Dehydrofluorination Process of Poly(vinylidene difluoride) PVdF-Based Gel Polymer Electrolytes and Its Effect on Lithium-Sulfur Batteries
View/ Open
Date
2023-04-14Author
Castillo Ruiz de Azua, Julen
Robles Fernández, Adrián
Cid Barreno, Rosalía
González Marcos, José Antonio
Armand, Michel
Carriazo, Daniel
Zhang, Heng
Santiago Sánchez, Alexander
Metadata
Show full item record
Gels 9(4) : (2023) // Article ID 336
Abstract
Gel polymer electrolytes (GPEs) are emerging as suitable candidates for high-performing lithium-sulfur batteries (LSBs) due to their excellent performance and improved safety. Within them, poly(vinylidene difluoride) (PVdF) and its derivatives have been widely used as polymer hosts due to their ideal mechanical and electrochemical properties. However, their poor stability with lithium metal (Li0) anode has been identified as their main drawback. Here, the stability of two PVdF-based GPEs with Li0 and their application in LSBs is studied. PVdF-based GPEs undergo a dehydrofluorination process upon contact with the Li0. This process results in the formation of a LiF-rich solid electrolyte interphase that provides high stability during galvanostatic cycling. Nevertheless, despite their outstanding initial discharge, both GPEs show an unsuitable battery performance characterized by a capacity drop, ascribed to the loss of the lithium polysulfides and their interaction with the dehydrofluorinated polymer host. Through the introduction of an intriguing lithium salt (lithium nitrate) in the electrolyte, a significant improvement is achieved delivering higher capacity retention. Apart from providing a detailed study of the hitherto poorly characterized interaction process between PVdF-based GPEs and the Li0, this study demonstrates the need for an anode protection process to use this type of electrolytes in LSBs.
Collections
Except where otherwise noted, this item's license is described as © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/ 4.0/).