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Research Article | Open Access | Online First

A tailored highly solvating electrolyte toward ultra lean-electrolyte Li–S batteries

Zixiong Shi1, Simil Thomas2, Zhengnan Tian1, Dong Guo1, Zhiming Zhao1, Yizhou Wang1, Shuo Li1, Nimer Wehbe3, Abdul-Hamid Emwas3, Osman M. Bakr1, Omar F. Mohammed2, Husam N. Alshareef1( )
Materials Science and Engineering, Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
Advanced Membranes and Porous Materials Center (AMPMC), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
Core Labs, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
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Abstract

Low electrolyte usage is a key to attaining high-energy-density lithium–sulfur (Li–S) batteries. However, this is still a tremendous challenge for traditional ether-based electrolytes that follow a dissolution–precipitation mechanism. Highly solvating electrolytes, which can facilitate polysulfide dissolution and alter reaction pathway, are considered a promising strategy. Nonetheless, mechanistic understanding and kinetic evaluation remain insufficient while the principle of Li2S nucleation and dissociation has not been elucidated. Herein, we unveil the Li-ion solvation and polysulfide speciation in the solvents with different denticity and donicity. The origin of S3•– radical-directed path and three-dimensional Li2S precipitation in high-donicity electrolytes has been uncovered. It is revealed that ammonium ions enable the facile dissolution and dissociation of Li2S via Lewis acid-base interaction and H···S2– binding. Consequently, Li–S batteries with a low electrolyte and sulfur (E/S) ratio of 5 μL·mgs–1 achieve a high capacity of 1092 mAh·g–1. Even at a harsh E/S ratio of 3 μL·mgs–1 and a high sulfur loading of 4 mg·cm–2, they still sustain a stable operation over 30 cycles. Our work sheds light on the underlying reaction mechanism and rationalizes the design of highly solvating electrolytes, which in turn opens a new avenue for achieving pragmatic lean-electrolyte Li–S batteries.

Keywords

donicityS3•– radicalLi2S dissociationlean-electrolyteLi–S batteries

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Nano Research Energy
DOI: 10.26599/NRE.2024.9120126
Cite this article:
Shi Z, Thomas S, Tian Z, et al. A tailored highly solvating electrolyte toward ultra lean-electrolyte Li–S batteries. Nano Research Energy, 2024, https://doi.org/10.26599/NRE.2024.9120126

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Received: 20 March 2024
Revised: 07 April 2024
Accepted: 09 May 2024
Published: 29 May 2024
© The Author(s) 2024. Published by Tsinghua University Press.

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