Effect of variation of hydrophobicity of anode diffusion media along the through-plane direction in direct methanol fuel cells |
| |
Authors: | Kyungmun Kang Sunghyun Park Geonhui Gwak Arae Jo Misun Kim Young-Don Lim Whan-Gi Kim Taewhan Hong Dongmin Kim Hyunchul Ju |
| |
Affiliation: | 1. School of Mechanical Engineering, Inha University, 253 Yonghyun-Dong, Nam-Gu, Incheon 402-751, Republic of Korea;2. Department of Applied Chemistry, Konkuk University, 322 Danwol, Chungju, Chungbuk 380-701, Republic of Korea;3. Department of Materials Science and Engineering, Korea National University of Transportation, 50 Daehak-ro, Chungju, Chungbuk 380-702, Republic of Korea;4. Department of Material Engineering & Science, Hongik University, Jochiwon-eup, Yeongi-gun, Chungnam 339-701, Republic of Korea |
| |
Abstract: | Reducing methanol crossover from the anode to cathode in direct methanol fuel cells (DMFCs) is critical for attaining high cell performance and fuel utilization, particularly when highly concentrated methanol fuel is fed into DMFCs. In this study, we present a novel design of anode diffusion media (DM) wherein spatial variation of hydrophobicity along the through-plane direction is realized by special polytetrafluoroethylene (PTFE) coating procedure. According to the capillary transport theory for porous media, the anode DM design can significantly affect both methanol and water transport processes in DMFCs. To examine its influence, three different membrane-electrode assemblies are fabricated and tested for various methanol feed concentrations. Polarization curves show that cell performance at high methanol feed concentration conditions is greatly improved with the anode DM design with increasing hydrophobicity toward the anode catalyst layer. In addition, we investigate the influence of the wettability of the anode microporous layer (MPL) on cell performance and show that for DMFC operation at high methanol feed concentration, the hydrophilic anode MPL fabricated with an ionomer binder is more beneficial than conventional hydrophobic MPLs fabricated with PTFE. This paper highlights that controlling wetting characteristics of the anode DM and MPL is of paramount importance for mitigating methanol crossover in DMFCs. |
| |
Keywords: | Direct methanol fuel cell Diffusion media Methanol crossover High concentration methanol fuel |
本文献已被 ScienceDirect 等数据库收录! |
|