Starting from Galvani bioelectrochemistry is dealing mainly with voltage generated by ion transport through ion-selective biological membranes. Contrary to this, starting from Volta, the voltage generated in electrochemical cells is based on electron transport and redox reactions on two electrodes separated by an ion-conducting electrolyte. Here we combine these ideas and present the first battery where a metal foil is acting as an electron-selective membrane. Without traditional electrodes, this biomimetic battery in a flow-through modification has several obvious advantages, including several times smaller weight, size, and cost. It will also be more environmentally benign than existing vanadium-based redox-flow batteries.