Hydrophobic Quaternized Poly(fluorene) Ionomers for Emerging Fuel Cells
Santosh Adhikari, Daniel P. Leonard, Katie Heeyum Lim, Eun Joo Park, Cy Fujimoto, Oscar Morales‐Collazo, Joan F. Brennecke, Zhendong Hu, Hongfei Jia, Yu Seung Kim
Abstract
Quaternized polymers as electrode ionomeric binders enable fuel cell operation under high-pH or anhydrous conditions. Herein we report quaternized poly(fluorene) ionomers with controlled hydrophobicity (contact angle of electrodes with the ionomers 109–164°) by changing the length of tethered fluoroalkyl chains. The anion-exchange membrane fuel cell employing the hydrophobic ionomer exhibits improved durability (voltage loss 0.41 mV h–1) through better water management. The high-temperature proton-exchange-membrane fuel cell using the ionomer shows superior H2/air performance (1.7 A cm–2 at 0.4 V). The finding in this study highlights the benefits of hydrophobic ionomers for emerging fuel cell applications.