Swelling-Resistant, Crosslinked Polyvinyl Alcohol Membranes with High ZIF-8 Nanofiller Loadings as Effective Solid Electrolytes for Alkaline Fuel Cells

Abstract

The present work investigates the direct mixing of aqueous zeolitic imidazolate framework-8 (ZIF-8) suspension into a polyvinyl alcohol (PVA) and crosslinked with glutaraldehyde (GA) to form swelling-resistant, mechanically robust and conductivity retentive composite membranes. This drying-free nanofiller incorporation method enhances the homogeneous ZIF-8 distributions in the PVA/ZIF-8/GA composites to overcome the nanofiller aggregation problem in the mixed matrix membranes. Various ZIF-8 concentrations (25.4, 40.5 and 45.4 wt.%) are used to study the suitability of the resulting GA-crosslinked composites for direct alkaline methanol fuel cell (DAMFC). Surface morphological analysis confirmed homogeneous ZIF-8 particle distribution in the GA-crosslinked composites with a defect- and crack-free structure. The increased ionic conductivity (21% higher than the ZIF-free base material) and suppressed alcohol permeability (94% lower from the base material) of PVA/40.5%ZIF-8/GA resulted in the highest selectivity among the prepared composites. In addition, the GA-crosslinked composites’ selectivity increased to 1.5–2 times that of those without crosslink. Moreover, the ZIF-8 nanofillers improved the mechanical strength and alkaline stability of the composites. This was due to the negligible volume swelling ratio (<1.4%) of high (>40%) ZIF-8-loaded composites. After 168 h of alkaline treatment, the PVA/40.5%ZIF-8/GA composite had almost negligible ionic conductivity loss (0.19%) compared with the initial material. The maximum power density (Pmax) of PVA/40.5%ZIF-8/GA composite was 190.5 mW cm−2 at 60 °C, an increase of 181% from the PVA/GA membrane. Moreover, the Pmax of PVA/40.5%ZIF-8/GA was 10% higher than that without GA crosslinking. These swelling-resistant and stable solid electrolytes are promising in alkaline fuel cell applications.

Synthesis and Characterization of PVA-Enzyme/GA/PPy/ PVC-KTpClPB-o-NPOE Indicator Electrodes, XRD Analysis, FTIR and Variable Signal Analysis

“…The GA-crosslinked composite increased ionic conductivity (Hsu, 2022), the phase purity of the PVA/GA and PVA/ZIF-8/GA composites was determined using X-ray diffraction. The chemical structure of the sample was determined using Fourier transform infrared spectroscopy.…”

Synthesis and study of enhanced electrochemical properties of NiO nanoparticles deposited on TiO2 nanotubes

“…Nonetheless, anti-electrolytes based fuel cells modules have many extensions since energy units dependent on acidic electrolytes work principally with Pt-based catalysts and this reliance makes them more costly. [22][23][24][25][26][27][28] Anyway, the AFCs can work with moderately more affordable metals, for example, Au, Ag, and Ni. There are many benefits related to the AFCs, which make them more practical to make than acidic electrolytes-based energy fuel cells.…”

“…There are many benefits related to the AFCs, which make them more practical to make than acidic electrolytes-based energy fuel cells. [22][23][24][25] Figure 1 shows the schematic of an alkaline fuel cell where the charge transporters are hydroxyl particles that relocate from cathode to anode where the reaction with hydrogen produces water and electrons.…”

“…There are many benefits related to the AFCs, which make them more practical to make than acidic electrolytes‐based energy fuel cells. [ 22–25 ]…”