PDF Publication Title:
Text from PDF Page: 200
capacitance is known to be in the range of 1 – 10 μF cm-2,249 therefore our values do not match this range, and this semicircle cannot be correlated only to the charge transfer reactions on Li. More likely is that the LF semicircle could rather originate from a diffusion process through passivation layer(s) on Li surface, i.e. inner and outer deposited layer249. Our capacity values (range of ~ 10-3 F cm-2) are in complete agreement with report of Woo et al.249, who studied symmetrical Li||Li cell degradation. We have shown that the metallic lithium electrode significantly contributes to the initial impedance response of the Li/S cell, mainly through its passivation layer. Moreover, the resistance value is strongly related with the initial state of the lithium surface. Figure 6-4a shows some examples of symmetric Li||Li cells, where Li was used as-received, or when its surface was cleaned out by scratching with the Teflon®-made knife. Furthermore, this interface ages due to well-known passivation reactions, giving a rise to the significant increase of the semicircle amplitude (Figure 6-4b). It can be noticed that the resistance of the passivation layer varies between ~ 60 Ω (for ‘scratched’ surface) up to even 320 Ω (when left during few hours upon storage). (a) (b) Figure 6-4. Symmetric Li||Li coin cells: three different cells showing the influence of metallic Li surface, thus resulting in large variations of the resistance value at the initial state (a); evolution of a Nyquist plot upon Li||Li cell storage (b). It is very important to take these findings into consideration, especially during interpretation of the EIS spectra evolution upon cycling. Until now, most of the EIS-related studies of Li/S cell have completely neglected the fact of observing lithium negative electrode in such large extent, and even interpreting the MF semicircle as a charge transfer resistance of the positive electrode. Chapter 6: EIS and low temperature studies 196PDF Image | Accumulateur Lithium Soufre
PDF Search Title:
Accumulateur Lithium SoufreOriginal File Name Searched:
WALUS_2015_archivage.pdfDIY PDF Search: Google It | Yahoo | Bing
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
CONTACT TEL: 608-238-6001 Email: greg@infinityturbine.com (Standard Web Page)