Issue 20, 2019

Akin solid–solid biphasic conversion of a Li–S battery achieved by coordinated carbonate electrolytes

Abstract

Lithium–sulfur batteries are of significant interest because their theoretical energy density exceeds that of Li-ion batteries and they can be fabricated at much lower costs. Although significant efforts have been devoted towards improving sulfur electrodes, the battery requires a “flooded” electrolyte for the dissolution–precipitation chemistry to achieve acceptable energy efficiency (the electrolyte/sulfur ratio, E/S ratio, is typically much higher than 5 : 1 μl mg−1). Herein, we report a complex electrolyte of LiTFSI salt with widely used carbonate solvents (EC and DEC) other than ether (DOL and DME) for use in Li–S batteries based on S8 as the active material. By tuning the electrolyte coordination structure, we demonstrated that the sulfur speciation pathway was fundamentally altered from the conventional dissolution–precipitation category to an akin solid–solid biphasic conversion, leading to low E/S ratios and no shuttle effect. Furthermore, the reduced reactivity of the fully coordinated solvents mitigates Li dendritic formation and related electrolyte consumption. These combined merits allow us to demonstrate that a S8/Ketjenblack electrode can achieve a capacity close to theoretical capacity (1600 mA h g−1) and high coulombic efficiency (above 99%) with a stable cycling performance at an ultralow electrolyte/sulfur ratio (1.5 : 1 μl mg−1); hence, our study defines a new pathway towards the fabrication of highly robust Li–S batteries for high-density energy storage.

Graphical abstract: Akin solid–solid biphasic conversion of a Li–S battery achieved by coordinated carbonate electrolytes

Supplementary files

Article information

Article type
Paper
Submitted
16 Mar 2019
Accepted
23 Apr 2019
First published
24 Apr 2019

J. Mater. Chem. A, 2019,7, 12498-12506

Akin solid–solid biphasic conversion of a Li–S battery achieved by coordinated carbonate electrolytes

F. Huang, L. Gao, Y. Zou, G. Ma, J. Zhang, S. Xu, Z. Li and X. Liang, J. Mater. Chem. A, 2019, 7, 12498 DOI: 10.1039/C9TA02877C

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements