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

Cheng-Dong Wei; Hong-Tao Xue; Yu-Xia Hu; Qing-Shan Zhao; Fu-Ling Tang

doi:10.1039/d3cp04694j

First-principles study of the discharge electrochemical and catalytic performance of the sulfur cathode host Fe_0.875M_0.125S₂ (M = Ti, V)

Phys Chem Chem Phys. 2024 Jan 17;26(3):2249-2259. doi: 10.1039/d3cp04694j.

Authors

Cheng-Dong Wei^{1

2}, Hong-Tao Xue^{1

2}, Yu-Xia Hu^{1

2}, Qing-Shan Zhao^{1

2}, Fu-Ling Tang^{1

2}

Affiliations

¹ School of Materials Science and Engineering, Lanzhou University of Technology, Lanzhou 730050, China. tfl@lut.edu.cn.
² State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals, Lanzhou University of Technology, Lanzhou 730050, China.

PMID: 38165279
DOI: 10.1039/d3cp04694j

Abstract

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. Fe_0.875M_0.125S₂ (M = Ti, V), as the sulfur cathode host, enhances the Li-S redox chemistry. FeS₂ with Pa3̄ is transformed into Li₂FeS₂ with P3̄m1 after discharge. The structure changes and physicochemical properties during Fe_0.875M_0.125S₂ discharge process are further investigated to screen out the sulfur cathode host materials with the best comprehensive properties. The discharge structure of Fe_0.875M_0.125S₂ is verified by the thermodynamic stability of Li-deficient phases, voltage and capacity based on Monte Carlo methods. Fe_0.875M_0.125S₂ with Pa3̄ is transformed into Li₂Fe_0.875M_0.125S₂ with P3̄m1 after discharge. Using the first-principles calculations, the physicochemical properties of Li₂Fe_0.875M_0.125S₂ 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 Li₂Fe_0.875V_0.125S₂ is higher than that of Li₂Fe_0.875Ti_0.125S₂. Li₂Fe_0.875M_0.125S₂ shows metallic properties. Li₂Fe_0.875V_0.125S₂ is more beneficial to the reduction reaction of Li₂S₂ and Li₂S oxidation decomposition. Fe_0.875V_0.125S₂ has more potential as the sulfur cathode host than Fe_0.875Ti_0.125S₂ in LSBs. A new strategy for the selection of the sulfur cathode host material for LSBs is provided by this work.