TY  - JOUR
UR  - https://pubs.aip.org/aip/adv/article/9/6/065206/22190/Heterogeneous-cell-performance-of-polymer
SN  - 2158-3226
VL  - 9
TI  - Heterogeneous Cell Performance of Polymer Electrolyte Fuel Cell at High Current Operation: Respiration Mode as Non-Equilibrium Phenomenon
SP  - 1
ID  - repounp38681
PB  - AIP Publishing
IS  - 6
Y1  - 2019/06/12/
N2  - The heterogeneous performance of polymer electrolyte fuel cell in space and time was discussed for operation at high current density. The cell voltage, detected by a segmented electrode, varies along a gas flow channel from upper to bottom stream and oscillates in time, which is referred as a respiration mode. At the higher current, the cell voltage at different positions started to be synchronized, as the current density increases. In order to investigate a role of water on the respiration, we employed a new method of contrast variation for small-angle neutron scattering (SANS) using deuterium (D2) gas as a fuel. By using D2, we introduce special scattering contrast in a polymer electrolyte film (Nafion®), when the film is originally swollen by H2O. After switching from H2 to D2 gas (humidified with H2O), we found that SANS intensity significantly decreases about 40% at the q-position of scattering maximum (qm) originating from the water-microdomains in the polymer electrolyte. After quantitative analyses of the scattering intensity, it was elucidated that 20 wt% of the total water is occupied by D2O as a steady state. At around the average intensity, SANS intensity oscillates with a time interval ?100sec, which corresponds to the respiration mode found for voltage. The respiration behavior is considered as a non-linear & non-equilibrium phenomenon in an open system, where water flooding plays a role of feedback to decelerate fuel transportation and chemical reaction of water generation.
KW  - Polymer electrolyte fuel cell
KW  -  heterogeneous performance
KW  -  respiration mode
KW  -  non-equilibrium phenomenon
KW  -  small-angle neutron scattering
KW  -  water flooding
KW  -  Nafion membrane
EP  - 9
JF  - AIP Advances
A1  - Koizumi, Satoshi
A1  - Ueda, Satoru
A1  - Ananda, Putra
A1  - Tsutsumi, Yasuyuki
AV  - public
ER  -