Intermittent energy harvesting improves sediment microbial fuel cell performance

Abstract

This study reports on the response of sediment microbial fuel cells to intermittent and continuous energy harvesting. Ceramic separators made from terracotta and terracotta with 20% bentonite were employed. The aim of this study was to investigate whether intermittent energy harvesting with a 20% duty cycle would provide higher power density than continuous loading. Results show that continuous energy harvesting provides more average power over a 1 hour period. Intermittent energy harvesting showed relatively more power, with the 20% duty cycle providing 32%-46% of the power of a continuous cycle. Current densities during intermittent cycles were 2.6 to 4 fold higher than during continuous operation. Performance tapered off over the course of the experi-ment for both strategies. Cells using separators with bentonite performed better during intermittent harvesting while terracotta cells outperformed during continuous operation. Cathode overpotentials were identified as the rate limiting factor during operation.