Tang Hu, You Lei, Liu Jianwen, Wang Shiquan, Wang Pengyu, Feng Chuanqi, Guo Zaiping
Hubei Collaborative Innovation Center for Advanced Organic Chemical Materials & Ministry of Educational Key Laboratory for the Synthesis and Application of Organic Functional Molecules & College of Chemistry and Chemical Engineering , Hubei University , Wuhan 430062 , P. R. China.
Institute for Superconducting and Electronic Materials, Australian Institute for Innovative Materials , University of Wollongong , Innovation Campus , North Wollongong , New South Wales 2522 , Australia.
ACS Appl Mater Interfaces. 2019 May 22;11(20):18448-18455. doi: 10.1021/acsami.9b04167. Epub 2019 May 8.
Although lithium-sulfur batteries have been regarded as the most promising candidates for next-generation energy storage devices with high specific capacity, their rapid capacity decay, mainly caused by volume expansion and dissolution of polysulfides, has limited their practical applications. Aiming at these issues, herein, we have designed an ideal three-dimensional (3D)-structured polypyrrole@sulfur@graphene aerogel (PPy@S@GA) as an efficient sulfur host via advanced pyrrole vapor polymerization. GA with an interconnected 3D porous structure provides an excellent conductive network for electrons and a channel for ion transfer, as well as a physical barrier or absorber for the polysulfides. In addition, physical confinement and chemical adsorption are further strengthened by the PPy coating layer with polar nitrogen. The electrode with the PPy@S@GA 3D structure delivered a superior initial discharge specific capacity of 1135 mA h g and a capacity of 741 mA h g after 500 cycles at a rate of 0.5 C, with capacity fading as low as 0.031% per cycle, superior to both a sulfur electrode and a S@GA electrode. These results demonstrate that GA as a sulfur host further coated with PPy is a promising cathode for pursuing high-performance Li-S batteries.
尽管锂硫电池被认为是具有高比容量的下一代储能设备最有前景的候选者，但其快速的容量衰减（主要由多硫化物的体积膨胀和溶解引起）限制了它们的实际应用。针对这些问题，在此，我们通过先进的吡咯气相聚合设计了一种理想的三维（3D）结构聚吡咯@硫@石墨烯气凝胶（PPy@S@GA）作为高效的硫宿主。具有相互连接的3D多孔结构的GA为电子提供了优异的导电网络和离子传输通道，同时也是多硫化物的物理屏障或吸收体。此外，带有极性氮的PPy涂层进一步加强了物理限制和化学吸附。具有PPy@S@GA 3D结构的电极在0.5 C的电流密度下首次放电比容量高达1135 mA h g，500次循环后容量为741 mA h g，容量衰减率低至每循环0.031%，优于硫电极和S@GA电极。这些结果表明，用PPy进一步包覆的GA作为硫宿主是一种有前途的用于高性能锂硫电池的正极材料。
