Rechargeable zinc–air batteries, having high energy densities and cost-effectiveness, are important environmentally-benign energy storage solutions. Here we developed a facile strategy for fabricating a nanoporous alkaline-exchange electrolyte membrane from natural cellulose nanofibres, exhibiting high ionic-conductivity and water retention as well as high bending flexibility. These advantages render the membrane a promising solid-state electrolyte for rechargeable zinc–air batteries in lightweight and flexible electronic applications.
