Polybenzimidazole composite membranes containing imidazole functionalized graphene oxide showing high proton conductivity and improved physicochemical properties

• Published in: International journal of hydrogen energy 2021-03, Vol.46 (22), p.12254-12262
• Main Authors: Kim, Junghwan, Kim, Kihyun, Ko, Taeyun, Han, Jusung, Lee, Jong-Chan
• Format: Article
• Language: English
• Subjects: Graphene oxide; HT-PEMFC; Polybenzimidazole; Polymer composite; Proton exchange membrane
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2020.02.193

Polymer composite membranes are fabricated using poly[2,2'-(m-phenylene)-5,5′-bibenzimidazole] (PBI) as a polymer matrix and imidazole functionalized graphene oxide (ImGO) as a filler material for high temperature proton exchange membrane fuel cell applications. ImGO is prepared by the reaction of o-phenylenediamine with graphene oxide (GO). The compatibility of ImGO with PBI matrix is found to be better than that of GO, and as a result PBI composite membrane having ImGO exhibits improved physicochemical properties and larger proton conductivity compared with pure PBI and PBI composite membrane having GO. For example, PBI composite membrane having 0.5 wt% of ImGO shows enhanced tensile strength (219.2 MPa) with minimal decrease of elongation at break value (28.8%) compared with PBI composite membrane having 0.5 wt% of GO (215.5 MPa, 15.4%) and pure PBI membrane without any filler (181.0 MPa, 34.8%). The proton conductivity of this membrane, at 150 °C under anhydrous condition, is 77.52 mS cm−1. •A novel filler material (ImGO) is synthesized by functionalizing graphene oxide.•The compatibility of ImGO with PBI matrix is superior to that of GO.•PBI/ImGO membrane exhibits improved physicochemical properties.•PBI/ImGO membrane shows 77.52 mS cm−1 at 150 °C under anhydrous condition.