PEM fuel cell electrodes using Single Wall Carbon Nanotubes
- PDF / 208,884 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 105 Downloads / 244 Views
0885-A02-09.1
PEM fuel cell electrodes using Single Wall Carbon Nanotubes Padraig Moloney1, Chad Huffman2, Micah Springer1, Olga Gorelik2, Pasha Nikolaev2, Edward Sosa2, Sivaram Arepalli2, Leonard Yowell1 1 NASA Johnson Space Center, Houston, Texas; 2 ERC Inc./NASA Johnson Space Center, Houston, Texas ABSTRACT Single wall carbon nanotubes (SWCNT) have previously been considered potential catalyst supports in proton exchange membrane fuel cells (PEMFC) [1]. Earlier research and development of SWCNT for PEMFC catalyst supports has been advanced by utilizing differing SWCNT purities and carbon blacks in differing ratios. This study validates the performance of SWCNT and introduces new concepts for SWCNT membrane fabrication. INTRODUCTION SWCNT continue to be investigated as an ideal catalyst support material for PEMFC. Theoretically, SWCNT are ideal for this role due to material advantages over the incumbent carbon black supports such as high surface areas, porosities, thermal and electrical conductivities [1,2]. This research is driven by the current space exploration effort at NASA which demands higher power densities and reliability from power and energy systems. The new space exploration effort soon to be embarked by NASA and its partners demands higher power densities and dependability. Previous research has suggested that the purity and thickness of SWCNT catalyst support or electrodes are dominant in catalyst support influences on PEMFC performance [3,4]. This study aims to confirm these findings through materials characterization and fuel cell testing. It also seeks to draw more thorough conclusions on optimal SWCNT morphologies by the variation of processing, fabrication and testing techniques. EXPERIMENTAL DETAILS Catalyst Support Layer Preparation & Characterization Cinke et al reported 1300 m2g-1 starting with raw SWCNT fabricated by the high pressure carbon monoxide (HiPco) technique [5]. This provided a starting point for a material processing to maximize useful surface area and porosity. Electrodes were formed after the first and second steps of this two step technique; the second step being a purification step. Catalyst support layers fabricated after the first step were also “purified in place” by soft baking the bucky papers. This was achieved by first heating the dried papers in humidified air, followed by bubbling in HCL. Reference cathodes and anodes were created using a standard painting process of inks with compositions of liquid Nafion, isopropyl alcohol, glycerol, tetrabutyl ammonium hydroxide, and Etek XC-72R 20% platinum loaded carbon black. This protocol was modified to create additional catalyst support layers using purified SWCNT. Platinum catalyst was impregnated into the catalyst supports using a procedure similar to that reported by Chen et al [6]. The platinum impregnated catalyst supports were characterized
0885-A02-09.2
by SEM & EDS (Hitachi S4800) in conjunction with TGA (Netzch STA 449C) and TEM & EDS (JEOL). Membrane Electrode Assembly Preparation & Characterization In advance
Data Loading...
