Physico-chemical nanomaterials science

Study of the effects of the microstructure, contact stress and temperature on the area specific resistance of fuel cell materials
Podhurska V.Ya.1, Vasyliv B.D.1, Milewski Ja.2, Skibiński Ja.3, Dybiński O.2, Martsinchyk A.2, Rebis Ja.3
1 Department of Hydrogen Technologies and Alternative Energy Materials, Karpenko Physico-Mechanical Institute of the NAS of Ukraine, 5 Naukova str., Lviv 79060, Ukraine.
E-mail: podhurskavika@gmail.com
2 Institute of Heat Engineering, Warsaw University of Technology, 21/25 Nowowiejska str., Warsaw, 00-665, Poland
3 Faculty of Materials Science and Engineering, Warsaw University of Technology, 141 Wołoska str., Warsaw, 02-507, Poland

A fuel cell is a promising source of energy based on direct transformation of chemical energy into electricity. Traditionally, this device comprises a set of single fuel cells united in a stack. A single fuel cell consists of a dense electrolyte and porous electrodes applied to its opposite sides. Along with single fuel cells, an important component of the stack is the current collector, as it serves to supply gas mixtures and conduct electricity. The contact resistance between the current collector and the electrodes serves as a crucial characteristic of the fuel cell system determining its efficiency. Contact electrical resistance depends on the materials of the components and the clamping force. This work is aimed at studying the effect of microstructural parameters of the current collector and electrode materials and the applied load on the contact electrical resistance between them.
The change in the contact electrical resistance between the current collector and anode materials during heating and cooling under different contact stresses (0.09 MPa and 0.45 MPa) was studied.
As a result of experimental measurements, the kinetic dependences of the area specific resistance (ASR) of the nickel anode on the temperature in the operating temperature range of a fuel cell of 20–600 °C were obtained for heating and cooling cycles in air under loads of 49.05 N and 245.25 N, which correspond to the levels of contact stresses in bulk material 0.09 MPa and 0.45 MPa. It was found that at a temperature of 600 °С, the ASR of the nickel anode under contact stress of 0.45 MPa is 2.3–3 times lower than that under contact stress of 0.09 MPa.