A proof-of-concept rechargeable battery driven by bacterial processes offers potential as a local energy storage device. The battery combines microbial electrosynthesis for conversion of electricity into acetate with microbial fuel cells which convert the acetate back into electric power.

Schematic of the proof of concept microbial rechargeable battery. Image source: ACSResearchers from Wageningen University and Wetsus in the Netherlands successfully charged the battery over a 16-hour period and discharged it over the next 8 hours, mimicking the day-night pattern typical for solar energy production. This cycle was repeated 15 times in as many days.

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 further optimization, the researchers say the energy density of the microbial battery could be competitive with conventional technologies, such as lithium-ion batteries.