Microporous Polymer Membranes Tailored for Redox Flow Batteries

Redox flow batteries present unique opportunities for achieving multi-hour electrochemical energy storage at ultra-low cost. Too often, the barrier for implementing them is the unfettered migration redox active species across the ion-transporting membrane, which shorts the battery and exacerbates capacity fade. Here, we advance a new membrane platform with exceptional blocking ability for soluble polysulfides dissolved in flowable catholytes, at minimal impact to ionic conductivity. As a result, Li-S battery performance is dramatically improved, even when anode-protecting LiNO₃ additives are absent.