No abstract

Summary Sediment microbial fuel cells (SMFCs) can covert the biomass and organic matters in sediments into electricity. SMFC stack is an essential way for the application of SMFCs. The unit distance and number will be crucial for SMFC stacks applied in practical environments. This study showed that the power density of individual SMFC increased with the unit distance when compared with SMFCs with a small distance. For hydraulically connected serial stacks, increasing unit distance from 2 to 28 cm decreased the potential loss from 50.4% to 11.3%, but the power output did not increase with either unit distance or number of units due to higher internal resistance and electrode reversal. For hydraulically connected parallel stacks, increasing unit number from one to three multiplied the power output but no further power increase was observed with four and five units, indicating an optimal unit number (OUN) in parallel stacks due to ion conduction. Similar performance was shown when using SMFC stacks to power a light‐emitting diode and an environmental sensor. The results provide important information for improving the power and cost‐effectiveness of SMFC stacks.