Polymer electrolyte membrane modification in direct ethanol fuel cells: An update

Jekal

et al. 2023

Gels

A facile oxygen (O2) atmospheric plasma treatment is applied to a polyvinyl alcohol (PVA) matrix to enhance its wettability and hydrophilicity. The optimal plasma treatment conditions are determined by varying the applied plasma power and plasma treatment time. A PVA matrix treated with a plasma power of 120 W for 5 s shows the most hydrophilicity owing to successful formation of carbonyl (–CO, >C=O) functional groups without any structural degradation. The plasma-treated PVA matrix is used as the gel-polymer electrolyte of a solid-state supercapacitor (SSC) by immersing solid matrix into various liquid electrolytes, such as sodium sulfate (Na2SO4), sulfuric acid (H2SO4), and potassium hydroxide (KOH). Compared with the pristine PVA-based device, PVA-120W5/Na2SO4-, PVA-120W5/H2SO4-, and PVA-120W5/KOH-based SSCs show 2.03, 2.05, and 2.14 times higher specific capacitances, respectively. The plasma-treated PVA matrix shows increased specific capacitance owing to the increased wettability, which in turn increases the ion transportation and reduces the electrical resistance. This study successfully demonstrates that the electrochemical performance of a SSC can be readily enhanced through plasma treatment for a short time (≤5 s).

Section: Introductionmentioning

confidence: 99%

Facile Enhancement of Electrochemical Performance of Solid-State Supercapacitor via Atmospheric Plasma Treatment on PVA-Based Gel-Polymer Electrolyte

Jekal

et al. 2023

Gels

J of Chemical Tech & Biotech

“…However, when the membrane is applied in a direct liquid fuel cell such as DEFC, fuel crossover problems have led to a decline in the single-cell performance of DEFC. [12][13][14] Therefore, our previous research has developed a filler from chicken eggshell material and used it in Nafion for direct methanol fuel cells (DMFC). 15 We found that chicken eggshells' main ingredient/compound is calcium carbonate (CaCO 3 ), and other researchers also support this finding.…”

Section: Introductionmentioning

confidence: 99%

“…Nafion membranes are commonly used in fuel cells because of their high proton conductivity. However, when the membrane is applied in a direct liquid fuel cell such as DEFC, fuel crossover problems have led to a decline in the single‐cell performance of DEFC 12‐14 . Therefore, our previous research has developed a filler from chicken eggshell material and used it in Nafion for direct methanol fuel cells (DMFC) 15 .…”

Section: Introductionmentioning

confidence: 99%

Calcium carbonate from chicken eggshells as filler in composite Nafion membrane for direct ethanol fuel cell: a molecular dynamics study

Karim

Alias

Shaari

et al. 2023

BACKGROUNDDirect ethanol fuel cells (DEFC) need fillers to mitigate the issue of ethanol crossing over from the anode to the cathode, which lowers performance. Therefore, this study developed calcium carbonate (CaCO3) from chicken eggshells as a filler in a Nafion composite membrane for DEFC. Three cluster models of CaCO3 filler were developed, namely (CaCO3)2, (CaCO3)3, and (CaCO3)4, to form the Nafion composite membranes. The properties of composite membranes, such as proton conductivity, ethanol permeability, and selectivity, were studied using the molecular dynamics method. In addition, the three main factors influencing the composite membranes’ properties were analyzed in this study; these were cluster size of CaCO3, mass loading of the filler, and ethanol concentration.RESULTSThe results show that filler has reduced proton conductivity and ethanol permeability in the DEFC application compared to the Nafion membrane. However, the selectivity is used as a trade‐off between ion conductivity and ethanol permeability in the composite membrane, thus requiring a suitable size structure and mass loading to balance the high ion conductivity rate and reduce the ethanol permeability rate. The composite membrane C‐(CaCO3)4, which has a large cluster size in this study, shows that it is necessary to restrict ethanol permeability at a high ethanol concentration of 5 mol L−1. However, the structure size in cluster B – (CaCO3)3 – can reduce ethanol permeability but requires high mass loading by 5 wt%. Analysis of variance showed significant values for ion conductivity, ethanol permeability, and selectivity responses.CONCLUSIONCaCO3 successfully reduced ethanol crossover in DEFC, with all three composite membranes being suitable for use at low ethanol concentrations. However, specific size structure and mass loading are required to overcome ethanol crossover at high ethanol concentration. © 2023 Society of Chemical Industry (SCI).

“…Among sustainable biofuels, ethanol is the most commonly adopted option worldwide, and as a renewable source, it offers zero net emissions . This is due to ethanol being economically viable, , easy to produce, and non-toxic, and it can be obtained from various crops and vegetable waste. , Additionally, instead of being burned, ethanol can be converted straight to electricity using ethanol-based fuel cells, − based on research conducted to improve the efficiency of such devices. ,− …”

Section: Introductionmentioning

confidence: 99%

Adsorption of Ethanol, Water, and Ethanol–Water Dimers on Open-Ended Graphene Capillaries Studied by Ab Initio Methods: Unraveling the Ethanol and Water Attachment at the Edges

2023

This ab initio study evaluated the interaction of ethanol, water, and ethanol–water dimers with an open-ended graphene capillary (GC). The results for a 10 Å GC showed that the ethanol stability on the surface depends on the molecule orientation within the structure and its position along the GC cross-section. The vertically oriented adsorbed ethanol finds the most stable site at the GC edges. However, when the ethanol lies on the surface, it is more stable at the GC center. In contrast, the water molecules are more stable at the GC edge. The analysis shows that the vertically aligned molecule presents a stronger ethanol–GC bond at the edge, with enhanced covalent characteristics. This holds for GCs with different widths but is modified as a function of the interlayer separation (d). For d larger than ∼12 Å the ethanol laying on the GC center becomes favorable, as well as the vertically oriented molecule laying on the surface at ∼7 Å. As single molecules, ethanol and water receive charges, but upon dimer formation, ethanol donates and water gains. Interestingly, the ethanol–GC covalent bond enhances while it decreases for water–GC in the dimer, compared to the single molecule adsorption. These results clarify the ethanol–water/GC interaction.