TY - JOUR
T1 - Nitride MXenes as sulfur hosts for thermodynamic and kinetic suppression of polysulfide shuttling
T2 - A computational study
AU - Fan, Ke
AU - Ying, Yiran
AU - Luo, Xin
AU - Huang, Haitao
N1 - Funding Information:
This work was supported by the Research Grants Council of the Hong Kong Special Administrative Region, China (Project No. PolyU152178/20E), the Hong Kong Polytechnic University (Project No. RHA3), and Science and Technology Program of Guangdong Province of China (Project No. 2019A050510012 and 2020A0505090001). X. L. acknowledges support from NSFC (No. 11804286, No. 12172386), the National Natural Science Foundation of Guangdong Province, China (Grant No. 2021B1515020021), and the Fundamental Research Funds for the Central Universities, Sun Yat-sen University (Grant No. 2021qntd27).
Publisher Copyright:
© The Royal Society of Chemistry.
PY - 2021/12/7
Y1 - 2021/12/7
N2 - The practical applications of lithium-sulfur (Li-S) batteries are greatly hindered by the poor conductivity of sulfur, the shuttling of lithium polysulfides (LiPSs), and the sluggish kinetics in the charge-discharge process. In order to solve these problems, here we propose the surface-functionalized V2N MXenes as the host materials to improve the electrochemical performance of Li-S batteries. Based on the density functional theory (DFT) calculations, we found that both the bare and functionalized V2NT2 (T = O, F, OH, and S) exhibit metallicity, and three of them (V2NO2, V2NF2, and V2NS2) possess moderate LiPS adsorption strength, which thermodynamically benefits the suppression of the dissolution and shuttling of LiPSs. Besides, V2NS2 shows the lowest Gibbs free energy barrier for the sulfur reduction reaction (0.49 eV) during discharge, which kinetically suppresses the dissolution and shuttling of LiPSs by expediting the decomposition process from soluble LiPSs to insoluble ones. Moreover, surface functionalized V2NT2 also exhibits outstanding catalytic ability for Li2S decomposition during charge, which decreases the energy barrier from 3.64 eV (bare V2N) to 1.55 (V2NO2) and 1.19 eV (V2NS2), and increases the charging kinetics. Based on these results, V2NS2 monolayers are suggested as promising host materials for S cathodes due to the fast charge/discharge kinetics and effective suppression of LiPS shuttling. This theoretical study provides further insight into the application of nitride MXenes and other two-dimensional materials as conductive anchoring materials for Li-S batteries.
AB - The practical applications of lithium-sulfur (Li-S) batteries are greatly hindered by the poor conductivity of sulfur, the shuttling of lithium polysulfides (LiPSs), and the sluggish kinetics in the charge-discharge process. In order to solve these problems, here we propose the surface-functionalized V2N MXenes as the host materials to improve the electrochemical performance of Li-S batteries. Based on the density functional theory (DFT) calculations, we found that both the bare and functionalized V2NT2 (T = O, F, OH, and S) exhibit metallicity, and three of them (V2NO2, V2NF2, and V2NS2) possess moderate LiPS adsorption strength, which thermodynamically benefits the suppression of the dissolution and shuttling of LiPSs. Besides, V2NS2 shows the lowest Gibbs free energy barrier for the sulfur reduction reaction (0.49 eV) during discharge, which kinetically suppresses the dissolution and shuttling of LiPSs by expediting the decomposition process from soluble LiPSs to insoluble ones. Moreover, surface functionalized V2NT2 also exhibits outstanding catalytic ability for Li2S decomposition during charge, which decreases the energy barrier from 3.64 eV (bare V2N) to 1.55 (V2NO2) and 1.19 eV (V2NS2), and increases the charging kinetics. Based on these results, V2NS2 monolayers are suggested as promising host materials for S cathodes due to the fast charge/discharge kinetics and effective suppression of LiPS shuttling. This theoretical study provides further insight into the application of nitride MXenes and other two-dimensional materials as conductive anchoring materials for Li-S batteries.
UR - http://www.scopus.com/inward/record.url?scp=85119259662&partnerID=8YFLogxK
U2 - 10.1039/d1ta06759a
DO - 10.1039/d1ta06759a
M3 - Journal article
AN - SCOPUS:85119259662
SN - 2050-7488
VL - 9
SP - 25391
EP - 25398
JO - Journal of Materials Chemistry A
JF - Journal of Materials Chemistry A
IS - 45
ER -