Thermal reactivity of three lithiated carbonaceous materials

Abstract

The thermal stabilities of hard carbon spherule (HCS), artificial graphite (AG), and natural graphite (NG) were investigated by thermo-gravimetric differential scanning calorimetry (TG-DSC). After lithiation, AG shows the lowest onset exothermic temperature. However, all there materials exhibit similar onset temperatures for thermal reactions after ten cycles. It is obvious that the thermal behaviors of solid electrolyte interphase (SEI) film for HCS and AG change gradually with the electrochemical cycling. In contrast, the thermal stability of the surface film on NG is maintained during repeated lithium ion insertion/extraction. Because of their different Li storage behaviors, their thermal reactivities with electrolyte are quite different from each other. Especially for HCS, it shows several successive and different exothermic peaks at the 1st and 11th lithiated states, while both AG and NG display similar thermal reactivity before and after repeated cycles. In summary, it is found that thermal properties of SEI layer and lithium in lithiated carbonaceous materials for all three samples have different impacts on the whole thermal behaviors of electrode.

Facile controlled growth of silica on carbon spheres and their superior electrochemical properties

“…It is expected that the electrochemical properties of carbon spheres can be also enhanced by this crystallized silica coating layer. [27][28][29][30][31][32] These functional groups are probably attributed to the residual dangling bond, absorbed water, and air molecules. After silica coating, extra vibration bands located at 1166, 799, 780, 696, 521, 467 and 397 cm 21 can be observed in Fig.…”

The Effect of Key Electronic States on Excess Lithium Intercalation in Li2ruymn1-Yo3

“…The 1T phase finally disappear at 0.4 V, indicating the typical conversion reaction at this stage. 1,[4][5][6] In this study, we focus our attention on the intercalation reaction. Similarly, the emergence of 1T phase at lower angle indicates the two-phase reaction process above 0.8 V. V, 2.0-4.6 V, and 1.0-4.5 V at a current density of 30 mA g -1 .…”