Two-Dimensional Li_xMoS₂/Graphene Heterostructures for Li–S Batteries

<b>Abstract</b><br/>Lithium-sulfur (Li-S) batteries based on redox chemistry can store more energy than conventional insertion-type lithium-ion technologies^1,2. Our previous discoveries have shown that compact electrodes assembled from monolayered nanosheets of lithiated metallic 1T phase molybdenum disulfide (Li_xMoS₂) are electrically and ionically conductive, lyophilic and catalytically active^3-6. In this presentation, I will describe a sulfur host design of two-dimensional (2D) Li_xMoS₂/graphene heterostructure for Li-S batteries. The construction of heterointerfaces results in charge transfer from graphene to Li_xMoS₂, which yields enhanced catalytic activity and promotes redox kinetics for sulfur conversion. The accumulation of greater charge in the Li_xMoS₂ layer of heterostructures also reduces its Lewis acidity compared to that of bare Li_xMoS₂. The resultant ampere-hour-scale Li-S pouch cells deliver energy density of exceeding 400 Wh kg^-1. This work demonstrates an universal strategy of using 2D heterostructures to tune the electrode properties for realising practical energy storage.<br/><br/><b>Reference</b><br/>1. Choi, J. W. & Aurbach, D. Promise and reality of post-lithium-ion batteries with high energy densities. <i>Nat. Rev. Mater.</i> <b>1</b>, 16013 (2016).<br/>2. Zhou, G., Chen, H. & Cui, Y. Formulating energy density for designing practical lithium–sulfur batteries. <i>Nat. Energy</i> <b>7</b>, 312–319 (2022).<br/>3. Li, Z., Sami, I., Yang, J., Li, J., Kumar, R. V. & Chhowalla, M. Lithiated metallic molybdenum disulfide nanosheets for high performance lithium-sulfur batteries.<i> Nat. Energy</i> <b>8</b>, 84–93 (2023)<br/>4. Eda, G. <i>et al.</i> Photoluminescence from chemically exfoliated MoS₂. <i>Nano Lett.</i> <b>11</b>, 5111–5116 (2011).<br/>5. Chhowalla, M. <i>et al.</i> The chemistry of two-dimensional layered transition metal dichalcogenide nanosheets. <i>Nat. Chem.</i> <b>5</b>, 263–275 (2013).<br/>6. Voiry, D. <i>et al.</i> The role of electronic coupling between substrate and 2D MoS₂ nanosheets in electrocatalytic production of hydrogen. <i>Nat. Mater.</i> <b>15</b>, 1003–1009 (2016).