Ye Chao, Jiao Yan, Chao Dongliang, Ling Tao, Shan Jieqiong, Zhang Binwei, Gu Qinfen, Davey Kenneth, Wang Haihui, Qiao Shi-Zhang
School of Chemical Engineering and Advanced Materials, The University of Adelaide, Adelaide, SA, 5005, Australia.
School of Materials Science and Engineering, Tianjin University, Tianjin, 300072, China.
Adv Mater. 2020 Mar;32(12):e1907557. doi: 10.1002/adma.201907557. Epub 2020 Feb 14.
Confinement of polysulfides in sulfur cathodes is pivotal for eliminating the "shuttle effect" in metal-sulfur batteries, which represent promising solutions for large-scale and sustainable energy storage. However, mechanistic exploration and in-depth understanding for the confinement of polysulfides remain limited. Consequently, it is a critical challenge to achieve highly stable metal-sulfur batteries. Here, based on a 2D metal-organic framework (2D MOF), a new mechanism to realize effective confinement of polysulfides is proposed. A combination of in situ synchrotron X-ray diffraction, electrochemical measurements, and theoretical computations reveal that the dynamic electron states of the Ni centers in the 2D MOF enable the interaction between polysulfides and the MOF in the discharge/charge process to be tuned, resulting in both strong adsorption and fast conversion kinetics of polysulfides. The resultant room-temperature sodium-sulfur batteries are amongst the most stable reported so far, thus demonstrating that the new mechanism opens a promising avenue for the development of high-performance metal-sulfur batteries.
将多硫化物限制在硫阴极中对于消除金属硫电池中的“穿梭效应”至关重要，金属硫电池是大规模可持续储能的有前景的解决方案。然而，对于多硫化物限制的机理探索和深入理解仍然有限。因此，实现高度稳定的金属硫电池是一项关键挑战。在此，基于二维金属有机框架（2D MOF），提出了一种实现多硫化物有效限制的新机制。原位同步辐射X射线衍射、电化学测量和理论计算相结合表明，二维MOF中Ni中心的动态电子态能够在充放电过程中调节多硫化物与MOF之间的相互作用，从而导致多硫化物具有强吸附和快速转化动力学。由此得到的室温钠硫电池是迄今为止报道的最稳定的电池之一，这表明新机制为高性能金属硫电池的发展开辟了一条有前景的途径。
