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Sulfonated poly (vinylidene fluoride‐co‐hexafluoropropylene) nanocomposite membranes with high selectivity, stability, and vanadium‐ion barrier for vanadium redox flow batteries
Author(s) -
Divya Kumar,
Rana Dipak,
Saraswathi Meenakshi Sundaram Sri Abirami,
Gokila Pandian,
Nagendran Alagumalai
Publication year - 2020
Publication title -
polymers for advanced technologies
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.61
H-Index - 90
eISSN - 1099-1581
pISSN - 1042-7147
DOI - 10.1002/pat.5057
Subject(s) - materials science , vanadium , membrane , nanocomposite , chemical engineering , hexafluoropropylene , flow battery , nafion , graphene , polymer chemistry , composite material , electrochemistry , electrolyte , nanotechnology , electrode , copolymer , polymer , chemistry , metallurgy , biochemistry , tetrafluoroethylene , engineering
Polyethyleneimine‐functionalized reduced graphene oxide (PEI‐RGO)‐embedded sulfonated poly (vinylidene fluoride‐co‐hexafluoropropylene) (SPVDF‐co‐HFP) acid‐base composite membranes are fabricated by solution casting method for vanadium redox flow battery (VRFB) applications. The denser and crumbled morphology revealed by FESEM images and EDX results indicates the successful synthesis of PEI‐RGO nanosheets. The interfacial acid‐base pairs formed between PEI‐RGO and SPVDF‐co‐HFP matrix of composite membranes result in improvement of ion exchange capacity, water uptake, proton conductivity, as well as effective control in swelling ratio and vanadium‐ion permeability. In addition, the dispersing ability of PEI‐RGO in the SPVDF‐co‐HFP matrix improved the thermal and mechanical stability of the composite membranes. Homogeneous dispersion of PEI‐RGO nanosheets at the SPVDF‐co‐HFP surface is revealed by the FESEM images of the composite membranes, and their presence is confirmed by EDX results. The SPVDF‐co‐HFP membrane with 0.75 wt% PEI‐RGO exhibited the highest proton conductivity of 5.69 × 10 −3 Scm −1 at 25°C, membrane selectivity of 25.52 × 10 −4 Scm −3 min, and lowest vanadium‐ion permeability of 2.23 × 10 −8 cm 2 min −1 . Overall results suggested that the SPVDF‐co‐HFP‐0.75 nanocomposite membranes are found to be a suitable alternative for commercially costly Nafion in VRFB applications.