多晶及单晶高镍三元材料LiNi_(0.9)Co_(0.05)Mn_(0.05)O_(2)的可控制备及其电化学储锂特性  

Controllable synthesis and electrochemical mechanism related to polycrystalline and single-crystalline Ni-rich layered LiNi_(0.9)Co_(0.05)Mn_(0.05)O_(2)cathode materials

作　　者：张吉禄 董育辰 宋强[2] 袁思鸣[2] 郭孝东[3] ZHANG Jilu;DONG Yuchen;SONG Qiang;YUAN Siming;GUO Xiaodong(School of Chemical Engineering and Technology,Xi'an Jiaotong University,Xi'an 710049,Shaanxi,China;Institute of Naval Equipment,Beijing 100161,China;School of Chemical Engineering,Sichuan University,Chengdu 610065,Sichuan,China)

机构地区：[1]西安交通大学化学工程与技术学院,陕西西安710049 [2]海军装备研究院,北京100161 [3]四川大学化学工程学院,四川成都610065

出　　处：《储能科学与技术》2023年第8期2382-2389,共8页Energy Storage Science and Technology

基　　金：国家自然科学基金联合基金项目(U20A20145)。

摘　　要：随着电动汽车电源及储能技术的快速发展,高镍三元层状氧化物因其高容量和低成本等优势,成为动力电池首选正极材料之一,但是高镍三元材料面临循环性能和倍率性能差等问题,严重限制了其规模化应用。高镍单晶可以有效减缓颗粒裂纹的产生,从而提高高镍正极材料的循环稳定性,但是高镍单晶严苛的制备条件限制了其开发与应用。本工作通过共沉淀-高温固相法和熔盐法分别制备出多晶高镍材料LiNi_(0.9)Co_(0.05)Mn_(0.05)O_(2)(NCM-PC)和单晶LiNi_(0.9)Co_(0.05)Mn_(0.05)O_(2)材料(NCM-SC),并通过电子显微技术(SEM)、X射线粉末衍射仪(XRD)、恒电流间歇滴定技术(GITT)和电化学测试对两者的晶体结构、微观形貌、电化学性能及Li+传输动力学进行了系统研究。研究表明,NCM-PC具有较高的锂离子扩散系数,导致其优异的倍率性能,在10 C充放电倍率下,其放电比容量高达164 mAh/g。尽管NCM-SC的高倍率性能欠佳,但其循环性能优异,在3 C倍率下,经100次循环后其容量保持率高达89%。本研究为进一步探索单晶/多晶超高镍(Ni≥90%)正极材料尺寸调控及性能优化提供了参考。With the rapid development of technologies related to the power supply and energy storage in electric vehicles,Ni-rich layered oxides have become the most preferred cathode materials for application in power batteries owing to their high capacity and low cost.However,these layered oxides suffer from inferior cycling performance and poor rate capability,seriously impeding their practical application.Ni-rich single-crystalline can effectively mitigate the generation of particle cracking and improve the cycling stability of Ni-rich cathode materials;however,the severe preparation conditions of high nickel single crystals limit their development.Herein,polycrystalline Ni-rich LiNi_(0.9)Co_(0.05)Mn_(0.05)O_(2)(NCM-PC)and single crystalline LiNi_(0.9)Co_(0.05)Mn_(0.05)O_(2)(NCM-SC)were prepared via coprecipitation combined with the high-temperature solid-state and molten-salt methods,respectively.The crystallographic structure,microstructure,electrochemical properties and Li+diffusion kinetics of two cathode materials were systematically studied via scanning electron microscopy,x-ray diffractometry,constant current intermittent titration technique,and electrochemical tests.The results of this study demonstrate that NCM-PC possesses a relatively high lithium-ion diffusion coefficient,resulting in excellent rate performance.For instance,NCM-PC could deliver a discharge capacity of 164 mAh/g at 10 C.Although NCM-PC exhibits a low discharge capacity at a high C-rate,it exhibits an outstanding cycling performance with capacity retention of~89%after 100 cycles at 3 C.This study provides a theoretical basis for optimizing the particle size and electrochemical performance of single-crystalline/polycrystalline NCM materials having high Ni content(≥90%).

关 键 词：锂离子电池 超高镍正极材料 单晶 多晶 倍率性能 

分 类 号：TM911.3[电气工程—电力电子与电力传动]