Surfactant-Assisted Perovskite Nanofillers Incorporated in Quaternized Poly (Vinyl Alcohol) Composite Membrane as an Effective Hydroxide-Conducting Electrolyte

Abstract

Perovskite LaFeO 3 nanofillers (0.1%) are incorporated into a quaternized poly(vinyl alcohol) (QPVA) matrix for use as hydroxide-conducting membranes in direct alkaline methanol fuel cells (DAMFCs). The as-synthesized LaFeO 3 nanofillers are amorphous and functionalized with cetyltrimethylammonium bromide (CTAB) surfactant. The annealed LaFeO 3 nanofillers are crystalline without CTAB. The QPVA/CTAB-coated LaFeO 3 composite membrane shows a defect-free structure while the QPVA/annealed LaFeO 3 film has voids at the interfaces between the soft polymer and rigid nanofillers. The QPVA/CTAB-coated LaFeO 3 composite has lower methanol permeability and higher ionic conductivity than the pure QPVA and QPVA/annealed LaFeO 3 films. We suggest that the CTAB-coated LaFeO 3 provides three functions to the polymeric composite: increasing polymer free volume, ammonium group contributor, and plasticizer to enhance the interfacial compatibility. The composite containing CTAB-coated LaFeO 3 results in superior cell performance. A maximum power density of 272 mW cm −2 is achieved, which is among the highest power outputs reported for DAMFCs in the literature.

Highly Zeolite-Loaded Polyvinyl Alcohol Composite Membranes for Alkaline Fuel-Cell Electrolytes

“…Several anion-exchange polymeric membranes [ 15 , 16 ] or hydroxide-conductive electrolytes (alkaline-doped neutral membranes) [ 12 , 17 ] offer cost advantages compared to the proton-exchange membranes. Polyvinyl alcohol (PVA) is an inexpensive polymer with an excellent film-forming ability [ 5 ] used in membrane separation [ 18 ], as a fuel-cell electrolyte [ 19 ] and in biological applications [ 20 ].…”

Technical and Economic Analysis of Fuel Cells for Forklift Applications

“…While PEMFCs can already meet DOE’s 2020 targets of catalyst loading and power density, 15 only very few lab-scale DMFC experiments can get close to DOE’s target performance. 16 , 17 In addition, there is limited regulation or research on the lifetime of DMFCs. 10 , 18 For simplicity of comparison, this study assumes that DMFCs have the same 10-year lifetime as PEMFCs and uses model-simulated performance as the target performance of DMFCs.…”

“…This study uses the performance of the state-of-the-art PEMFC and DMFC tested under 80 °C and air with 50 kPa backpressure ( Figure 3 a) as the baseline performance. 17 , 33 Cell voltage, power density, and efficiency as functions of the operating current density are derived based on these performance data. The following voltage equations are applied to describe the voltage of the fuel cell at a given current density, i where R u is the universal gas constant, 8.314 J/mol/K; F is the Faraday constant, 96485 C/mol; and T is the operating temperature of the fuel cell, 80 °C.…”

A review of quaternized polyvinyl alcohol as an alternative polymeric membrane in DMFCs and DEFCs

“…The maximum power density of active DMFCs achieved 98.6 mW cm −2 by using the QPVA/5wt.%FS with 2 M methanol and 6 M KOH, whereas the maximum power density of active DEFCs achieved 79 mW cm −2 by using the QPVA/5wt.%FS with 3 methanol and 5 M KOH at 80°C. Moreover, Rajesh Kumar et al introduced perovskite LaFeO 3 that is combined with QPVA‐based membrane. The perovskite LaFeO 3 was functionalized with cetyltrimethylammonium bromide (CTAB) and synthesized with QPVA/CTAB‐coated perovskite LaFeO 3 membrane.…”

“…Therefore, optimum water absorption is required to stabilize the requirement of ionic conductivity and avoid swelling issues . Although the introduction of the quaternary ammonium group that is grafted to the PVA matrix polymer is beneficial for enhancing ionic conductivity, the functional group of QPVA‐based membrane increased the water‐absorbing property, thereby degrading the properties and performance of the cells . The phenomena of water uptakes happened when the hydrophilic region of QPVA‐based membrane continuously absorbs the water molecules and fills the interior space of the membrane.…”