New progress in lithium-sulfur battery research

　　Recently, the internationally renowned academic journal ACS Nano, with the title of "New System of Mesoporous Graphene Dispersed Heterojunction Tin-Based Lithium-Sulfur Battery Separator Coating", reported online the research team of functional carbon materials from the School of Chemical Engineering of East China University of Science and Technology in the field of lithium-sulfur batteries.
New developments in research
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　　Lithium-sulfur batteries are considered to be one of the most promising electrochemical energy storage systems after lithium-ion batteries due to their low cost, ultra-high theoretical capacity, and high energy density
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For the sulfur cathode, lithium polysulfide can be dissolved in the electrolyte to form a "shuttle effect", which leads to problems such as low utilization rate of active material sulfur and rapid capacity decay; for the lithium anode, the uncontrollable growth of lithium dendrites can easily cause the battery Short circuits are even a safety hazard
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Therefore, how to simultaneously suppress the "shuttle effect" and "dendritic growth" during long-term battery cycling has become a daunting technical challenge in the practical application of lithium-sulfur batteries
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　　In response to the above problems, the functional carbon materials research team synthesized a "dual-functional" graphene mesoporous SnO 2 /SnSe 2 nanosheet as a separator modification layer (G-mSnO 2 /SnSe 2 ) for lithium-sulfur batteries , which has high Characteristics such as electrical conductivity, strong chemisorption sites (SnO ₂ ) and dynamic intercalation transition kinetics (LixSnSe ₂ ) .
The researchers used in-situ XRD, in-situ Raman, ex-situ XANES and DFT simulation calculations to confirm that the separator modification layer has a good inhibitory effect on the "shuttle effect" and can promote the catalytic conversion of lithium polysulfides .

　　In addition, the strong lithiophilic sites and porous structure of G-mSnO₂/SnSe ₂ help to reduce the nucleation overpotential of Li and the uniform nucleation of the anode surface during Li exfoliation and deposition, thereby effectively inhibiting the growth of Li dendrites
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When G-mSnO ₂ /SnSe ₂ is used as a separator modification layer for Li-S batteries, it exhibits excellent electrochemical performance: high sulfur utilization, long cycle life, and rate capability; Li|Li symmetric battery at 1 mA cm⁻² /1 mAh cm ⁻ ² can be stably cycled for more than 2200 h, and the coulombic efficiency of Li-Cu battery remains above 99% after 500 cycles
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Furthermore, the assembled 1.
6 g S/Ah pouch battery still achieves a high energy density of 359 Wh/kg under the condition of low electrolyte/sulfur ratio and low anode/cathode ratio
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　　Professor Zhan Liang from the School of Chemical Engineering of East China University of Science and Technology and Professor Chen Renjie of Beijing Institute of Technology are the corresponding authors of the paper.
The research work has been funded by the National Natural Science Foundation of China and other projects
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