Microbial Fuel Cells in Power Generation and Extended Applications - Biotechnology in China: Biofuels and Bioenergy - page 167

Fig. 1 Number of published articles on MFCs in China and the whole world (data are based on
the Scopus search using the keyword ''microbial fuel cell'')
The reported power output of MFCs at the laboratory scale has improved
drastically while the material cost has declined considerably in the past few years.
Meanwhile, the potential application scope of MFC has expanded from pure elec-
tricity generation to bioremediation, bioproduction and biosensors. Nonetheless,
MFC technology is still at a very early stage of development, and several challenges
are yet to be addressed if MFC is to become a practical viable technology.
The biggest barrier is still the low power output, which now seems to have reached a
plateau despite of the recent intensive efforts in configuration, material and micro-
organism optimization. This low power density is mainly due to the various energy
losses in the electrode reaction and electron-proton transfer. Another limiting factor
has been the high cost of materials, for example the common use of expensive proton
exchange membrane and platinum-loaded cathode. In addition, the significant
increase of overpotential with reactor size during scaling up and the gradual bio-
fouling of the separator all present barriers to its practical application. In all, major
improvements are required if practical applications of MFC technology are to
become feasible. Here, the recent efforts of Chinese researchers are highlighted, and
the major obstacles and future opportunities of MFC technology are discussed.
2 Recent Progress for Improved Power Generation
2.1 MFC configuration
2.1.1 Tubular MFCs
Innovation in MFC design has been driven by the desire to increase the power
output and scalability. Recently, tubular-type MFCs have become one area of
intensive study [ 3 , 8 ]. A tubular MFC differs from the conventional cube or