The mechanism of Li[sub]2S activation in lithium-sulfur batteries

can we avoid the polysulfide formation?

Alen Vižintin (Author), Laurent Chabanne (Author), Elena Tchernychova (Author), Iztok Arčon (Author), Lorenzo Stievano (Author), Giuliana Aquilanti (Author), Markus Antonietti (Author), Tim-Patrick Fellinger (Author), Robert Dominko (Author)

Abstract

Electrochemical reactions in the LieS batteries are considered as a multistep reaction process with at least 2e3 equilibrium states. Here we report a possibility of having a conversion of Li2S into sulfur without detectible formation of polysulfides. That was confirmed by using a novel material system consisting of carbon coated Li2S particles prepared by carbothermal reduction of Li2SO4. Two independent in operando measurements showed direct oxidation of Li2S into sulfur for this system, with almost negligible formation of polysulfides at potentials above 2.5 V vs. Li/Liþ. Our results link the diversity of first charge profiles in the literature to the Li2S oxidation mechanism and show the importance of ionic wiring within the material. Furthermore, we demonstrate that the Li2S oxidation mechanism depends on the relative amount of soluble sulfur in the electrolyte. By controlling the type and the amount of electrolyte within the encapsulating carbon shell, it is thereby possible to control the reaction mechanism of Li2S activation.

Keywords

Lithium-sulfur batteries;Li2S active material;XAS;UV/Vis spectroscopy;activation;

Data

Language:	English
Year of publishing:	2017
Typology:	1.01 - Original Scientific Article
Organization:	UNG - University of Nova Gorica
UDC:	544.5/.6
COBISS:	4706555
ISSN:	0378-7753
Views:	4374
Downloads:	0
Average score:	0 (0 votes)
Metadata:

Other data

URN:	URN:SI:UNG
Type (COBISS):	Not categorized
Pages:	str. 208-217
Issue:	Vol. 344
Chronology:	2017
DOI:	10.1016/j.jpowsour.2017.01.112
ID:	9585660