A superhydrophilic battery sponge with positive and negative electrodes for the demulsification of oil-in-water emulsions

•The battery sponge possesses a battery structure and superhydrophilic properties.•The battery sponge can efficiently purify various o/w emulsions.•The battery sponge can repeatedly disrupt the stability of emulsions.•The battery sponge possesses high recyclability and stability.•Mechanisms for one/mixed charged superhydrophilic sponge are analyzed.