Modifying a proton conductive membrane by embedding a "barrier".
For development of proton conductive membranes, it is a difficult dilemma to balance proton conductivity and methanol permeability; however, this research proposes a simple strategy to solve this problem, i.e., embedding a proton conductive "barrier" into the perflorosulfonated matrix. The strategy is exemplified by embedding the amphoteric sulfonated poly(phthalazinone ether sulfone kentone) (SPPESK) into a semicrystalline perflorosulfonic acid polymer matrix (FSP). After being annealed, the domain of SPPESK is converted to the barrier. Two acid-base interactions constitute the barrier for both the transfer of protons and the blockage of methanol, respectively. On one hand, poorly hydrophilic ionic acid-base interactions (-SO(3)(-)...NH(+)-) are formed between sulfonic acid group and phthalazinone group through annealing and are useful for methanol blocking. On the other hand, more hydrophilic hydrogen-bonded acid-base interaction (-SO(3)H...(H(2)O)(n)...N-, n ≤ 3) can also be formed under hydrated condition and facilitate proton transport according to the Grotthuss-type mechanism. As a result, the final membrane exhibits an extremely low methanol permeability (30% of that of Nafion-112) and an excellent fuel cell performance (as compared with Nafion-112 at 80 °C).
Wu
Liang
L
CAS Key Laboratory of Soft Matter Chemistry, Laboratory of Functional Membranes, School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, Anhui 230026, People's Republic of China.
Huang
Chuanhui
C
Woo
Jung-Je
JJ
Wu
Dan
D
Yun
Sung-Hyun
SH
Seo
Seok-Jun
SJ
Xu
Tongwen
T
Moon
Seung-Hyeon
SH