Carbon nanotube, graphene oxide and montmorillonite as conductive fillers in polymer electrolyte membrane for fuel cell: an overview

Abstract

Summary 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 cm2/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.

An overview of substrate stiffness guided cellular response and its applications in tissue regeneration

“…Incorporation of inorganic bioactive fillers, including calcium phosphates [ 53 , 87 ], silicate [ 88 ], BG [ 89 ], CNT [ 90 ], and graphene [ 91 ], into polymeric substrates has been prepared with an emphasis on the fabrication of hybrid biocomposites with tunable stiffness, as well as the adjustment of biological performance. As one of the primary components of bone ECM, calcium phosphates, mainly in the form of HAp [ 53 , 92 ], have been widely used as osteoinductive fillers in bone substrates due to their high strength and outstanding osteoconductivity.…”

Progress and challenges: Review for direct liquid fuel cell

“…Sulfonated poly(ether ketone) (SPEEK) is one of the best candidates for replacement of the membrane Nafion in the near future, thanks to its cost‐competence, high chemical, and mechanical stability 78,79 . However, due to high water uptake and floating in those conditions, it shows high MCO at high ion exchange capacity 80,81 . The sulfonated GO‐paper membrane composite sandwiched among two layers of SPEEK (Figure 4A has greater proton conduction and lower permeability toward methanol than the Nafion 112 at 80°C 83,84 .…”

Progress of g‐C 3 N 4 and carbon‐based material composite in fuel cell application

“…Electrical conductivity can be achieved through polymer membranes, but they have significant drawbacks, including high manufacturing costs and high fuel crossover. Although a few polymer‐based membranes work well as separators in fuel cells, limitations such as mechanical properties as well as water transport may be raised due to the large fraction of water that may be absorbed in the membrane 236 . The ideal ion exchange membrane should have strong proton conductivity as well as outstanding mechanical and chemical characteristics.…”