Composite short-side-chain PFSA electrolyte membranes containing selectively modified halloysite nanotubes (HNTs)

Abstract

Aquivion membrane displays improved properties as compared to Nafion membrane, partly due to shorter side chains. However, some improvements are still necessary for proton exchange membrane fuel cell to operate at low relative humidity. To overcome this drawback, the addition of clay nanoparticle into the Aquivion matrix can be considered. In this study, different composite mem-branes have been prepared mixing short-side-chain PFSA (perfluorosulfonic acid) Aquivion and selectively modified halloysite nanotubes for PEMFC low relative humidity operation. Halloysites were grafted with fluorinated groups, sulfonated groups, or perfluoro-sulfonated groups on inner or outer surface of the tubes. The obtained composite membranes showed improved properties, especially higher water uptake associated with reduced swelling and better mechanical strength compared to pristine Aquivion membrane and commer-cially available Nafion HP used as reference. The best performance in this study was obtained with Aquivion loaded with 5 wt% of pretreated perfluoro-sul-fonated halloysite. The composite membrane, referred to as Aq/pHNT-SF5, displayed the largest water uptake and proton conductivity among the panel of membranes tested. The chemical stability was not affected by the presence of halloysite in the Aquivion matrix.

Sulfonated poly(ether ether ketone) membranes for vanadium redox flow battery enabled by the incorporation of ionic liquid‐covalent organic framework complex

“…However, the high cost and grave vanadium ion permeation of the PFSA membranes have severely hindered their industrialization. 6 To improve the ion selectivity of PFSA membranes, researchers modified the membranes with inorganic particles, 7 other polymers, 8 and mechanical treatment. 9,10 Although the performance has been improved, the high cost of PFSA membranes still prevented their further application in VRFB.…”

Ultra-robust, highly proton-conductive polymer carbon dot membranes through bioinspired complexation

“…6,7 Over the past decades, the organic-inorganic hybridization method has been widely utilized to regulate the physicochemical microenvironment and multiple interactions in membranes to synergistically improve proton conductivity and mechanical stability. [8][9][10] The sizes of commonly used inorganic llers (such as SiO 2 , 11 carbon nanotubes (CNTs 12 ), halloysite nanotubes (HNTs 13 ), graphene oxide (GO 14 ), MXenes, 15 and g-C 3 N 4 16 are usually tens to hundreds of nanometers, and the high density of inorganic llers and poor interface compatibility oen result in serious agglomeration even at lower ller content (<10 wt%), limiting the improvement of proton conductivity and mechanical stability of composite membranes. In recent years, zerodimensional polymer carbon dots (PCDs) have attracted intensive research interest attributed to their small size (usually 2-8 nm), lightweight, facile synthetic routes, and excellent interface compatibility with polyelectrolytes.…”