含硫金属-有机框架及衍生物作锂硫电池正极材料的研究

With the increasing demand for energy storage system in today's society, the energy density of battery is required to be higher and higher. Lithium-sulfur batteries have a theoretical capacity of up to 1675 mA h g-1, which is about three to five times that of commercial lithium-ion batteries. However, the "shuttle effect" of sulfur makes it difficult for lithium-sulfur batteries to give full play to their advantages of high theoretical specific capacity, which is also the fundamental reason for limiting its industrial application. In this project, a new sulfur-containing metal-organic framework material (S-MOFs) was constructed by monometallic strategy and bimetallic strategy with organic ligands containing sulfur sites. We chose S-MOFs because of its adjustable pore size and the anchoring of highly homogeneous sulfur sites in open channels, which can effectively limit sulfur shuttle through-S-C- and-S-S-bond. We will explore the effects of the size of ligands and the number of sulfur-containing sites, the structure and morphology of the materials on the electrochemical properties of the materials. At the same time, we will pay attention to the construction of a new surface interface system of electrode materials and the redox mechanism. Taking S-MOFs as the synthesis center and controlling the attenuation of sulfur by multiple strategies, which may provide a theoretical and experimental basis for the development of a new generation of cathode materials for Li-S batteries with high specific capacity, long cycle and high safety performance.

随着当今社会对储能体系的需求越来越大，对电池的能量密度要求也越来越高。锂硫电池电池有高达1675 mAhg-1的理论容量，是商业锂离子电池的三到五倍左右。但是硫的“穿梭效应”使锂硫电池难以发挥其高理论比容量的优势，这也是限制其工业化应用的根本原因。本项目拟以含硫位点的有机配体通过单金属策略和双金属策略来构筑新型含硫金属-有机框架材料（S-MOFs）。我们选择S-MOFs是因其孔道尺寸可调，且可以使硫位点高度均一化的锚定于开放的孔道内，从而通过-S-C-键和-S-S-键有效地限制硫的穿梭。我们将探究配体的尺寸和含硫位点数目的变化、材料的结构和形貌差异对材料电化学性能的影响，同时注重构筑电极材料表界面新体系及氧化还原机理的研究。以S-MOFs为合成中心，多手段并用控制硫的衰减，为开发新型的具有比容量高、长循环和安全性能高的新一代锂硫电池正极材料提供理论与实验基础。

本项目立足于金属（簇）有机框架晶态材料这一前沿研究领域，利用含有硫或氮活性位点的有机配体，合成功能性晶态金属有机框架及其衍生物。在项目执行期间，成功合成多种金属（簇）有机框架晶态材料及其衍生物。对这些金属（簇）有机框架晶态材料的结构进行了详细的分析，研究了它们在储锂性能、能量转移和催化等方面的性质。通过本项目的研究，为金属（簇）有机框架晶态材料及其衍生物的实际应用提供了理论和实验基础。目前，在本项目的支持下，发表SCI学术论文12篇，其中项目负责人为第一作者或通讯作者的论文7篇。参与申请并授权发明专利4项。