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Title: Membrane crystallinity and fuel crossover in direct ethanol fuel cells with Nafion composite membranes containing phosphotungstic acid

Interest has been growing in direct ethanol fuel cells (DEFCs) due to their non-toxicity, low cost and potential contribution to energy issues in third world countries. A reduction in fuel cross-over is of key importance to enhance the performance of DEFCs that operate at low temperatures (<100 °C). We report on the effect of the addition of phosphotungstic acid (PWA) in Nafion membrane on the ethanol-crossover for DEFC application. A set of PWANafion composite membranes (PWA 0, 5, 10, 15, 20 wt%) was prepared by solution casting and their microstructures, diffraction patterns and permeability were systematically characterized. The significant reduction in ethanol-crossover was observed with increasing PWA concentration in PWA-Nafion membranes, which was mainly attributed to an improvement in crystallinity of the membrane. PWA provides additional nucleation sites during solidification leading to higher crystallinity, which is supported by the membrane permeability tests. These PWA-Nafion composites were implemented in proto-type DEFC devices as a membrane and the maximum power density achieved was 22% higher than that of commercial Nafion-117 device.
Authors:
 [1] ;  [2] ;  [1] ;  [1] ;  [1] ;  [1] ;  [3] ;  [4] ;  [1]
  1. Korea Advanced Inst. Science and Technology (KAIST), Daejeon (Korea, Republic of). Dept. of Materials Science and Engineering
  2. Baylor Univ., Waco, TX (United States). Dept. of Mechanical Engineering
  3. Nelson Mandela African Inst. of Science and Technology, Arusha (Tanzania)
  4. Korea Advanced Inst. Science and Technology (KAIST), Daejeon (Korea, Republic of). Dept. of Materials Science and Engineering; Argonne National Lab. (ANL), Argonne, IL (United States). Materials Science Division
Publication Date:
Grant/Contract Number:
AC02-06CH11357
Type:
Accepted Manuscript
Journal Name:
Journal of Materials Science
Additional Journal Information:
Journal Volume: 52; Journal Issue: 5; Journal ID: ISSN 0022-2461
Publisher:
Springer
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22); National Research Foundation of Korea (NRF)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; Nafion; composite membrane; direct ethanol fuel cell (DEFC); ethanol-crossover; phosphotungstic acid
OSTI Identifier:
1340207