Reinforced Hydroxylated Boron Nitride on Porous Sulfonated Poly(ether sulfone) with Excellent Electrolyte Properties for H₂/O₂ Fuel Cells

Abstract

Designing a high-performing amorphous porous framework of the proton-conducting membrane with inherent SO3H moieties in the aromatic chain and impregnating the proton source is beneficial for developing an excellent electrolyte for the proton exchange membrane fuel cell. In this work, we synthesize the porous sulfonated poly­(ether sulfone) (PSPES) nanocomposite membranes with excellent proton conductivity and stability via modified non-solvent-induced phase inversion. The hydroxylated boron nitride (HBN) was prepared from the bulk BN through simple liquid exfoliation and hydroxylation, which yielded the few-layered sheets. The direct inclusion of HBN into the PSPES will be anchoring or filling on the microporous channels of the membrane, yielding outstanding stability with HBN retention ability and high conductivity. Thereby, an excellent synergistic effect between the PSPES and HBN through the functional groups (SO3H–OH) is shown, producing the proton transport bridge and continuous proton transfer channels within the porous structure. Besides, the current and power density of the 3.5 wt % HBN reinforced PSPES (PSPES-HBN2) membranes were improved to 795 mA cm–2 and 220 mW cm–2. The interconnected microporous PSPES-HBN2 membrane shows an excellent proton conductivity of 77.4 ± 3.87 mS cm–1 at 80 °C with 100% humidity and notably reduced membrane degradation after a 120 h durability test.

Energy Harvesting Using High-Strength and Flexible 3D-Printed Cellulose/Hexagonal Boron Nitride Nanosheet Composites

“…The peaks at 1588 and 1407 cm –1 can be attributed to the symmetric −CH stretching vibrations of −CH 2 and −CH 3 alkyl groups in CMC and symmetric −CO stretching vibrations. The peak at 1003 cm –1 is due to −C–O stretching vibrations. − FTIR spectra of exfoliated hBN and bulk hBN (Figure S2) display two significant peaks at 808 and 1386 cm –1 , which can be attributed to the out-of-plane B–N–B and in-plane B–N stretching in hBN, respectively. − In the FTIR spectra of 3D-printed hBN/CMC, the peak for asymmetric −CO stretching was shifted to 1711 cm –1 . Also, the peaks for symmetric −CH stretching vibrations and symmetric −CO stretching vibrations were shifted to 1572 and 1412 cm –1 .…”

Advances in boron nitride‐based materials for electrochemical energy storage and conversion

“…195 Moreover, the porosity of polymer membranes was effectively tuned by adding BNNSs, which not only improved the proton conductivity but also endowed them high stability at high temperature. 189,196 Devrim and coworkers discovered that polybenzimidazole/h-BN (PBI/h-BN) composite membranes showed a high conductivity of 260 mS cm −1 even at 180°C, indicating that BN-based membranes showed good perspective in the high-temperature PEMFC application. 197 Manimuthu and coworkers added 3.5 wt% hydroxylated h-BN into sulfonated poly (ether sulfone) membranes (PSPES-HBN2).…”

“…SEM images of the PSPES-HBN2 (Figure 9F) revealed the dense outer surface with an hierarchical micropores structure, which showed excellent proton conductivity of 77.4 mS cm −1 at 80°C with 100% humidity and notably reduced membrane degradation after a 120h durability test. 189…”

“…(E) Schematic representation of proton conduction mechanism along. (F) Photography and SEM images of the prepared membranes 189 . Copyright 2022, American Chemical Society.…”

“…For example, the proton conductivity of Nafion improved from 135 to 214 mS cm −1 after adding 0.75 wt% h‐BN 195 . Moreover, the porosity of polymer membranes was effectively tuned by adding BNNSs, which not only improved the proton conductivity but also endowed them high stability at high temperature 189,196 . Devrim and coworkers discovered that polybenzimidazole/h‐BN (PBI/h‐BN) composite membranes showed a high conductivity of 260 mS cm −1 even at 180°C, indicating that BN‐based membranes showed good perspective in the high‐temperature PEMFC application 197 .…”