储能科学与技术 ›› 2023, Vol. 12 ›› Issue (8): 2382-2389.doi: 10.19799/j.cnki.2095-4239.2023.0171

• 储能材料与器件 • 上一篇    下一篇

多晶及单晶高镍三元材料LiNi0.9Co0.05Mn0.05O2 的可控制备及其电化学储锂特性

张吉禄1(), 董育辰1, 宋强2, 袁思鸣2, 郭孝东3()   

  1. 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
  • 收稿日期:2023-03-23 修回日期:2023-04-19 出版日期:2023-08-05 发布日期:2023-08-23
  • 通讯作者: 郭孝东 E-mail:zhang.jilu@stu.xjtu.edu.cn;xiaodong2009@scu.edu.cn
  • 作者简介:张吉禄（1998—），男，硕士研究生，研究方向为锂离子电池高镍三元正极材料，E-mail：zhang.jilu@stu.xjtu.edu.cn；
  • 基金资助:
    国家自然科学基金联合基金项目(U20A20145)

Controllable synthesis and electrochemical mechanism related to polycrystalline and single-crystalline Ni-rich layered LiNi0.9Co0.05Mn0.05O2 cathode materials

Jilu ZHANG1(), Yuchen DONG1, Qiang SONG2, Siming YUAN2, Xiaodong GUO3()   

  1. 1.School of Chemical Engineering and Technology, Xi'an Jiaotong University, Xi'an 710049, Shaanxi, China
    2.Institute of Naval Equipment, Beijing 100161, China
    3.School of Chemical Engineering, Sichuan University, Chengdu 610065, Sichuan, China
  • Received:2023-03-23 Revised:2023-04-19 Online:2023-08-05 Published:2023-08-23
  • Contact: Xiaodong GUO E-mail:zhang.jilu@stu.xjtu.edu.cn;xiaodong2009@scu.edu.cn

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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LiNi0.9Co0.05Mn0.05O2(NCM-PC)和单晶LiNi0.9Co0.05Mn0.05O2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。

关键词: 锂离子电池, 超高镍正极材料, 单晶, 多晶, 倍率性能

Abstract:

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 LiNi0.9Co0.05Mn0.05O2 (NCM-PC) and single-crystalline LiNi0.9Co0.05Mn0.05O2 (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 %).

Key words: lithium-ion battery, Ni-rich cathode, single-crystalline, polycrystalline, rate capability

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