogen coordination chemistry and KB pore host, the pouch cell delivers an areal capacity of 2.3 mAh cm −2 at 0.5 mA cm −2 , storing an energy density of ~80 Wh kg −1 based on the mass of both electrodes. This work offers a new strategy to enhance the reversibility of static aqueous halogen batteries for energy storage applications.

Source: Angewandte Chemie International Edition

DOI: 10.1002/anie.202421905