Sun Jinhua, Hwang Jang-Yeon, Jankowski Piotr, Xiao Linhong, Sanchez Jaime S, Xia Zhenyuan, Lee Suyeong, Talyzin Alexandr V, Matic Aleksandar, Palermo Vincenzo, Sun Yang-Kook, Agostini Marco
Department of Industrial and Materials Science, Chalmers University of Technology, Göteborg, 41296, Sweden.
Department of Materials Science and Engineering, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwangju, 61186, South Korea.
Small. 2021 Apr;17(17):e2007242. doi: 10.1002/smll.202007242. Epub 2021 Mar 14.
Lithium-sulfur (Li-S) batteries are considered one of the most promising energy storage technologies, possibly replacing the state-of-the-art lithium-ion (Li-ion) batteries owing to their high energy density, low cost, and eco-compatibility. However, the migration of high-order lithium polysulfides (LiPs) to the lithium surface and the sluggish electrochemical kinetics pose challenges to their commercialization. The interactions between the cathode and LiPs can be enhanced by the doping of the carbon host with heteroatoms, however with relatively low doping content (<10%) in the bulk of the carbon, which can hardly interact with LiPs at the host surface. In this study, the grafting of versatile functional groups with designable properties (e.g., catalytic effects) directly on the surface of the carbon host is proposed to enhance interactions with LiPs. As model systems, benzene groups containing N/O and S/O atoms are vertically grafted and uniformly distributed on the surface of expanded reduced graphene oxide, fostering a stable interface between the cathode and LiPs. The combination of experiments and density functional theory calculations demonstrate improvements in chemical interactions between graphene and LiPs, with an enhancement in the electrochemical kinetics, power, and energy densities.
锂硫（Li-S）电池被认为是最具前景的储能技术之一，因其高能量密度、低成本和生态兼容性，有可能取代现有的锂离子（Li-ion）电池。然而，高阶多硫化锂（LiPs）向锂表面的迁移以及缓慢的电化学动力学对其商业化构成了挑战。通过用杂原子掺杂碳主体可以增强阴极与LiPs之间的相互作用，然而在碳主体中掺杂含量相对较低（<10%），这几乎无法与主体表面的LiPs相互作用。在本研究中，提出直接在碳主体表面接枝具有可设计性质（如催化作用）的多功能官能团，以增强与LiPs的相互作用。作为模型系统，含有N/O和S/O原子的苯基团垂直接枝并均匀分布在膨胀还原氧化石墨烯表面，促进了阴极与LiPs之间的稳定界面。实验和密度泛函理论计算相结合，证明了石墨烯与LiPs之间化学相互作用的改善，同时提高了电化学动力学、功率和能量密度。
