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Electrical Behavior
Published in David W. Richerson, William E. Lee, Modern Ceramic Engineering, 2018
David W. Richerson, William E. Lee
Oxygen ion-conducting ceramics require relatively high temperature before the electrical conductivity is high enough for commercial applications. Sodium ion-conducting ceramics operate at lower temperature, as shown in Figure 10.12. Sodium ion conduction is the basis for a high-power-density (~200 W/kg) battery that has received intermittent development for automotive, utility load leveling, and satellite applications. The battery is referred to as the sodium/sulfur (Na/S) battery and was first announced in 1967 by Ford Motor Company. A simple schematic is shown in Figure 10.13. A thin-walled tube of an impervious sodium ion conductor separates molten sodium metal from molten sulfur. The most successful sodium ion conductor developed so far for the Na/S battery has been β″-alumina. At 300–350°C (570–660°F), sodium ions rapidly migrate through the β″-alumina solid electrolyte from the sodium side to the sulfur side. Each sodium atom that ionizes releases an electron that travels through an external circuit and provides an overall open circuit voltage of 2.08 V for a typical cell. Sodium ions that reach the sulfur side of the β″-alumina membrane combine with sulfur to form sodium polysulfide compounds. This represents the discharge cycle of the battery. An external voltage can be applied to the battery to force the polysulfides to dissociate and the Na ions to return to the molten sodium side of the electrolyte, resulting in recharge of the battery.
Synthesis of ethylene dichloride-based polysulfide polymers: investigation of polymerization yield and effect of sulfur content on solubility and flexibility
Published in Journal of Sulfur Chemistry, 2021
Milad Sheydaei, Saeid Talebi, Mehdi Salami-Kalajahi
Aqueous monomers were synthesized according to the procedure described in the literature [5,52]. Briefly, NaOH was dissolved in water and after rising temperature to its boiling point, elemental sulfur under the stoichiometry condition was added and the reaction was continued for 1 h. The mixture was cooled down to room temperature. Then, 50 mL sodium polysulfide (sodium sulfide, sodium disulfide, sodium trisulfide, and sodium tetrasulfide) solution was added to a 150-mL four-necked round bottom flask equipped with a stirrer, dropping funnel, condenser, and thermometer. The sodium polysulfide solution was stirred with constant stirring at 600 rpm and then, the flask was heated to 75°C, and subsequently 10 mL ethylene dichloride was gently added through a dropping funnel during 30 min. Afterward, the produced polymer was filtered and washed by distilled water and HCl to remove the inorganic salts. Finally, the product was vacuum-dried at 50°C for 24 h.
New insight into sulfur nanoparticles: Synthesis and applications
Published in Critical Reviews in Environmental Science and Technology, 2021
Shiv Shankar, Lily Jaiswal, Jong-Whan Rhim
Xie et al. (2009) prepared cystine-stabilized SNPs by liquid synthesis method using sublimed sulfur. They added cystine solution drop-wise to the sulfur ethanol saturated solution with ultrasonic treatment and obtained a cysteine-nanosulfur solution. The size of the cysteine-nanosulfur was about 50–100 nm. Xie et al. (2012) produced sulfur nanorods in the presence of solvent PEG-200 and reported the properties and mechanisms of sulfur nanorods and their formation. For this purpose, sublimed sulfur and PEG-200 were mixed together and heated at 125 °C for 1 h while refluxing to get saturated transparent yellow PEG-200 sulfur. Rapidly transfer the solution to ice water to produce a yellow suspension of nanosulfur-PEG solution. In this way, a homogeneous rod-like structure with a diameter of about 80 nm was obtained. Ghoraba et al. (2017) prepared SNPs in a liquid phase by grinding the sulfur powder, mixing it with water in a mortar, and adding solid sodium sulfite until the sulfur powder was completely dissolved to form polysulfide that was marked by the color change of the solution to orange-yellow. After adding polyethylene glycol (PEG-400) to the mixture, a solution containing hydrochloric acid and PEG-400 was slowly added to form light yellow nanoparticles in the solution. Massalimov et al. (2012) synthesized SNP from potassium polysulfide by treatment with various organic and inorganic acids. For the synthesis, the acid solution was mixed with a potassium polysulfide aqueous solution under constant stirring to precipitate the SNP. They also reported the synthesis of sulfur nanoparticles using sodium polysulfide solution. In another approach, Suleiman et al. (2015) synthesized SNP by an oxidation precipitation method using sodium thiosulfate and tetraoctyl ammonium bromide in the presence of concentrated HCl at 40 °C. This process provides highly crystalline pure sulfur nanoparticles of uniform shape and size.
Sodium sulfide-based polysulfide polymers: synthesis, cure, thermal and mechanical properties
Published in Journal of Sulfur Chemistry, 2022
The molecular weight of the samples and the effect of TBAB on the polymerization yield are reported in Table 1. The molecular weights were calculated by 1H NMR technique (Supporting Information Figure S1) using the peak area ratio of monomer to the polymer as reported in the literature [12–14]. The results reported in the literature show that in interfacial polymerization of polysulfide polymers, increasing the temperature leads to better mobility and a higher penetration rate of monomers at the interface and therefore increases the polymerization yield [13]. Therefore, the reaction temperature near to the boiling point of organic monomers was chosen. The choice of reaction temperature for poly(p-xylene sulfide) was for the same and comparable results with the other two reactions (poly(ethylene sulfide) and poly(butylene sulfide)). As can be seen, in the absence of TBAB only two of the reactions have a yield. The lack of yield is due to the intramolecular cyclization reaction that exists in addition to linear polymerization [13,19]. In the previous study, it was shown that the yield are associated to the number of carbons in the polymer structure, so that by increasing the number of carbon atoms from 1 to 2, the polymerization yield increases and by increasing the number to 4, polymer is not formed [19]. Here we can say that the presence of a six-membered ring in the monomer structure also prevents polymerization yield, and it probably shows that the increase in carbon and the presence of the ring cause rising in the intramolecular cyclization reaction [13,19,29]. It should be noted that the lack of yield occurs in the reaction of α,α′-dichloro-p-xylene with sodium sulfide because in reaction with other sodium polysulfide monomers (sodium disulfide and sodium tetrasulfide) the product is formed [22,37]. This is because the probability of intramolecular cyclization increases with a decrease in the monomer concentration [13]. Therefore, it can be said that here, with the decrease in monomer concentration and the presence of rings in the monomer; the intra-molecular cyclization reaction has increased to such an extension that the linear reaction is no longer performed. The results show that the addition of TBAB in the reaction media formed the product for poly(butylene sulfide) and poly(p-xylene sulfide) and also increased the polymerization yield for poly(methylene sulfide) and poly(ethylene sulfide). Further increase in TBAB concentration led to a decrease in yield (Supporting Information Table S1) because with the addition of more TBAB, the catalyst comes out of the organic and aqueous phases and becomes a distinct phase, and like a blocker, it reduces the access of the two phases to each other [13].