Materials for Microbial Fuel Cells

Table 9.1. Comparison of anode materials for microbial fuel cells. ...

Carbon nanotube/polyaniline composite as anode material for microbial fuel cells. Journal of Power Sources, 170, 79-84. 

Y. Qiao, C.M. Li, S.-J. Bao and Q.-L. Bao, Carbon nanotube/polyaniline composite as anode material for microbial fuel cells, /. Power Sources 170,2007,79-84. 

Electrode materials play an important role in the performance (power output) and cost of bacterial fuel cells. This problem was the topic of two review papers. In a review by Rismani-Yazdi et al. (2008), some aspects of cathodic limitations (ohmic and mass transport losses, substrate crossover, etc.), are discussed. In a review by Zhou et al. (2011), recent progress in anode and cathode and filling materials as three-dimensional electrodes for microbial fuel cells (MFCs) has been reviewed systematically, resulting in comprehensive insights into the characteristics, options, modifications, and evaluations of the electrode materials and their effects on various actual wastewater treatments. Some existing problems of electrode materials in current MFCs are summarized, and the outlook for future development is also suggested. 

Various metals have been explored to replace Pt, including Fe, Co, Mn, and Pb. Among these metals, cobalt and iron are often used with tetramethoxy-phenylporphyrin (TMPP) or phthalocyanine (Pc) to form metal macrocyclic complexes, which demonstrate performance comparable with Pt in neutral pH conditions. FePc supported on KJB carbon (FePc-KJB) produced a power density of 634 mW m , which is higher than 593 mW m of Pt cathode and other cathodes with metal macrocyclic complexes, including CoTMPP, FeCoTMPP, Co Pc, and FeCuPc [64]. The comparison of FePc and CoTMPP with platinum-based system demonstrated the potential of transition metal-based materials for substitution of the traditional cathode materials in microbial fuel cells [65]. Cheng et al. also demonstrated that the performance of... 

The unique combination of high mechanical stability, electrical conductivity, and surface area make carbon nanotubes (CNTs) a popular material for a wide range of biomedical applications, from microbial fuel cells to biochemical sensors [91-94]. Accordingly, CP composites have been investigated to synergize both mechanical and electrical properties of CNTs. 

The combination of favorable properties of PANI and TiO opens the possibility for various applications of PANI/TiO nanocomposite materials, such as piezoresistivity devices [41], electrochromic devices [99,118], photoelectrochemical devices [43,76], photovoltaic devices/solar cells [44,50,60,61,93,119], optoelectronic devices/UV detectors [115], catalysts [80], photocatalysts [52,63,74,75,78,84,87,97,104,107,121,122,125], photoelectrocatalysts [122,123], sensors [56,61,65,69,85,86,95,120,124], photoelectrochemical [110] and microbial fuel cells [71], supercapacitors [90,92,100,109,111], anode materials for lithium-ion batteries [101,102], materials for corrosion protection [82,113], microwave absorption materials [77,87,89], and electrorheological fluids [105,106]. In comparison with PANI, the covalently bonded PANI/TiO hybrids showed significant enhancement in optical contrast and coloration efficiency [99]. It was observed that the TiO nanodomains covalently bonded to PANI can act as electron acceptors, reducing the oxidation potential and band gap of PANI, thus improving the long-term electrochromic stability [99]. Colloidal... 

Due to the outstanding electrical and electrochemical properties of CNT/PANI, composite materials have also been applied as anode for a microbial fuel cell [335], high performance supercapacitors [333,336,337], and as modified electrode for the reduction of nitrite [331]. 

There are clear differences between chemical and microbial fuel cell anodes. The most obvious difference is that anodes of MFCs must be able to support the growth of biological organisms. MFC anodes must also be highly conductive in order to efficiently collect electrons produced by bacteria as small increases in material resistance can have a significant impact on maximum power outputs. Other considerations when selecting an anode material include the expense of the material and the ability for it to be manufactured on a large scale. 

Logan, B.E. (2005) Materials and configuration for scalable microbial fuel cells. Provisional patent application, PST 20918, PSU 2006-3173, Penn State University. 

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