储能科学与技术 ›› 2023, Vol. 12 ›› Issue (8): 2361-2369.doi: 10.19799/j.cnki.2095-4239.2023.0128

• 储能材料与器件 • 上一篇    下一篇

LiF添加剂改善含锂陶瓷隔膜与4.35 V LiNi0.8Co0.1Mn0.1O2 正极的界面稳定性

黄永浩1,2(), 臧国景2, 朱霨亚1, 廖友好1,2(), 李伟善1,2()   

  1. 1.潮州三环(集团)股份有限公司,广东 潮州 515646
    2.华南师范大学化学学院,广东 广州 510006
  • 收稿日期:2023-03-15 修回日期:2023-04-07 出版日期:2023-08-05 发布日期:2023-08-23
  • 通讯作者: 廖友好,李伟善 E-mail:731581530@qq.com;liaoyh@scnu.edu.cn;liwsh@scnu.edu.cn
  • 作者简介:黄永浩(1998—),男,硕士研究生,研究方向为电池固体电解质材料,E-mail:731581530@qq.com
  • 基金资助:
    “潮州市陶瓷产业人才振兴计划”创新创业团队引进项目(2021YJ01)

Enhancing interfacial stability between lithium-containing ceramic separator and 4.35 V LiNi0.8Co0.1Mn0.1O2 cathode through LiF additives

Yonghao HUANG1,2(), Guojing ZANG2, Weiya ZHU1, Youhao LIAO1,2(), Weishan LI1,2()   

  1. 1.Chaozhou Three-circle (Group) Co. Ltd, Chaozhou 515646, Guangdong, China
    2.School of Chemistry, South China Normal University, Guangzhou 510006, Guangdong, China
  • Received:2023-03-15 Revised:2023-04-07 Online:2023-08-05 Published:2023-08-23
  • Contact: Youhao LIAO, Weishan LI E-mail:731581530@qq.com;liaoyh@scnu.edu.cn;liwsh@scnu.edu.cn

摘要:

锂离子电池用LiNi0.8Co0.1Mn0.1O2(NCM811)正极,具有较高比容量和较低成本的优点,但是其在高电压长循环时正极界面极不稳定、安全性能亟待提高。虽然锂快离子导体Li1.2Ca0.1Zr1.9(PO43制备的陶瓷隔膜在很大程度上可以解决电池的安全性问题,但是与NCM811正极界面稳定性差。本工作通过在陶瓷隔膜中添加具有稳定界面功能的氟化锂(LiF)的方法来解决此问题。采用扫描电子显微镜(SEM)、热重分析(TGA)、差示扫描量热法(DSC)、机械拉伸强度、热收缩、吸液率、电化学阻抗谱(EIS)、线性扫描伏安法(LSV)和充放电测试等方法进行表征。结果表明,当LiF占涂覆无机陶瓷颗粒总质量的10%时,得到的陶瓷隔膜性能最佳:具有良好的离子传输性能(室温离子电导率提高至9.5×10-4 S/cm)和最佳的界面稳定性。隔膜组装的Li||LiNi0.8Co0.1Ni0.1O2扣式电池在3.0~4.35 V的高电压范围以0.3 C倍率循环400次后,放电比容量从195.2 mAh/g减少到119.9 mAh/g,保持初始容量的61.4%,而没有添加LiF的陶瓷隔膜电池仅为32.7%。含LiF的陶瓷隔膜提升电池循环稳定性的原因是形成了高质量的高压正极/电解质界面膜,稳定了正极与陶瓷隔膜的界面,使正极材料在高电压下仍能保持结构的稳定。因此,本工作制备的陶瓷隔膜为NCM811正极在高电压锂离子电池中的商业化应用提供了一种便捷方法。

关键词: 含锂陶瓷隔膜, 氟化锂, LiNi0.8Co0.1Mn0.1O2正极, 电极/隔膜界面, 高电压, 锂离子电池

Abstract:

LiNi0.8Co0.1Mn0.1O2 (NCM811) cathodes in lithium-ion batteries have the advantages of high specific capacity and relatively low cost. However, long-term cycling at high voltage poses challenges to the cathode interface, leading to instability and a need for improved safety performance. Although the lithium fast ion conductor Li1.2Ca0.1Zr1.9(PO4)3 ceramic separator can considerably enhance battery safety, it exhibits poor interface stability when paired with NCM811 cathode. Herein, a lithium fluoride (LiF) additive with a stable interface function is added to the ceramic separator to solve this problem. The LiF-modified ceramic separator was characterized using scanning electron microscopy, thermogravimetric analysis, differential scanning calorimetry, mechanical tensile strength, thermal shrinkage, electrolyte uptake ability, electrochemical impedance spectroscopy, linear sweep voltammetry, and charge-discharge testing. The results show that the ceramic separator performs best when LiF accounts for 10% of the total mass of coated inorganic ceramic particles. It exhibits improved ionic transport properties, with room temperature ionic conductivity of 9.5×10-4 S/cm and excellent interfacial stability. In a Li||LiNi0.8Co0.1Ni0.1O2 coin cell operating in the high-voltage range of 3.0—4.35 V, the discharge-specific capacity decreases from 195.2 to 119.9 mAh/g at a 0.3 C rate after 400 cycles, while maintaining 61.4% of the initial capacity when using LiF-contained ceramic separator. In contrast, the capacity retention of the cell without LiF is only 32.7%. The enhanced cycling stability of the battery using a LiF-contained ceramic separator can be ascribed to the formation of a high-quality, high-voltage cathode-electrolyte interface film, stabilizing the interface between the cathode and separator, thereby preserving the structural stability of the cathode material under high voltages. Therefore, the developed ceramic separator in this study provides a convenient method for commercializing NCM811 cathodes in high-voltage lithium-ion batteries by enhancing interfacial stability and cycling performance.

Key words: lithium-containing ceramic separator, lithium fluoride, LiNi0.8Co0.1Mn0.1O2 cathode, electrode/separator interface, high-voltage, lithium-ion batteries

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