物理化学学报 >> 2019, Vol. 35 >> Issue (4): 361-370.doi: 10.3866/PKU.WHXB201805102

综述 上一篇    下一篇

锂电池磷酸铁锂正极材料的结构与性能相关性的研究进展

胡江涛,郑家新,潘锋*()   

  • 收稿日期:2018-04-23 发布日期:2018-09-13
  • 通讯作者: 潘锋 E-mail:panfeng@pkusz.edu.cn
  • 作者简介:潘锋,1985年获北京大学化学学士学位,1994年获英国Strathclyde大学博士学位。现任北京大学深圳研究生院新材料学院院长、博导、“千人计划”特聘专家。研究方向为清洁能源及关键材料研发。国家材料基因组重点专项首席科学家
  • 基金资助:
    国家材料基因组重点专项(2016YFB0700600);广东省创新团队(2013N080)

Research Progress into the Structure and Performance of LiFePO4 Cathode Materials

Jiangtao HU,Jiaxin ZHENG,Feng PAN*()   

  • Received:2018-04-23 Published:2018-09-13
  • Contact: Feng PAN E-mail:panfeng@pkusz.edu.cn
  • Supported by:
    the National Materials Genome Project, China(2016YFB0700600);Guangdong Innovation Team Project, China(2013N080)

摘要:

磷酸铁锂(LiFePO4)具有环境友好、价格便宜、安全性能好等优点,作为正极材料已经广泛应用于国内的电动车动力电池中;为了进一步提高电池的性能,需要对影响磷酸铁锂及同类材料(LiMPO4 (LMP);M = Fe、Mn、Co、Ni及这些元素的混合)电化学性能的因素进行深入研究。本文从材料颗粒体相特征(相结构、掺杂、纳米化、缺陷和锂离子传输机制)、界面结构及在不同的电解质环境下的界面重构和电极结构与锂电池性能的构效关系等方面进行总结,系统化的阐述并总结了影响磷酸铁锂正极材料最新研究进展。

关键词: 锂离子电池, 正极材料, 磷酸铁锂, 结构, 性能

Abstract:

Lithium-ion batteries (LIBs) possess many virtues, such as low weight, a high energy density, and a long service life, and are regarded as an essential component of a low-carbon economy. Nowadays, LIBs are widely used in consumer electronics, as well as military and aviation products, and are the focus of significant research in the emerging field of energy materials. The cathode material is one of the most important parts of the LIB; its electrochemical performance plays an important role in the battery voltage, power/energy density, cycle life, and safety. LiFePO4 is a superior cathode material compared to spinel manganite (LiMn2O4) and layered lithium nickel-cobalt-manganese oxide (LiMO2 (M = Mn, Co, Ni)), and LiFePO4 has many advantages, such as excellent thermal stability, cycling performance, economic viability, and environmental friendliness. The theoretical diffusion coefficient of LiFePO4 is 10−8 cm2∙s−1, which is sufficient for Li+ de-intercalation in nanoparticles. However, the one-dimensional transport channels are easily blocked by structural defects, resulting in a lower diffusion coefficient and poor rate performance. The electronic conductivity of LiFePO4 is about 10−8 S∙cm−1, and this also limits the rate performance. Moreover, the low-temperature performance, low yield, and patent problems are also significant problems facing LiFePO4. In contrast, the stability and cost are not significant limitations to more extensive applications; rather, it is the energy density and power density that must be improved. To meet the above demands, in-depth research on the factors affecting the electrochemical performance of LiFePO4 is required. Many factors affect the electrochemical performance of LiFePO4, such as the synthetic method, particle size, electrolyte environment, electrode structure, and temperature. Based on the current state of research into LiFePO4, we have focused our review on the following three aspects: the characteristics of the nanoparticles, interface environment of the material, and the electrode structure. Finally, we summarize the relationship between the structure and electrochemical performance of LiFePO4 cathode materials: (1) the bulk phase characteristics of the material (phase structure, doping, nanocrystallization, defects, and lithium-ion transport mechanism), (2) interface structure and interface reconstruction under different electrolyte environments, and (3) the electrode structure. Our conclusions have great significance for future research.

Key words: Lithium Ion Battery, Cathode Materials, LiFePO4, Structure, Performance

MSC2000: 

  • O646