A review on direct methanol fuel cells - In the perspective of energy and sustainability

The direct methanol fuel cell (DMFC) enables the direct conversion of the chemical energy stored in liquid methanol fuel to electrical energy, with water and carbon dioxide as by-products. Compared to the more well-known hydrogen fueled polymer electrolyte membrane fuel cells (H-2-PEMFCs), DMFCs present several intriguing advantages as well as a number of challenges. This review examines the technological, environmental, and policy aspects of direct methanol fuel cells (DMFCs). The DMFC enables the direct conversion of the chemical energy stored in liquid methanol fuel to electrical energy, with water and carbon dioxide as byproducts. Compared to the more well-known hydrogen fueled PEMFCs, DMFCs present several intriguing advantages as well as a number of challenges. Factors impeding DMFC commercialization include the typically lower efficiency and power density, as well as the higher cost of DMFCs compared to H-2-based fuel cells. Because of these issues, it is likely that DMFC technology will first be commercialized for small portable power applications (e.g., the displacement of batteries in consumer electronic applications), where the shorter product lifetimes (similar to 1-2 yrs for a battery versus 8-15 yrs for a car) and the much higher price points (similar to$10/W for a laptop battery vs. similar to$0.05/W for a vehicle engine) provide a more attractive entry point. While such applications are not likely to significantly impact the global energy sustainability picture, they provide an important initial market for fuel cell technology. As such, in this review, we provide an overview of recent research and the challenges to the development of DMFCs for both the portable (shorter-term) and transport (longer-term) sectors.