Cavity-Enabled Supramolecular Regulation of Capacitive–Redox Bromine Electrochemistry in Zinc–Bromine Batteries

The intrinsic trade-offs between high-rate capacitive processes and high-capacity redox reactions fundamentally limit advanced electrochemical energy storage. Here, we transcend this paradigm by introducing cavity-enabled supramolecular microreactors as a versatile platform for synergistic bromine capacitive-redox electrochemistry. These microreactors exhibit voltage-responsive dual functions, operating as a high-capacity ion-sequestration matrix at low voltages governed by their tailored electrostatic cavity landscape, and dynamically switching to an anchoring and conversion-promoting center at high voltages via spatially confined noncovalent interactions distinct from conventional bonding. Deployed in an aqueous zinc-bromine battery, this strategy delivers a specific capacity of 481.8 mAh g−1 at 0.83 A g−1 and retains 89.4% of its capacity after 1500 cycles at a specific current of 8.3 A g−1. Our work transcends the conventional material design philosophy, establishing a general approach for breaking the intrinsic limits of electrode materials through molecular-scale ion regulation. Aqueous zinc-bromine batteries face a trade-off between capacitive power and redox capacity. Here, authors design cavity enabled supramolecular that dynamically switch from ion storage at low voltages to polybromide stabilization at high voltages, delivering high capacity, power and cycling durability.