Ti₂CT_x MXene Cathode Host for Enhanced Zinc‐Bromine Battery Performance

Abstract

Aqueous zinc‐bromine batteries represent a promising large‐scale energy storage system, yet generally suffer from the dissolution of polybromides in the cathode. Currently, various nonpolar carbon materials are employed as hosts for the bromine cathode. Still, they typically exhibit weak adsorption capabilities toward polybromides. Here, a highly conductive Ti2CTx MXene synthesized through an eco‐friendly molten salt method is reported, serving as an ideal bromine cathode host material for the first time. Ti2CTx MXene shows strong chemisorptive capability to soluble polybromide species and can effectively immobilize them for enhanced coulombic efficiency and prolong cycling life of zinc‐bromine batteries. Additionally, Ti2CTx MXene enhances the reaction kinetics of the bromine cathode. Benefiting from the synergistic polybromide adsorption and catalysis effects of Ti2CTx, the dual‐plating zinc‐bromine batteries exhibit good cycle stability, with a capacity retention of 87% after 3000 cycles, outperforming traditional carbon host which fail after 2300 cycles. Meanwhile, Ti2CTx achieves a much lower polarization voltage of only 84 mV, significantly less than 240 mV observed with carbon hosts. This research highlights the potential of developing host materials with polybromide chemisorptive properties to advance the performance of zinc‐bromine batteries.