A tailored highly solvating electrolyte toward ultra lean-electrolyte Li–S batteries
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 d...
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| Main Authors: | , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Tsinghua University Press
2024-12-01
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| Series: | Nano Research Energy |
| Subjects: | |
| Online Access: | https://www.sciopen.com/article/10.26599/NRE.2024.9120126 |
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| Summary: | 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. |
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| ISSN: | 2791-0091 2790-8119 |