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

Abstract

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 effi ciency 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 fi rst be commercialized for small portable power applications (e.g., the displacement of batteries in consumer electronic applications), where the shorter product lifetimes ( ∼ 1-2 yrs for a battery versus 8-15 yrs for a car) and the much higher price points ( ∼ $10/W for a laptop battery vs. ∼ $0.05/W for a vehicle engine) provide a more attractive entry point. While such applications are not likely to signifi cantly 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.

Reaction Mechanisms of the Electrochemical Conversion of Carbon Dioxide to Formic Acid on Tin Oxide Electrodes

“…Formic acid has a very high volumetric hydrogen density of 53 g H 2 per liter and can be spontaneously transformed into H 2 fuel under ambient conditions by a formic acid dehydrogenation catalyst . In addition, it can provide much higher volumetric energy density (2086 Wh L −1 ) than H 2 fuel …”

PdAg/CNT catalyzed alcohol oxidation reaction for high-performance anion exchange membrane direct alcohol fuel cell (alcohol = methanol, ethanol, ethylene glycol and glycerol)

“…[9,10] Although Pt's catalytic activity with respect to methanol oxidation reaction 6 (MOR) [11], ethanol oxidation reaction (EOR) [12], ethylene glycol oxidation (EGOR) [13] and glycerol oxidation reaction (GOR) [14] can be very high in DAFCs, its scarcity results in a high price (> $50 g -1 ). One method of reducing the cost of catalyst layer is to lower down the loading of Pt, while another method is to replace Pt with more abundant and less expensive Pd.…”

A review on durability issues and restoration techniques in long-term operations of direct methanol fuel cells

“…Though more efforts have to be made to reduce the cost and to improve the performance and durability, the DMFC systems are expected to be first commercialized in the consumer electronics and lighttransportation applications where constraints of output power and cost are relatively flexible. The advantages as well as technical challenges of DMFCs in comparison to the PEMFCs have been thoroughly discussed in a recent review paper [5].…”