Nanoporous separator and low fuel concentration to minimize crossover in direct methanol laminar flow fuel cells

作者：Hollinger A S; Maloney R J; Jayashree R S; Natarajan D; Markoski L J^*; Kenis P J A

来源：Journal of Power Sources, 2010, 195(11): 3523-3528.

DOI：10.1016/j.jpowsour.2009.12.063

• Laminar flow
• Fuel cell
• Multichannel
• Methanol crossover
• Separator

Laminar flow fuel cells (LFFCs) overcome some key issues - most notably fuel crossover and water management - that typically hamper conventional polymer electrolyte-based fuel cells. Here we report two methods to further minimize fuel crossover in LFFCs: (i) reducing the cross-sectional area between the fuel and electrolyte streams, and (ii) reducing the driving force of fuel crossover, i.e. the fuel concentration gradient. First, we integrated a nanoporous tracketch separator at the interface of the fuel and electrolyte streams in a single-channel LFFC to dramatically reduce the cross-sectional area across which methanol can diffuse. Maximum power densities of 48 and 70 MW cm(-2) were obtained without and with a separator, respectively, when using I M methanol. This simple design improvement reduces losses at the cathode leading to better performance and enables thinner cells, which is attractive in portable applications. Second, we demonstrated a multichannel cell that utilizes low methanol concentrations (<300 mM) to reduce the driving force for methanol diffusion to the cathode. Using 125 mM methanol as the fuel, a maximum power density of 90 mW cm(-2) was obtained. This multichannel cell further simplifies the LFFC design (one stream only) and its operation, thereby extending its potential for commercial application.

• 出版日期2010-6-1