Constructing Proton Transfer Channels Using CuO Nanowires and Nanoparticles as Porogens in High-Temperature Proton Exchange Membranes

Abstract

Constructing proton-transfer channels is considered as an efficient method to improve the performance of cross-linked phosphoric acid (PA)-doped polybenzimidazoles’ membranes. In this study, copper­(II) oxide nanowires and nanoparticles are used for the first time as porogens to construct different proton-transfer channels in a high-temperature membrane. Membranes with different porous structures are successfully prepared. The results indicate that the successful construction of continuous porous proton-transfer channel makes positive contributions to improve the performances of a membrane fuel cell. Among them, a continuous proton-transfer channel (continuous pore structure) can be constructed at a lower porogen content using nanowires (which is indicated in the change of conductivity at the ratio of 3:10). Using nanowires also can enable constructing a more effective proton-transfer channel at the same porogen content (at the ratio of 5:10) than using nanoparticles. However, the increase of porogen content is not conducive to the stability of PA retention. The KH560 cross-linked membrane (3:10W-0.01KH560) achieves excellent comprehensive performances. The results indicate that the membranes prepared using nanowires are promising for actual use in high-temperature proton exchange membrane fuel cells.

Achieving 1060 mW cm−2 with 0.6 mg cm−2 Pt Loading Based on Imidazole‐Riched Semi‐Interpenetrating Proton Exchange Membrane at High‐Temperature Fuel Cells

“…The gel ratio of the PEM after the test was measured and shown in Table S1 (Supporting Information). Compared to the sIPN structure HT-PEM [44,45] and PBI composited membranes [20,23,28,31,[63][64][65][66][67][68][69] that reported recently (Table 2), the sIPN membrane PBI-VED displays superior conductivity and fuel cell performance. The performance improvement is contributed by the enhanced PA uptake.…”

“…The possible reason could be the micro-porous structure of the PBI-V membrane. [23,27,31,60] As we discussed in Section 2.1, low-molecular-weight PVIm in PBI-VED-57% are removed during the post-purification process. It can be inferred that micro-pores are left in the purified membrane, and micro-porous structures can be detected by SEM (Figure 3a).…”

“…[23,24] Lu et al reported a porous PEM with a dense skin layer, achieving an ADL of 14.5, which resulted in excellent proton conductivity of 0.112 S cm −1 . [25] In addition, the creation of proton transport channels with materials such as metal-organic frameworks (MOF), [26,27] Pillar [5]arene, [18] hydrogels, [28,29] Tröger's base, [3,24,30] or nanowires [31] represent efficient approaches for promoting proton conduction. However, the excessively high PA uptake will present significant drawbacks: i) degradation of mechanical strength, ii) acid leakage reducing oxygen diffusivity, and iii) impaired cathodic oxygen reduction reaction (ORR) kinetics.…”

Enhancing Performance and Stability of High-Temperature Proton Exchange Membranes through Multiwalled Carbon Nanotube Incorporation into Self-Cross-Linked Fluorenone-Containing Polybenzimidazole

“…High-temperature proton exchange membrane (HT-PEM) fuel cells (HT-PEMFCs), operating above 120 °C, have garnered extensive research attention due to their superior carbon monoxide (CO) tolerance and simplified hydrothermal management. − The PEM plays a pivotal role in HT-PEMFCs, employing various polymers for this purpose. ,− Notably, sulfonated polyetheretherketone, − polybenzimidazole (PBI), − sulfonated polysulfone, and poly­(vinyl alcohol) (PVA) are among the majorly studied PEMs. Phosphoric acid (PA)-doped PBI membranes stand out as a particularly promising system for HT-PEMFCs, owing to their remarkable thermal stability, PA stability, aging resistance, and modifiable polymer backbone. − The proton conductivity of PA-doped PBI membranes directly correlates with their PA content, influencing proton transport through PA hydrogen-bond networks.…”