Lithium polysulfide solvation and speciation in the aprotic lithium-sulfur batteries (Open Access)--颗粒学报PARTICUOLOGY

Zhang, J., Fu, Q., Li, P., Linghu, R., Fan, X., Lin, H., . . . Kong, L. (2024). Lithium polysulfide solvation and speciation in the aprotic lithium-sulfur batteries. Particuology, 89, 238-245. https://doi.org/10.1016/j.partic.2023.11.006

Lithium polysulfide solvation and speciation in the aprotic lithium-sulfur batteries (Open Access)

Jinhao Zhang^{a 1}, Qingshan Fu^{a 1}, Peng Li^b, Ruibo Linghu^a, Xiaozhong Fan^a, Haibin Lin^c, Juncao Bian^c, Songbai Han^c *, Gengzhi Sun^d *, Long Kong^a *

a Frontiers Science Center for Flexible Electronics and Xi’an Institute of Flexible Electronics, Northwestern Polytechnical University, Xi’an, 710129, China
b China Automotive Innovation Corporation, Nanjing, 211100, China
c Academy for Advanced Interdisciplinary Studies, Southern University of Science and Technology, Shenzhen, 518055, China
d Institute of Advanced Materials, Nanjing Tech University, Nanjing, 211816, China

10.1016/j.partic.2023.11.006

Volume 89, June 2024, Pages 238-245

Received 14 October 2023, Revised 6 November 2023, Accepted 7 November 2023, Available online 17 November 2023, Version of Record 14 December 2023.

E-mail: hansb@sustech.edu.cn; iamgzsun@njtech.edu.cn; iamlkong@nwpu.edu.cn

Highlights

• Sulfur speciation in the conventional electrolyte composition is discussed.

• Thermodynamic and transport properties are used to rationalize electrolyte formulation.

• The term coordination strength is employed to describe LiPS solvation.

• The chelating effect is identified as a critical descriptor to define LiPS structure.

Abstract

Fingerprinting sulfur speciation in aprotic electrolytes is a key to understand fundamental chemistry and design well-performing lithium–sulfur (Li–S) batteries. Lithium polysulfide (LiPS) dissolution and deposition in ether-based electrolytes during redox reactions have been probed and established by spectroscopy and microscopy. However, detailed LiPS structure and solvation properties influenced by conventional and newly developed electrolytes remain elusive, which exert fundamental challenges and practical difficulties in decoupling battery performance from electrolyte volume. This perspective aims to provide timely information to uncover underlying mechanisms that rein in sulfur speciation by considering the charge density of LiPSs and the coordination strength of solvents/salts. The discussion starts with unlocking the baseline electrolyte formulation to investigate its role in LiPS formation and compatibility. After that, the term coordination strength is used instead of donor number and dielectric constant to describe interactions between solvents and LiPSs and to reveal LiPS structure evolution. This work is expected to encourage the discovery of new electrolyte working mechanisms to develop energy-dense and power-intensive Li–S batteries.

Graphical abstract

Keywords

Sulfur speciation; Redox kinetics; Coordination strength; Solvation chemistry; Lithium–sulfur batteries

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