3D双限域硫封装在多孔碳纳米片中并被石墨烯气凝胶包裹,用作先进锂硫电池的阴极。

3D dual-confined sulfur encapsulated in porous carbon nanosheets and wrapped with graphene aerogels as a cathode for advanced lithium sulfur batteries.

作者信息

Hou Yang, Li Jianyang, Gao Xianfeng, Wen Zhenhai, Yuan Chris, Chen Junhong

机构信息

Department of Mechanical Engineering, University of Wisconsin-Milwaukee, 3200 North Cramer Street, Milwaukee, Wisconsin 53211, USA.

出版信息

Nanoscale. 2016 Apr 21;8(15):8228-35. doi: 10.1039/c5nr09037g.

Abstract

Although lithium-sulfur (Li-S) batteries have attracted much attention due to their high theoretical specific energy and low cost, their practical applications have been severely hindered by poor cycle life, inadequate sulfur utilization, and the insulating nature of sulfur. Here, we report a rationally designed Li-S cathode with a dual-confined configuration formed by confining sulfur in 2D carbon nanosheets with an abundant porous structure followed by 3D graphene aerogel wrapping. The porous carbon nanosheets act as the sulfur host and suppress the diffusion of polysulfide, while the graphene conductive networks anchor the sulfur-adsorbed carbon nanosheets, providing pathways for rapid electron/ion transport and preventing polysulfide dissolution. As a result, the hybrid electrode exhibits superior electrochemical performance, including a large reversible capacity of 1328 mA h g(-1) in the first cycle, excellent cycling stability (maintaining a reversible capacity of 647 mA h g(-1) at 0.2 C after 300 cycles) with nearly 100% Coulombic efficiency, and a high rate capability of 512 mA h g(-1) at 8 C for 30 cycles, which is among the best reported rate capabilities.

摘要

尽管锂硫(Li-S)电池因其高理论比能量和低成本而备受关注,但其实际应用却因循环寿命短、硫利用率不足以及硫的绝缘性质而受到严重阻碍。在此,我们报道了一种合理设计的锂硫正极,其具有双限制结构,通过将硫限制在具有丰富多孔结构的二维碳纳米片中,然后用三维石墨烯气凝胶包裹形成。多孔碳纳米片作为硫的主体,抑制多硫化物的扩散,而石墨烯导电网络锚定吸附硫的碳纳米片,为快速电子/离子传输提供途径并防止多硫化物溶解。结果,该复合电极表现出优异的电化学性能,包括首次循环中高达1328 mA h g⁻¹的可逆容量、出色的循环稳定性(300次循环后在0.2 C下保持647 mA h g⁻¹的可逆容量)且库仑效率接近100%,以及在8 C下30次循环时512 mA h g⁻¹的高倍率性能,这是已报道的最佳倍率性能之一。

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