First-principles study of the discharge electrochemical and catalytic performance of the sulfur cathode host Fe0.875M0.125S2 (M = Ti, V)

Lithium–sulfur batteries (LSBs) are one of the most promising energy storage devices with high energy density. However, their application and commercialization are hampered by the slow Li–S redox chemistry. Fe0.875M0.125S2 (M = Ti, V), as the sulfur cathode host, enhances the Li–S redox chemistry. F...

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Published in:Physical chemistry chemical physics : PCCP 2024-01, Vol.26 (3), p.2249-2259
Main Authors: Wei, Cheng-Dong, Xue, Hong-Tao, Hu, Yu-Xia, Zhao, Qing-Shan, Tang, Fu-Ling
Format: Article
Language:English
Subjects:
Cathodes
Chemical reduction
Commercialization
Decomposition reactions
Discharge
Electric potential
Electrical resistivity
Energy storage
First principles
Free energy
Heat of formation
Lithium sulfur batteries
Monte Carlo simulation
Oxidation
Pyrite
Sulfur
Titanium
Vanadium
Voltage
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Summary:Lithium–sulfur batteries (LSBs) are one of the most promising energy storage devices with high energy density. However, their application and commercialization are hampered by the slow Li–S redox chemistry. Fe0.875M0.125S2 (M = Ti, V), as the sulfur cathode host, enhances the Li–S redox chemistry. FeS2 with Pa3 is transformed into Li2FeS2 with P3m1 after discharge. The structure changes and physicochemical properties during Fe0.875M0.125S2 discharge process are further investigated to screen out the sulfur cathode host materials with the best comprehensive properties. The discharge structure of Fe0.875M0.125S2 is verified by the thermodynamic stability of Li-deficient phases, voltage and capacity based on Monte Carlo methods. Fe0.875M0.125S2 with Pa3 is transformed into Li2Fe0.875M0.125S2 with P3m1 after discharge. Using the first-principles calculations, the physicochemical properties of Li2Fe0.875M0.125S2 are systematically investigated, including the formation energy, voltage, theoretical capacity, electrical conductivity, Li+ diffusion, catalytic performance and Li2S oxidation decomposition. The average redox voltage of Li2Fe0.875V0.125S2 is higher than that of Li2Fe0.875Ti0.125S2. Li2Fe0.875M0.125S2 shows metallic properties. Li2Fe0.875V0.125S2 is more beneficial to the reduction reaction of Li2S2 and Li2S oxidation decomposition. Fe0.875V0.125S2 has more potential as the sulfur cathode host than Fe0.875Ti0.125S2 in LSBs. A new strategy for the selection of the sulfur cathode host material for LSBs is provided by this work.
ISSN:1463-9076
1463-9084
DOI:10.1039/d3cp04694j