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Electronic changes in poly(3,4-ethylenedioxythiophene)-coated LiFeSO4F during electrochemical lithium extraction

Blidberg, Andreas, Valvo, Mario, Alfredsson, Maria, Tengstedt, Carl, Gustafsson, Torbjörn, Björefors, Fredrik (2019) Electronic changes in poly(3,4-ethylenedioxythiophene)-coated LiFeSO4F during electrochemical lithium extraction. Journal of Power Sources, 418 . pp. 84-89. ISSN 0378-7753. (doi:10.1016/j.jpowsour.2019.02.039)

Abstract

The redox activity of tavorite LiFeSO4F coated with poly (3,4-ethylenedioxythiophene), i.e. PEDOT, is investigated by means of several spectroscopic techniques. The electronic changes and iron-ligand redox features of this LiFeSO4F-PEDOT composite are probed upon delithiation through X-ray absorption spectroscopy. The PEDOT coating, which is necessary here to obtain enough electrical conductivity for the electrochemical reactions of LiFeSO4F to occur, is electrochemically stable within the voltage window employed for cell cycling. Although the electronic configuration of PEDOT shows also some changes in correspondence of its reduced and oxidized forms after electrochemical conditioning in Li half-cells, its p-type doping is fully retained between 2.7 and 4.1 V with respect to Li+/Li during the first few cycles. An increased iron-ligand interaction is observed in LixFeSO4F during electrochemical lithium extraction, which appears to be a general trend for polyanionic insertion compounds. This finding is crucial for a deeper understanding of a series of oxidation phenomena in Li-ion battery cathode materials and helps paving the way to the exploration of new energy storage materials with improved electrochemical performances.

Item Type: Article
DOI/Identification number: 10.1016/j.jpowsour.2019.02.039
Uncontrolled keywords: Li-ion batteries, Lithium iron sulphate fluoride, Tavorite structureX-ray absorption spectroscopy, Conductive polymers, Anionic redox processes
Divisions: Faculties > Sciences > School of Physical Sciences
Depositing User: Maria Alfredsson
Date Deposited: 24 Apr 2019 11:15 UTC
Last Modified: 15 Feb 2020 00:00 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/73608 (The current URI for this page, for reference purposes)
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