Synthesis of lithium difluoro(oxalate)borate(LiODFB), phase diagram and ions coordination of LiODFB in dimethyl carbonate  

二氟草酸硼酸锂(LiODFB)的制备及其在碳酸二甲酯中的相图和离子缔合规律（英文）

作　　者：ZHOU Hong-ming XIAO Kai-wen LI Jian XIAO De-min JIANG Yi-xiong 周宏明;肖凯文;李荐;肖德敏;蒋逸雄

机构地区：[1]School of Materials Science and Engineering Central South University [2]Hunan Zhengyuan Institute for Energy Storage Materials and Devices

出　　处：《Journal of Central South University》2018年第3期550-560,共11页中南大学学报（英文版）

基　　金：Project(51371198)supported by the National Natural Science Foundation of China;Project(K1202039-11)supported by the Science and Technology Project of Changsha,China

摘　　要：A new two-step synthetic method was successfully developed to simplify the recrystallization process of lithium difluoro(oxalate)borate(LiODFB).Meanwhile,the purity of LiODFB as-prepared was determined by NMR,ICP-AES and Karl Fisher measurements,respectively.The as-prepared LiODFB presents a high purity up to 99.95%.Its metal ions and water contents are under good control as well.Besides,its structure information and thermal properties were confirmed by FTIR,Raman and DSC-TGA analyses,respectively.LiODFB exerts fine thermostability and hypo-water-sensitivity and its structure information agrees well with previous literature.Furthermore,a combination of phase diagram and Raman spectroscopy were utilized to study the thermal phase behavior and ions coordination of LiODFB-DMC binary system to optimize the synthesis and recrystallization process.Although there are three types of molecular interaction forms(CIPs,AGG-IIa,AGG-IIIb)in LiODFB-DMC binary system,LiODFB can only be isolated as large single crystal solvate as LiODFB·(DMC)3/2 by slowly cooling subjected to the nucleation kinetics.Therefore,the fundamental information of our work is helpful in accelerating the application of LiODFB in Li-ion secondary batteries.本文介绍了一种新型两步合成法合成二氟草酸硼酸锂,简化了LiODFB的重结晶分离过程。通过NMR、ICP-AES以及卡尔费休法测定所制备的Li ODFB的纯度,结果表明,制备的LiODFB纯度高达99.95%,所含金属离子及水分均得到了很好的控制。此外,采用FTIR、Raman和DSC-TGA分析了LiODFB的结构信息及热力学性质,发现LiODFB具有非常优异的热力学稳定性和较低的水分敏感性,并且其结构信息与文献报道一致。另外,结合相图以及拉曼光谱技术研究了LiODFB-DMC二元体系的热力学相转变和离子规律,用来指导优化LiODFB的合成及重结晶工艺。结果表明,尽管在LiODFB-DMC二元体系中存在3种类型的分子间相互作用形式(CIPs,AGG-Ⅱa,AGG-Ⅲb),但受成核动力学条件影响,LiODFB仅可以通过缓慢冷却的方式获得较大的单晶溶剂化物—LiODFB·(DMC)_(3/2)。本文所提供的基础数据有助于推动LiODFB在锂离子电池领域的应用。

关 键 词：lithium difluoro(oxalate)borate two-step synthesis recrystallization phase diagram ions coordination 

分 类 号：TQ261.1[化学工程—有机化工]