Direct methanol fuel cells DMFC tests

Li X, Faghri A (2013) Review and advances of direct methanol fuel cells (DMFCs) part L Design, fabrication, and testing with high concentration methanol solutions. J Power Sources 226 223-240. doi 10.1016/j.jpowsour.2012.10.061... 

Liu JG, Zhou ZH, Zhao XX, Xin Q, Sun GQ, Yi BL. Studies on performance degradation of a direct methanol fuel cell (DMFC) in life test. Phys Chem Chem Ph5rs 2004 6 134. 

Of any fuel cell application to date, this is the area with the largest number of fuel cell types being developed. In other words, molten carbonate fuel cell (MCFC), PAFC, proton-exchange membrane (PEM) and solid oxide fuel cell (SOFC) units are all being developed and tested for adoption in scales of > 10 kW. The only mainstream fuel cell that is not being developed for these applications is direct methanol fuel cell (DMFC). 

Table 2 Micro-FC prototypes, incorporating mesoporous silicon in the core system, reported in the hterature for DHFC (direct hydrogen fuel cell), DMFC (direct methanol fuel cell), and RHFC (reformed hydrogen fuel cell). Aacttve is the active surface, OCV the open circuit voltage of the cell, PP the power peak during the test, fuel A and K are the fuels provided at anode (A) and cathode (K), T° is the temperature during the test, RT is the room temperature, MeOH is methanol and EtOFI is ethanol...

Silva et al. [63] developed a mixture of sulfonated-poly(etheretherketone) (s-PEEK) with a 42 or 68% degree of sulfonation, m-PBI, and zirconium phosphate (ZrP) for use in a direct methanol fuel cell. This blend was originally designed to increase the chemical and thermal stability of the s-PEEK. The proton conductivity and DMFC performance were also tested. Although the membrane swelling and methanol permeability decreased, the membrane conductivity also decreased. In general terms, however, the addition of the m-PBI and ZrP imparted chemical stability and increased DMFC efficiency at temperatures up to 130 °C. 

The preparation complexity of perfluorosulfonated membrane and the high cost have restricted PEMFC from commercialization. Many researchers are dedicated to the development of nonflnorinated PEM. The American company Dais has developed styrene/ethylene-bntylene/styrene triblock polymer [51]. This membrane is especially snitable for small power PEMFC working at room temperature. The lifetime of the membrane is up to 4000 h. Baglio did some experiments to test the performance comparison of portable direct methanol fuel cell mini-stacks between a low-cost nonfluorinated polymer electrolyte and Nafion membrane. He found that at room temperature, a single-cell nonfluorinated membrane can achieve maximum power density of about 18 mW/cm. As a comparison, the value was 31 mW/cm for Nafion 117 membrane. Despite the lower performance, the nonfluorinated membrane showed good characteristics for application in portable DMFCs especially regarded to the perspectives of significant cost reduction [52]. 

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