{"title":"S-doped mesoporous graphene modified separator for high performance lithium-sulfur batteries","authors":"","doi":"10.1016/j.matre.2024.100279","DOIUrl":null,"url":null,"abstract":"<div><p>Due to their low cost, environmental friendliness and high energy density, the lithium-sulfur batteries (LSB) have been regarded as a promising alternative for the next generation of rechargeable battery systems. However, the practical application of LSB is seriously hampered by its short cycle life and high self-charge owing to the apparent shuttle effect of soluble lithium polysulfides. Using MgSO<sub>4</sub>@MgO composite as both template and dopant, template-guided S-doped mesoporous graphene (SMG) is prepared via the fluidized-bed chemical vapor deposition method. As the polypropylene (PP) modifier, SMG with high specific surface area, abundant mesoporous structures and moderate S doping content offers a wealth of physical and chemical adsorptive sites and reduced interfacial contact resistance, thereby restraining the serious shuttle effects of lithium polysulfides. Consequently, the LSB configured with mesoporous graphene (MG) as S host material and SMG as a separator modifier exhibits an enhanced electrochemical performance with a high average capacity of 955.64 mA h g<sup>−1</sup> at 1C and a small capacity decay rate of 0.109% per cycle. Additionally, the density functional theory (DFT) calculation models have been rationally constructed and demonstrated that the doped S atoms in SMG possess higher binding energy to lithium polysulfides than that in MG, indicating that the SMG/PP separator can effectively capture soluble lithium polysulfides via chemical binding forces. This work would provide valuable insight into developing a versatile carbon-based separator modifier for LSB.</p></div>","PeriodicalId":61638,"journal":{"name":"材料导报:能源(英文)","volume":null,"pages":null},"PeriodicalIF":0.0000,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666935824000491/pdfft?md5=ef2920c58bd0482bc23243ecb92475fc&pid=1-s2.0-S2666935824000491-main.pdf","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"材料导报:能源(英文)","FirstCategoryId":"1087","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S2666935824000491","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
Abstract
Due to their low cost, environmental friendliness and high energy density, the lithium-sulfur batteries (LSB) have been regarded as a promising alternative for the next generation of rechargeable battery systems. However, the practical application of LSB is seriously hampered by its short cycle life and high self-charge owing to the apparent shuttle effect of soluble lithium polysulfides. Using MgSO4@MgO composite as both template and dopant, template-guided S-doped mesoporous graphene (SMG) is prepared via the fluidized-bed chemical vapor deposition method. As the polypropylene (PP) modifier, SMG with high specific surface area, abundant mesoporous structures and moderate S doping content offers a wealth of physical and chemical adsorptive sites and reduced interfacial contact resistance, thereby restraining the serious shuttle effects of lithium polysulfides. Consequently, the LSB configured with mesoporous graphene (MG) as S host material and SMG as a separator modifier exhibits an enhanced electrochemical performance with a high average capacity of 955.64 mA h g−1 at 1C and a small capacity decay rate of 0.109% per cycle. Additionally, the density functional theory (DFT) calculation models have been rationally constructed and demonstrated that the doped S atoms in SMG possess higher binding energy to lithium polysulfides than that in MG, indicating that the SMG/PP separator can effectively capture soluble lithium polysulfides via chemical binding forces. This work would provide valuable insight into developing a versatile carbon-based separator modifier for LSB.
锂硫电池(LSB)具有成本低、环保和能量密度高等优点,被视为下一代充电电池系统的理想替代品。然而,由于可溶性锂多硫化物的明显穿梭效应,锂硫电池的循环寿命短和高自充电率严重阻碍了其实际应用。利用 MgSO4@MgO 复合材料作为模板和掺杂剂,通过流化床化学气相沉积法制备了模板引导的 S 掺杂介孔石墨烯(SMG)。作为聚丙烯(PP)的改性剂,SMG 具有高比表面积、丰富的介孔结构和适度的 S 掺杂含量,可提供丰富的物理和化学吸附位点并降低界面接触电阻,从而抑制多硫化锂的严重穿梭效应。因此,以介孔石墨烯(MG)为 S 主材料、SMG 为分离改性剂的 LSB 具有更高的电化学性能,在 1C 时的平均容量高达 955.64 mA h g-1,且每周期的容量衰减率仅为 0.109%。此外,合理构建的密度泛函理论(DFT)计算模型表明,SMG 中掺杂的 S 原子与多硫化锂的结合能高于 MG,表明 SMG/PP 分离剂可通过化学结合力有效捕获可溶性多硫化锂。这项工作将为开发用于 LSB 的多功能碳基分离改性剂提供宝贵的见解。