Enhanced durability of polymer electrolyte membrane fuel cells by functionalized 2D boron nitride nanoflakes.
We report boron nitride nanoflakes (BNNFs), for the first time, as a nanofiller for polymer electrolyte membranes in fuel cells. Utilizing the intrinsic mechanical strength of two-dimensional (2D) BN, addition of BNNFs even at a marginal content (0.3 wt %) significantly improves mechanical stability of the most representative hydrocarbon-type (HC-type) polymer electrolyte membrane, namely sulfonated poly(ether ether ketone) (sPEEK), during substantial water uptake through repeated wet/dry cycles. For facile processing with BNNFs that frequently suffer from poor dispersion in most organic solvents, we non-covalently functionalized BNNFs with 1-pyrenesulfonic acid (PSA). Besides good dispersion, PSA supports efficient proton transport through its sulfonic functional groups. Compared to bare sPEEK, the composite membrane containing BNNF nanofiller exhibited far improved long-term durability originating from enhanced dimensional stability and diminished chronic edge failure. This study suggests that introduction of properly functionalized 2D BNNFs is an effective strategy in making various HC-type membranes sustainable without sacrificing their original adventurous properties in polymer electrolyte membrane fuel cells.
Graduate School of EEWS (Energy, Environment, Water, and Sustainability), §Department of Material Science and Engineering, Graphene Research Center (GRS), and KAIST Institute NanoCentury, ⊥Department of Chemical and Biomolecular Engineering, and #Center for Nature-inspired Technology (CNiT), KAIST Institute NanoCentury, Korea Advanced Institute of Science and Technology , Daejeon 305-701, Korea.
Keun-Hwan
KH
Oh
Dongju
D
Lee
Min-Ju
MJ
Choo
Kwang Hyun
KH
Park
Seokwoo
S
Jeon
Soon Hyung
SH
Hong
Jung-Ki
JK
Park
Jang Wook
JW
Choi