Multifunctional Effects of Sulfonyl-Anchored, Dual-Doped Multilayered Graphene for High Areal Capacity Lithium Sulfur Batteries.,ACS Central Science

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Multifunctional Effects of Sulfonyl-Anchored, Dual-Doped Multilayered Graphene for High Areal Capacity Lithium Sulfur Batteries.
ACS Central Science ( IF 12.7 ) Pub Date : 2019-12-05 , DOI: 10.1021/acscentsci.9b01005
Masud Rana ₁ , Qiu He ₂ , Bin Luo ₁ , Tongen Lin ₁ , Lingbing Ran ₁ , Ming Li ₁ , Ian Gentle ₁ , Ruth Knibbe ₁

Affiliation

Li-S batteries (LSBs) require a minimum 6 mAh cm-2 areal capacity to compete with the state-of-the-art lithium ion batteries (LIBs). However, this areal capacity is difficult to achieve due to a major technical issue-the shuttle effect. Nonpolar carbon materials limit the shuttle effect through physical confinement. However, the polar polysulfides (PSs) only provide weak intermolecular interactions (0.1-0.7 eV) with these nonpolar carbon materials. The physically encapsulated PSs inside the nonpolar carbon scaffold eventually diffuses out and starts shuttling. Chemically interactive hosts are more effective at interacting with the PSs due to high binding energies. Herein, a multifunctional separator coating of nitrogen-doped multilayer graphene (NGN) and -SO3 - containing Nafion (N-NGN) is used to mitigate PS shuttling and to produce a high areal capacity LSB. The Nafion is used as a binder instead of PVDF to provide an additional advantage of -SO3 - to chemically bind the PS. The motive of this research is to investigate the effect of highly electronegative N and -SO3 - (N-NGN) in comparison with the -OH, -COOH, and -SO3 - groups from a hydroxyl graphene and Nafion composite (N-OHGN) to mitigate PS shuttling in LSBs. The highly conductive doped graphene architecture (N-NGN) provides efficient pathways for both electrons and ions, which accelerates the electrochemical conversion at high sulfur loading. Moreover, the electron-rich pyridine N and -SO3 - show strong chemical affinity with the PS through polar-polar interactions, which is proven by the superior electrochemical performance and density functional theory calculations. Further, the N-NGN (5 h) produces a maximum areal capacity of 12.0 and 11.0 mAh cm-2, respectively, at 15 and 12 mg cm-2 sulfur loading. This areal capacity limit is significantly higher than the required areal capacity of LSBs for commercial application, which shows the significant strength of N-NGN as an excellent separator coating for LSBs.

中文翻译：

磺酰基固定的双掺杂多层石墨烯对高容量锂硫电池的多功能作用。

Li-S电池（LSB）至少需要6 mAh cm-2的面容量才能与最新的锂离子电池（LIB）竞争。然而，由于主要的技术问题-穿梭效应，难以实现这种区域容量。非极性碳材料通过物理限制来限制穿梭效应。但是，极性多硫化物（PSs）仅提供与这些非极性碳材料的弱分子间相互作用（0.1-0.7 eV）。最终，非极性碳支架内部的物理封装PS扩散并开始穿梭。由于高结合能，化学相互作用的主体在与PS相互作用方面更有效。在此处，掺氮的多层石墨烯（NGN）和含-SO3的Nafion（N-NGN）的多功能隔离涂层用于减轻PS穿梭并产生较高的面容量LSB。Nafion代替PVDF用作粘合剂，以提供-SO3的其他优点-化学键合PS。这项研究的目的是研究高电负性N和-SO3--（N-NGN）与羟基石墨烯和Nafion复合材料（N-OHGN）中的-OH，-COOH和-SO3-基团的影响减轻LSB中的PS穿梭。高导电性掺杂石墨烯结构（N-NGN）为电子和离子提供了有效的途径，从而在高硫负载下加速了电化学转化。而且，富电子吡啶N和-SO3-通过极性相互作用显示出与PS的强化学亲和力，这已通过出色的电化学性能和密度泛函理论计算得到证明。此外，在硫负荷为15和12 mg cm-2的情况下，N-NGN（5小时）产生的最大面积容量分别为12.0和11.0 mAh cm-2。该面容量极限显着高于商业应用中LSB所需的面容量，这表明N-NGN作为LSB的出色隔离涂层具有显着的强度。

更新日期：2019-12-27

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