Xu Fei, Yang Shuhao, Chen Xiong, Liu Qianhui, Li Hejun, Wang Hongqiang, Wei Bingqing, Jiang Donglin
State Key Laboratory of Solidification Processing , Center for Nano Energy Materials , School of Materials Science and Engineering , Northwestern Polytechnical University , Shaanxi Joint Laboratory of Graphene (NPU) , Xi'an , 710072 , P. R. China.
State Key Laboratory of Photocatalysis on Energy and Environment , College of Chemistry , Fuzhou University , Fuzhou 350116 , P. R. China . Email:
Chem Sci. 2019 May 7;10(23):6001-6006. doi: 10.1039/c8sc04518f. eCollection 2019 Jun 21.
The aligned one-dimensional channels found in covalent organic frameworks offer a unique space for energy storage. However, physical isolation of sulfur in the channels is not sufficient to prevent the shuttle of lithium-sulfide intermediates that eventually results in a poor performance of lithium-sulfur energy storage. Herein, we report a strategy based on imine-linked frameworks for addressing this shuttle issue by covalently engineering polysulfide chains on the pore walls. The imine linkages can trigger the polymerization of sulfur to form polysulfide chains and anchor them on the channel walls. The immobilized polysulfide chains suppress the shuttle effect and are highly redox active. This structural evolution induces multifold positive effects on energy storage and achieves improved capacity, sulfur accessibility, rate capability and cycle stability. Our results suggest a porous platform achieved by pore wall engineering for tackling key issues in energy storage.
共价有机框架中发现的排列整齐的一维通道为能量存储提供了独特的空间。然而，通道中硫的物理隔离不足以防止硫化锂中间体的穿梭，最终导致锂硫能量存储性能不佳。在此，我们报告一种基于亚胺连接框架的策略，通过在孔壁上共价构建多硫化物链来解决这一穿梭问题。亚胺键可引发硫的聚合以形成多硫化物链并将它们锚定在通道壁上。固定化的多硫化物链抑制了穿梭效应，并且具有高度的氧化还原活性。这种结构演变对能量存储产生了多重积极影响，并实现了容量、硫可及性、倍率性能和循环稳定性的提升。我们的结果表明，通过孔壁工程实现的多孔平台可解决能量存储中的关键问题。
