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our further studies. Sulfur electrodes of even higher loadings (~ 10 – 12 mgSulfur cm-2) were prepared as well, and their cycling performances were investigated. For some of the experiments (before optimization of the preparation method, as shown on Figure 3-2), the Ø 14 mm electrode disks were punched out after the ink was coated on complete NwC sheet. Such electrodes were burdened with an error of imprecise collector weight. In that case, theoretical capacity is based on estimated sulfur mass only, with the possible deviation indicated, and the results are rather presented in respect to the obtained areal capacities (mAh cm-2). b) A binder-free electrode with melted sulfur (so-called ‘S-melted-NwC’). There are several methods described in the literature concerning sulfur infiltration into carbon structures131,227. We used a simple sulfur powder melting route, as reported to be an easy and efficient way to deposit sulfur on a carbon surface131. In order to prepare the electrode, as- received S8 powder was first gently grinded in the mortar, then dispersed on the NwC Ø 14 mm disk of known mass, and placed on the hot plate surface until all sulfur got melted. The heating process took less than 1 minute, since the hot plate was preheated up to ~ 150°C and sulfur rapidly diffused into the NwC layer thanks to good S/C interactions. After that, the mass of NwC+S8 disk was verified again and precise amount of sulfur was calculated. Such prepared electrode was then tested in a coin cell (fabrication already described in section 2.2.2). 3.2.1. The effect of imprecise NwC collector mass estimation and related capacity error Having such large imprecision of NwC Ø 14 mm (± 1 mg) due to its inhomogeneity, it was mandatory to verify the error related to the NwC mass, which may strongly affect the final capacity values. Taking into consideration a composite electrode ‘S-on-NwC’ with total weight of 23.000 mg, where the mass of NwC current collector is not precisely known but only estimated to be 14.7 ± 1 mg, the uncertainty of the theoretical capacity (∆Capacity) can be as high as 12.7 %, according to the equation (5) in Table 3-2. This error could indeed be detected on electrochemical profiles as well, as shown on Figure 3-3. In black, cycling curve based on precisely known active mass (AM) is shown. Red and blue dashed curves illustrate the cases when the active mass is overestimated and underestimated respectively, due to the imprecise weight of NwC. Chapter 3: S8 electrode on NwC 74PDF Image | Accumulateur Lithium Soufre
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Sulfur Deposition on Carbon Nanofibers using Supercritical CO2 Sulfur Deposition on Carbon Nanofibers using Supercritical CO2. Gamma sulfur also known as mother of pearl sulfur and nacreous sulfur... More Info
CO2 Organic Rankine Cycle Experimenter Platform The supercritical CO2 phase change system is both a heat pump and organic rankine cycle which can be used for those purposes and as a supercritical extractor for advanced subcritical and supercritical extraction technology. Uses include producing nanoparticles, precious metal CO2 extraction, lithium battery recycling, and other applications... More Info
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