Molecular structure and stability of dissolved lithium polysulfide species

被引：216

作者：

Vijayakumar, M. ^{[1
]}

Govind, Niranjan ^{[1
]}

Walter, Eric ^{[1
]}

Burton, Sarah D. ^{[1
]}

Shukla, Anil ^{[1
]}

Devaraj, Arun ^{[1
]}

Xiao, Jie ^{[1
]}

Liu, Jun ^{[1
]}

Wang, Chongmin ^{[1
]}

Karim, Ayman ^{[1
]}

Thevuthasan, S. ^{[1
]}

机构：

[1] Pacific NW Natl Lab, Richland, WA 99352 USA

来源：

PHYSICAL CHEMISTRY CHEMICAL PHYSICS | 2014年 / 16卷 / 22期

关键词：

DENSITY-FUNCTIONAL THEORY; LIQUID ELECTROLYTES; SULFUR BATTERIES; GRAPHENE OXIDE; RADICAL-ANION; CARBON PAPER; BASIS-SET; PERFORMANCE; CHEMISTRY; MECHANISM;

D O I：

10.1039/c4cp00889h

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

The ability to predict the solubility and stability of lithium polysulfide is vital in realizing longer lasting lithium-sulfur batteries. Herein we report combined experimental and computational analyses to understand the dissolution mechanism of lithium polysulfide species in an aprotic solvent medium. Multi-uclear NMR, variable temperature ESR and sulfur K-edge XAS analyses reveal that the lithium exchange between polysulfide species and solvent molecules constitutes the first step in the dissolution process. Lithium exchange leads to de-lithiated polysulfide ions (S-n(2-)) which subsequently form highly reactive free radicals through dissociation reaction (S-n(2-) -> 2S(n/2)(center dot-)). The energy required for the dissociation and possible dimer formation reactions of the polysulfide species is analyzed using density functional theory (DFT) based calculations. Based on these findings, we discuss approaches to optimize the electrolyte in order to control the polysulfide solubility.

引用

页码：10923 / 10932

页数：10

共 59 条

[1] Lithium/Sulfur Cell Discharge Mechanism: An Original Approach for Intermediate Species Identification [J].