title: Sulfonated polyimide/acid-functionalized graphene oxide composite polymer electrolyte membranes with improved proton conductivity and water-retention properties.
abstract: Sulfonated polyimide (SPI)/sulfonated propylsilane graphene oxide (SPSGO) was assessed to be a promising candidate for polymer electrolyte membranes (PEMs). Incorporation of multifunctionalized (-SO3H and -COOH) SPSGO in SPI matrix improved proton conductivity and thermal, mechanical, and chemical stabilities along with bound water content responsible for slow dehydration of the membrane matrix. The reported SPSGO/SPI composite PEM was designed to promote internal self-humidification, responsible for water-retention properties, and to promote proton conduction, due to the presence of different acidic functional groups. Strong hydrogen bonding between multifunctional groups thus led to the presence of interconnected hydrophobic graphene sheets and organic polymer chains, which provides hydrophobic-hydrophilic phase separation and suitable architecture of proton-conducting channels. In single-cell direct methanol fuel cell tests, SPI/SPSGO-8 exhibited 75.06 mW·cm(-2) maximum power density (in comparison with commercial Nafion 117 membrane, 62.40 mW·cm(-2)) under 2 M methanol fuel at 70 °C.
authors.affiliation: Electro-Membrane Processes Division and ‡Academy of Scientific and Innovative Research, Central Salt and Marine Chemicals Research Institute, Council of Scientific & Industrial Research , Gijubhai Badheka Marg, Bhavnagar 364 002, Gujarat, India.
authors.forename: Ravi P
authors.initials: RP
authors.lastname: Pandey
authors.forename: Amit K
authors.initials: AK
authors.lastname: Thakur
authors.forename: Vinod K
authors.initials: VK
authors.lastname: Shahi
keywords: direct methanol fuel cell; improved water-retention properties; polymer electrolyte membranes; sulfonated graphene oxide; sulfonated polyimide