Membrane-less cloth cathode assembly (CCA) for scalable microbial fuel cells

• Published in: Biosensors & bioelectronics 2009-08, Vol.24 (12), p.3652-3656
• Main Authors: Zhuang, Li, Zhou, Shungui, Wang, Yueqiang, Liu, Chengshuai, Geng, Shu
• Format: Article
• Language: English
• Subjects: Assembly; Biochemical fuel cells; Bioelectric Energy Sources - microbiology; Biological and medical sciences; Biotechnology; Cathodes; Cloth; Cloth cathode assembly; Conductive catalytic coatings; Conductive paint; Electric power generation; Electro-osmotic drag; Electrochemistry - instrumentation; Electrodes; Electronics - instrumentation; Fundamental and applied biological sciences. Psychology; Membranes, Artificial; Microbial fuel cell; Microorganisms; Nickel; Paints; Protective coatings
• ISSN: 0956-5663; 1873-4235
• DOI: 10.1016/j.bios.2009.05.032

One of the main challenges for scaling up microbial fuel cell (MFC) technologies is developing low-cost cathode architectures that can generate high power output. This study developed a simple method to convert non-conductive material (canvas cloth) into an electrically conductive and catalytically active cloth cathode assembly (CCA) in one step. The membrane-less CCA was simply constructed by coating the cloth with conductive paint (nickel-based or graphite-based) and non-precious metal catalyst (MnO 2). Under the fed-batch mode, the tubular air-chamber MFCs equipped with Ni-CCA and graphite-CCA generated the maximum power densities of 86.03 and 24.67 mW m −2 (normalized to the projected cathode surface area), or 9.87 and 2.83 W m −3 (normalized to the reactor liquid volume), respectively. The higher power output of Ni-CCA-MFC was associated with the lower volume resistivity of Ni-CCA (1.35 × 10 −2 Ω cm) than that of graphite-CCA (225 × 10 −2 Ω cm). At an external resistance of 100 Ω, Ni-CCA-MFC and graphite-CCA-MFC removed approximately 95% COD in brewery wastewater within 13 and 18 d, and achieved coulombic efficiencies of 30.2% and 19.5%, respectively. The accumulated net water loss through the cloth by electro-osmotic drag exhibited a linear correlation ( R 2 = 0.999) with produced coulombs. With a comparable power production, such CCAs only cost less than 5% of the previously reported membrane cathode assembly. The new cathode configuration here is a mechanically durable, economical system for MFC scalability.