In-situ UV-Vis Spectroscopy of Trisulfur Radicals in Lithium-Sulfur Batteries
Renju Dou, Qin Wang, Xiaoyan Ren, Lehui Lu
In-situ UV-Vis Spectroscopy of Trisulfur Radicals in Lithium-Sulfur Batteries
Here we employ in-situ UV-Vis spectroscopy to monitor the sulfur redox reaction with oxygen-containing molecules as an additive, for example, biphenyl-4,4′-dicarboxylic acid (BDC). Furthermore, Raman spectrum, electron paramagnetic resonance (EPR), and electrospray ionization-mass spectrometry (ESI-MS) measurements reveal that the formation of BDC-S3 •‒ complexes can establish the long-term stability of polysulfide radicals, change the kinetics of sulfur redox reaction, and then generate decent capacity retention and rate capability. According to the density functional theory (DFT) analysis, S3 •‒ radicals are the underlying product of S6 2‒ cleavage, owing to the decreased chemical energy and the increased stability of S3 •‒ radicals through Lewis acid-base interaction. The assembled Li-S batteries with BDC additive deliver a high reversible capacity of 420 mA·h·g−1 over 200 cycles with over 98% Coulombic efficiency, under the current density of 0.2 C.
Radical / Polysulfide / In-situ UV-Vis Spectroscopy / Electrolyte additive / Lithium-sulfur battery
[[1]] |
|
[[2]] |
|
[[3]] |
|
[[4]] |
|
[[5]] |
|
[[6]] |
|
[[7]] |
|
[[8]] |
|
[[9]] |
|
[[10]] |
|
[[11]] |
|
[[12]] |
|
[[13]] |
|
[[14]] |
|
[[15]] |
|
[[16]] |
|
[[17]] |
|
[[18]] |
|
[[19]] |
|
[[20]] |
|
[[21]] |
|
[[22]] |
|
[[23]] |
|
[[24]] |
|
[[25]] |
|
[[26]] |
Frisch M. J., Gaussian 09, Gaussian Inc., 2009
|
[[27]] |
|
[[28]] |
|
[[29]] |
|
[[30]] |
|
[[31]] |
|
[[32]] |
|
[[33]] |
|
[[34]] |
|
[[35]] |
|
[[36]] |
|
/
〈 | 〉 |