Department of Materials Science and Engineering, University of California, Los Angeles, Los Angeles, CA, USA.
Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, USA.
Nat Commun. 2024 Sep 27;15(1):8302. doi: 10.1038/s41467-024-52498-w.
Microbial fuel cells utilize exoelectrogenic microorganisms to directly convert organic matter into electricity, offering a compelling approach for simultaneous power generation and wastewater treatment. However, conventional microbial fuel cells typically require thick biofilms for sufficient metabolic electron production rate, which inevitably compromises mass and charge transport, posing a fundamental tradeoff that limits the achievable power density (<1 mW cm). Herein, we report a concept for redox-mediated microbial flow fuel cells that utilizes artificial redox mediators in a flowing medium to efficiently transfer metabolic electrons from planktonic bacteria to electrodes. This approach effectively overcomes mass and charge transport limitations, substantially reducing internal resistance. The biofilm-free microbial flow fuel cell thus breaks the inherent tradeoff in dense biofilms, resulting in a maximum current density surpassing 40 mA cm and a highest power density exceeding 10 mW cm, approximately one order of magnitude higher than those of state-of-the-art microbial fuel cells.
微生物燃料电池利用放电子微生物将有机物直接转化为电能，为同时进行发电和废水处理提供了一种极具吸引力的方法。然而，传统的微生物燃料电池通常需要厚的生物膜来获得足够的代谢电子产生速率，这不可避免地会影响质量和电荷传输，从而产生了基本的权衡，限制了可实现的功率密度（<1 mW cm）。在此，我们报告了一种基于氧化还原介导的微生物流动燃料电池的概念，该燃料电池在流动介质中利用人工氧化还原介体将代谢电子从浮游细菌高效地转移到电极上。这种方法有效地克服了质量和电荷传输的限制，大幅降低了内阻。因此，无生物膜的微生物流动燃料电池打破了密集生物膜中的固有权衡，最大电流密度超过 40 mA cm，最大功率密度超过 10 mW cm，比最先进的微生物燃料电池高约一个数量级。
