The Role of the Anion in Concentrated Electrolytes for Lithium-Sulfur Batteries
Journal article, 2024
Highly concentrated electrolytes show promise in enhancing lithium-sulfur (Li-S) battery performance by mitigating polysulfide (PS) solubility. The role of the salt anion for the performance improvement(s) is however not well understood. Here a systematic characterization using (concentrated) electrolytes based on three different salts: LiTFSI, LiTf, and LiTDI, in a common DOL:DME solvent mixture is reported for a wide range of physicochemical and electrochemical properties: ionic conductivity, density, viscosity, speciation, and PS solubility. While increased salt concentration in general improves Li-S battery performance, the role of the salt anion introduces complexity. The 2 m LiTDI-based electrolyte, with a slightly higher viscosity and lower PS solubility, outperforms the LiTFSI-based counterpart in terms of accessible reversible capacity. Conversely, the 2 m LiTf-based electrolyte exhibits subpar performance due to the formation of ionic aggregates that renders more free solvent and, therefore higher PS solubility, which, however can be improved by using a 5 m concentrated electrolyte. Hence, using electrolyte salt concentration as a rational design route demands an understanding of the local molecular structure, largely determined/affected by the choice of anion, as well as how it connects to the global properties and in the end improved Li-S battery performance.
highly concentrated electrolytes
lithium-sulfur batteries
high-performance liquid chromatography
COSMO-RS
role of the anion
Author
Aginmariya Kottarathil
Chalmers, Physics, C3SE
Warsaw University of Technology
Alistore - European Research Institute
Zaher Slim
Chalmers, Physics, Materials Physics
Hafiz Ahmad Ishfaq
National Institute of Chemistry
Alistore - European Research Institute
Chalmers, Physics, C3SE
Steffen Jeschke
Griffith University
G. Z. Zukowska
Warsaw University of Technology
Maciej Jozef Marczewski
Warsaw University of Technology
Katarzyna Lech
Warsaw University of Technology
Patrik Johansson
Chalmers, Physics, Materials Physics
Alistore - European Research Institute
W Wieczorek
Alistore - European Research Institute
Warsaw University of Technology
Journal of the Electrochemical Society
0013-4651 (ISSN) 1945-7111 (eISSN)
Vol. 171 7 070506Electrolytes for Metal-Organic Multivalent Batteries
Swedish Energy Agency (50638-1), 2021-01-01 -- 2024-12-31.
Swedish Research Council (VR) (2020-03988), 2021-01-01 -- 2024-12-31.
Next Generation Batteries
Swedish Research Council (VR) (2021-00613), 2021-12-01 -- 2032-12-31.
Subject Categories
Inorganic Chemistry
Physical Chemistry
Materials Chemistry
Condensed Matter Physics
DOI
10.1149/1945-7111/ad5b8c