title: Mechanical Behavior of Free-Standing Fuel Cell Electrodes on Water Surface.
abstract: Fundamental understanding of the mechanical behavior of polymer electrolyte fuel cell electrodes as free-standing materials is essential to develop mechanically robust fuel cells. However, this has been a significant challenge due to critical difficulties, such as separating the pristine electrode from the substrate without damage and precisely measuring the mechanical properties of the very fragile and thin electrodes. We report the mechanical behavior of free-standing fuel cell electrodes on the water surface through adopting an innovative ice-assisted separation method to separate the electrode from decal transfer film. It is found that doubling the ionomer content in electrodes increases not only the tensile stress at the break and the Young's modulus (E) of the electrodes by approximately 2.1-3.5 and 1.7-2.4 times, respectively, but also the elongation at the break by approximately 1.5-1.7 times, which indicates that stronger, stiffer, and tougher electrodes are attained with increasing ionomer content, which have been of significant interest in materials research fields. The scaling law relationship between Young's modulus and density (ρ) has been unveiled as E ∼ ρ(1.6), and it is compared with other materials. These findings can be used to develop mechanically robust electrodes for fuel cell applications.
authors.affiliation: Department of Mechanical Engineering, KAIST , Daejeon, 305-701, Republic of Korea.
authors.forename: Sanwi
authors.initials: S
authors.lastname: Kim
authors.affiliation: Department of Mechanical Engineering, KAIST , Daejeon, 305-701, Republic of Korea.
authors.forename: Jae-Han
authors.initials: JH
authors.lastname: Kim
authors.affiliation: Fuel Cell Vehicle Team 1, Eco-Technology Center, Research & Development Division, Hyundai Motor Company, Yongin-si, Gyeonggi-do 446-716, Republic of Korea.
authors.forename: Jong-Gil
authors.initials: JG
authors.lastname: Oh
authors.affiliation: Department of Mechanical Engineering, KAIST , Daejeon, 305-701, Republic of Korea.
authors.forename: Kyung-Lim
authors.initials: KL
authors.lastname: Jang
authors.affiliation: Fuel Cell Vehicle Team 1, Eco-Technology Center, Research & Development Division, Hyundai Motor Company, Yongin-si, Gyeonggi-do 446-716, Republic of Korea.
authors.forename: Byeong-Heon
authors.initials: BH
authors.lastname: Jeong
authors.affiliation: Fuel Cell Vehicle Team 1, Eco-Technology Center, Research & Development Division, Hyundai Motor Company, Yongin-si, Gyeonggi-do 446-716, Republic of Korea.
authors.forename: Bo Ki
authors.initials: BK
authors.lastname: Hong
authors.affiliation: Department of Mechanical Engineering, KAIST , Daejeon, 305-701, Republic of Korea.
authors.forename: Taek-Soo
authors.initials: TS
authors.lastname: Kim
keywords: Young’s modulus; electrode; fuel cell; ice-assisted separation; mechanical properties