A terracotta bio-battery

► Terracotta pots were converted to simple, air-cathode bio-batteries. ► A peak power of 1.06 mW was produced with non-Pt catalyzed cathode. ► Extract of dried grass plus common salt supported current production. ► Microbial community on the anode can survive dehydration and starvation. ► These batteries can be used for off grid lighting in poor communities.