International Journal of Energy Research, Vol.45, No.2, 1309-1346, 2021
Carbon nanotube, graphene oxide and montmorillonite as conductive fillers in polymer electrolyte membrane for fuel cell: an overview
This study discusses three conductive materials-carbon nanotube, graphene oxide, and montmorillonite which recently being used as fillers in membranes of fuel cell application and commonly hybridized with polymers as the matrix. The polymer electrolyte membrane fuel cell (PEMFC) is using a polymer-based membrane as the electrolyte, which might require filler or functionalization to enhance their cell performance. This review provides brief information for the researcher who insists on improving the current PEM using these potential fillers, specified with required values of membrane properties measurement. It also entails the special features of the nanofillers concerning their chemical structure and electrochemical properties based on recent studies. As electricity is generated from an external fuel source, the membranes that are used should be more than 0.1 S/cm of proton conductivity, low fuel permeability (< 1.37 x 10(-6)cm(2)/s), cheap, and high stability in dry and wet condition. PEM is widely being utilized together with filler(s) incorporated as a purpose to overcome recent drawbacks encountered by the commercial Nafion membrane solely. Hence, the fillers embedded in the membrane are necessarily to have the promising characteristics, acknowledging the potential performances of three conductive nanofillers of (a) carbon nanotubes which is well-known of its electrical conducting potential with three cylindrical design, (b) graphene oxide which is a reactive carbonaceous material with its multifunctional groups and (c) montmorillonite which is one of the clay types that has tetrahedral and octahedral layers of alumina-silicates for producing better hybrid polymer electrolyte membrane. Highlights Carbon nanotube, graphene oxide, and montmorillonite are highly promising conductive fillers with outstanding cell performances based on previous studies. Carbon nanotube, graphene oxide, and montmorillonite are chosen as incorporated fillers recently due to their rolling up direction (chirality vector of graphene sheet), reactive functional groups attached on the carbon atoms and ionic multilayers of the tetrahedral and octahedral sheet, respectively. High proton conductivity, low electronic conductivity, low fuel permeability, low water transport, low production cost, and high mechanical stability in both dry and wet condition are properties that should be portrayed by a good hybrid membrane.