化工学报 ›› 2021, Vol. 72 ›› Issue (1): 609-618.DOI: 10.11949/0438-1157.20200836

• 材料化学工程与纳米技术 • 上一篇    下一篇

硼高效掺杂LiNi0.5Co0.2Mn0.3O2正极材料及其性能提升机制

朱华威(),余海峰,江仟仟,杨兆峰,江浩(),李春忠   

  1. 华东理工大学超细材料制备与应用教育部重点实验室,上海 200237
  • 收稿日期:2020-06-29 修回日期:2020-09-07 出版日期:2021-01-05 发布日期:2021-01-05
  • 通讯作者: 江浩
  • 作者简介:朱华威(1997—),男,博士研究生,649308505@qq.com
  • 基金资助:
    国家自然科学基金项目(21975074)

Synthesis and performance improvement mechanism of high-efficiency B doped LiNi0.5Co0.2Mn0.3O2 cathode materials for Li-ion batteries

ZHU Huawei(),YU Haifeng,JIANG Qianqian,YANG Zhaofeng,JIANG Hao(),LI Chunzhong   

  1. Key Laboratory for Ultrafine Materials of Ministry of Education, East China University of Science and Technology, Shanghai 200237, China
  • Received:2020-06-29 Revised:2020-09-07 Online:2021-01-05 Published:2021-01-05
  • Contact: JIANG Hao

摘要:

高键能异质原子的高效掺杂是稳定高电压LiNi0.5Co0.2Mn0.3O2(NCM)三元正极材料并提升其电化学性能的有效策略。借助含硼前体在二次颗粒表面富集及随后高温煅烧强化B3+体相扩散的策略,构建了硼离子高效掺杂NCM正极材料(NCM-B)。引入B—O键(键能:809 kJ·mol-1)抑制了电化学反应过程中晶格氧析出,进而稳定材料的氧离子框架;此外,表面残余的高锂离子导体Li2O-B2O3包覆层可以在一定程度上稳定电极-电解液界面。与改性前NCM相比,改性后的NCM-B正极材料在3.0~4.5 V电压区间的可逆比电容量可以达到193.7 mA·h·g-1,在10 C大功率下,比电容量仍保持120 mA·h·g-1(NCM仅为78.2 mA·h·g-1)。1 C下连续循环100圈后,比电容量保持率从73%提升到90%。表面富集和扩散强化的思想也有望实现其他正极材料的高效掺杂。

关键词: LiNi0.5Co0.2Mn0.3O2, 高电压, 硼掺杂, 锂离子电池

Abstract:

High-efficiency doping of strong-bonding energy heteroatoms is an effective strategy to stabilize high-voltage LiNi0.5Co0.2Mn0.3O2 (NCM) ternary cathode materials and improve their electrochemical performance. Herein, a strategy with boron-containing precursor surface enrichment and diffusion-reinforcement by high-temperature calcination is proposed to construct high-efficiency B-doped LiNi0.5Co0.2Mn0.3O2 cathode material (NCM-B). The high B—O bond energy (809 kJ·mol-1) greatly inhibits the evolution of oxygen atoms, hence steadying the oxygen ion framework. Moreover, the LiO2-B2O3 coating layer with high Li+ conductivity can stabilize the electrode-electrolyte interface. Compared with pure NCM, the NCM-B exhibits a high reversible capacity of 193.7 mA·h·g-1 within 3.0—4.5 V and delivers a superior high-rate performance of 120 mA·h·g-1 at 10 C (only 78.2 mA·h·g-1 for NCM). Furthermore, the capacity retention after 100 cycles at 1 C can be improved from 73% to 90%. The present surface-enrichment and diffusion-reinforcement strategy is expected to realize high-efficiency doping of other cathode materials.

Key words: LiNi0.5Co0.2Mn0.3O2, high voltage, B doping, Li-ion batteries

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