Tethered Molecular Sorbents: Enabling Metal‐Sulfur Battery Cathodes |
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Authors: | Lin Ma Houlong Zhuang Yingying Lu Surya S Moganty Richard G Hennig Lynden A Archer |
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Institution: | 1. Department of Materials Science and Engineering, Cornell University, Ithaca, NY, USA;2. School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, NY, USA;3. NOHMs Technologies, Inc., Rochester, NY |
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Abstract: | A rechargeable battery that uses sulfur at the cathode and a metal (e.g., Li, Na, Mg, or Al) at the anode provides perhaps the most promising path to a solid‐state, rechargeable electrochemical storage device capable of high charge storage capacity. It is understood that solubilization in the electrolyte and loss of sulfur in the form of long‐chain lithium polysulfides (Li2Sx, 2 < x < 8) has hindered development of the most studied of these devices, the rechargeable Li‐S battery. Beginning with density‐functional calculations of the structure and interactions of a generic lithium polysulfide species with nitrile containing molecules, it is shown that it is possible to design nitrile‐rich molecular sorbents that anchor to other components in a sulfur cathode and which exert high‐enough binding affinity to Li2Sx to limit its loss to the electrolyte. It is found that sorbents based on amines and imidazolium chloride present barriers to dissolution of long‐chain Li2Sx and that introduction of as little as 2 wt% of these molecules to a physical sulfur‐carbon blend leads to Li‐S battery cathodes that exhibit stable long‐term cycling behaviors at high and low charge/discharge rates. |
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Keywords: | lithium‐sulfur batteries molecular sorbents lithium‐nitrile interactions sequestering lithium polysulfide |
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