Bioelectrochemical systems hold potential for both conversion of electricity into chemicals through microbial electrosynthesis (MES) and the provision of electrical power by oxidation of organics using microbial fuel cells (MFCs). This study provides a proof of concept for a microbial rechargeable battery (MRB) allowing storage of electricity by combining MES and a MFC in one system. Hexacyanoferrate(II/III) was used as counter redox couple. Duplicate runs showed stable performance over 15 days, with acetate being the main energy carrier. An energy density of around 0.1 kWh/m3 (normalized to anode electrolyte volume) was achieved at a full cycle energy efficiency of 30-40%, with a nominal power output during discharge of 190 W/m3 (normalized to anode volume). With this study, we show a new potential application area for bioelectrochemical systems as a future local energy storage device.