In:
ECS Meeting Abstracts, The Electrochemical Society, Vol. MA2015-02, No. 37 ( 2015-07-07), p. 1464-1464
Abstract:
Medium Temperature – Polymer Electrolyte Membrane Fuel Cells (MT-PEMFCs) operate at temperatures between 80 °C and 120 °C. They show various advantages compared to traditional low temperature PEMFCs operating up to 80 °C: The management of liquid water is simplified, the electrode kinetics are enhanced and the tolerance to impurities contained in the reactant stream is increased [1–6] . However, huge deficits in terms of cell performance and durability to date hinder the application of MT-PEMFCs in the field of hydrogen mobility [7] . We present a novel manufacturing method called ‘direct membrane deposition’ [8] in combination with TiO 2 reinforcement which enables well performing MT-PEMFCs. The direct deposition of the reinforced membrane is realized by drop casting a dispersion of Nafion® and TiO 2 nanoparticles onto anode and cathode gas diffusion electrodes. The fuel cell is assembled with the two membrane layers facing each other, completely substituting the commonly used membrane foil. A scheme of the membrane electrode assembly (MEA) fabricated for this work is depicted in Figure 1 a). MT-PEMFCs constructed this way allow stable fuel cell operation at 120 °C with a maximum power density of 2.0 W/cm 2 (H 2 /O 2 ; 0.5/0.5 L/min; 300/300 kPa abs. , 90% RH). With increasing temperature from 80 °C to 120 °C, the membrane resistance of the TiO 2 reinforced directly deposited membrane increases by only 10 % whereas the membrane resistance of a non-reinforced directly deposited membrane increases by 54 %. At 100 °C (120°C) the maximum power density of the fuel cell with directly deposited TiO 2 reinforced membrane is 27 % (9 %) higher than the maximum power density of our reference system. The corresponding polarization curves are depicted in Figure 1 b). The reference fuel cell was manufactured with a Nafion® HP (DuPont) membrane, which, to our knowledge, is the thinnest commercially available reinforced membrane. As the main reason for the higher power densities compared to a state-of-the-art Nafion® HP membrane a lower membrane- and charge transfer resistance is found. In this work we show that TiO 2 reinforcement has proven to effectively stabilize the membrane resistance of directly deposited Nafion® membranes at elevated fuel cell operation temperatures. Surprisingly, MT-PEMFCs constructed this way are able to outperform even state-of-the-art Nafion® HP membranes. Figure 1 : a) Illustration of the membrane electrode assembly (MEA) fabricated in this work. A thin TiO 2 reinforced Nafion® layer is deposited directly on both anode and cathode gas diffusion electrodes. A thin subgasket prevents hydrogen and current crossover through the end faces of the active area. b) Shows a comparison of the polarization curves for a directly deposited membrane (DDM) to a commercial Nafion® HP (DuPont) membrane. For each membrane the current density characteristics power density is evaluated at 100°C (blue dashed curves) and 120°C (red curves). The operation conditions were: H 2 /O 2 ; 0.5/0.5 L/min; 300/300 kPa, 90% RH. Acknowledgements This work was funded by the German Federal Ministry of Education BMBF within the project “Gecko” (03SF0454C). References [1] V. P. McConnell, Fuel Cells Bulletin 2009, 12. [2] Q. Li, R. He, J. O. Jensen, N. J. Bjerrum, Chem. Mater. 2003, 15, 4896. [3] J. Zhang, Z. Xie, J. Zhang, Y. Tang, C. Song, T. Navessin, Z. Shi, D. Song, H. Wang, D. P. Wilkinson, Z.-S. Liu, S. Holdcroft, J. Power Sources 2006, 160, 872. [4] J.-R. Kim, J. S. Yi, T.-W. Song, J. Power Sources 2012, 220, 54. [5] A. Chandan, M. Hattenberger, A. El-kharouf, S. Du, A. Dhir, V. Self, B. G. Pollet, A. Ingram, W. Bujalski, J. Power Sources 2013, 231, 264. [6] S. Bose, T. Kuila, Nguyen, Thi Xuan Hien, N. H. Kim, K.-t. Lau, J. H. Lee, Progress in Polymer Science 2011, 36, 813. [7] A. Stassi, I. Gatto, E. Passalacqua, V. Antonucci, A. S. Arico, L. Merlo, C. Oldani, E. Pagano, J. Power Sources 2011, 196, 8925. [8] M. Klingele, M. Breitwieser, R. Zengerle, S. Thiele, J. Mater. Chem. A 2015. Figure 1
Type of Medium:
Online Resource
ISSN:
2151-2043
DOI:
10.1149/MA2015-02/37/1464
Language:
Unknown
Publisher:
The Electrochemical Society
Publication Date:
2015
detail.hit.zdb_id:
2438749-6
