MoS2/Mayenite Electride Hybrid as a Cathode Host for Suppressing Polysulfide Shuttling and Promoting Kinetics in Lithium–Sulfur Batteries

Author(s)
Thatsami, Niphat
Tangpakonsab, Parinya
Sikam, Pornsawan
Hussain, Tanveer
Tamwattana, Orapa
Watcharapasorn, Anucha
Moontragoon, Pairot
Pathak, Biswarup
Kaewmaraya, Thanayut
Publication Date
2024-07-24
Abstract
<p>The commercial viability of emerging lithium−sulfur batteries (LSBs) remains greatly hindered by short lifespans caused by electrically insulating sulfur, lithium polysulfides (Li<sub>2</sub>S<sub><i>n</i></sub>; 1 ≤ n ≤ 8) shuttling, and sluggish sulfur reduction reactions(SRRs). This work proposes the utilization of a hybrid composed of sulfiphilic MoS<sub>2</sub> and mayenite electride (C12A7:e<sup>−</sup>) as a cathode host to address these challenges. Specifically, abundant cement-based C12A7:e<sup>−</sup> is the most stable inorganic electrode, possessing the ultimate electrical conductivity and low work function. Through density functional theory simulations, the key aspects of the MoS<sub>2</sub>/C12A7:e<sup>−</sup> hybrid including electronic properties, interfacial binding with Li<sub>2</sub>S<sub><i>n</i></sub>, Li+ diffusion, and SRR have been unraveled. Our findings reveal the rational rules for MoS<sub>2</sub> as an efficient cathode host by enhancing its mutual electrical conductivity and surface polarity <i>via</i> MoS<sub>2</sub>/C12A7:e<sup>−</sup>. The improved electrical conductivity of MoS<sub>2</sub> is attributed to the electron donation from C12A7:e<sup>−</sup> to MoS<sub>2</sub>, yielding a semiconductor-to-metal transition. The resultant band positions of MoS<sub>2</sub>/C12A7:e<sup>−</sup> are well matched with those of conventional current-collecting materials (<i>i.e.</i>, Cu and Ni), electrochemically enhancing the electronic transport. Theaccepted charge also intensifies MoS<sub>2</sub> surface polarity for attracting polar Li<sub>2</sub>S<sub><i>n</i></sub> by forming stronger bonds with Li<sub>2</sub>S<sub><i>n</i></sub> <i>via</i> ionic Li−Sbonds than electrolytes with Li<sub>2</sub>S<sub><i>n</i></sub>, thereby preventing polysulfide shuttling. Importantly, MoS<sub>2</sub>/C12A7:e<sup>−</sup> not only promotes rapid reaction kinetics by reducing ionic diffusion barriers but also lowers the Gibbs free energies of the SRR for effective S<sub>8</sub>-to-Li<sub>2</sub>Sconversion. Beyond the reported applications of C12A7:e<sup>−</sup>, this work highlights its functionality as an electrode material to boost the efficiency of LSBs.</p>
Citation
ACS Applied Materials and Interfaces, 16(29), p. 37994-38005
Link
Publisher
American Chemical Society
Rights
Attribution-NonCommercial-NoDerivatives 4.0 International
Title
MoS2/Mayenite Electride Hybrid as a Cathode Host for Suppressing Polysulfide Shuttling and Promoting Kinetics in Lithium–Sulfur Batteries
Type of document
Journal Article
Entity Type
Publication

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