High‐Performance Lithium‐Sulfur Batteries with a Self‐Supported, 3D Li2S‐Doped Graphene Aerogel Cathodes |
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Authors: | Guangmin Zhou Eunsu Paek Gyeong S Hwang Arumugam Manthiram |
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Institution: | 1. Materials Science and Engineering Program & Texas Materials Institute, The University of Texas at Austin, Austin, TX, USA;2. McKetta Department of Chemical Engineering, University of Texas at Austin, Austin, TX, USA |
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Abstract: | Lithium‐sulfur (Li‐S) batteries are being considered as the next‐generation high‐energy‐storage system due to their high theoretical energy density. However, the use of a lithium‐metal anode poses serious safety concerns due to lithium dendrite formation, which causes short‐circuiting, and possible explosions of the cell. One feasible way to address this issue is to pair a fully lithiated lithium sulfide (Li2S) cathode with lithium metal‐free anodes. However, bulk Li2S particles face the challenges of having a large activation barrier during the initial charge, low active‐material utilization, poor electrical conductivity, and fast capacity fade, preventing their practical utility. Here, the development of a self‐supported, high capacity, long‐life cathode material is presented for Li‐S batteries by coating Li2S onto doped graphene aerogels via a simple liquid infiltration–evaporation coating method. The resultant cathodes are able to lower the initial charge voltage barrier and attain a high specific capacity, good rate capability, and excellent cycling stability. The improved performance can be attributed to the (i) cross‐linked, porous graphene network enabling fast electron/ion transfer, (ii) coated Li2S on graphene with high utilization and a reduced energy barrier, and (iii) doped heteroatoms with a strong binding affinity toward Li2S/lithium polysulfides with reduced polysulfide dissolution based on first‐principles calculations. |
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Keywords: | Li‐S batteries lithium sulfide nitrogen/boron doping graphene aerogel cathodes self‐supported electrode |
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