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Cross‐linked polymer electrolyte membrane based on a highly branched sulfonated polyimide with improved electrochemical properties for fuel cell applications
Author(s) -
Hu Meishao,
Zhang Boping,
Chen Jiale,
Xu Muzi,
Liu Danqing,
Wang Lei
Publication year - 2019
Publication title -
international journal of energy research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.808
H-Index - 95
eISSN - 1099-114X
pISSN - 0363-907X
DOI - 10.1002/er.4879
Subject(s) - membrane , proton exchange membrane fuel cell , electrolyte , polyimide , polymer , chemical engineering , conductivity , electrochemistry , polymer chemistry , materials science , chemistry , branching (polymer chemistry) , hydrolysis , organic chemistry , electrode , biochemistry , layer (electronics) , engineering
Summary Sulfonated polyimides (SPIs) are extremely suitable as polymer electrolyte membranes (PEMs) for fuel cell applications, except for their poor water stability. Cross‐linking is a method that is commonly used to improve the weak hydrolytic stability of SPI membranes. However, this strategy significantly decreases the proton conductivity of the membrane, which leads to a lower fuel cell power density. In this work, a cross‐linked SPI membrane containing a highly branched polymer main chain was fabricated as a PEM. With a similar ion‐exchange capacity value, the cross‐linked membrane containing branched main chains showed an improved proton conductivity. Also, this membrane remained 92.3% of pristine weight after a hydrolytic stability test about 120 hours. In a single direct methanol fuel cell, the cross‐linked membrane containing a branched structure showed a higher power density (53.4 mW cm −2 ) than the common cross‐linked membrane (43.0 mW cm −2 ), indicating that branching is effective for improving the electrochemical properties of PEM‐based cross‐linked SPIs.