A polybromide confiner with selective bromide conduction for high performance aqueous zinc-bromine batteries

•The PBP-BTAB-HB polymer provides selective conduction of bromide over polybromide.•The SP-PBH composite electrode hinders polybromide shuttling in zinc-bromine batteries.•The electrode realizes high coulombic and energy efficiencies of 92% and 74%.•A stable capacity retention of 99.8% is achieved after 1200 cycles.•The high electrochemical performance is preserved at 0 °C.