Acta Physico-Chimica Sinica ›› 2019, Vol. 35 ›› Issue (4): 361-370.doi: 10.3866/PKU.WHXB201805102

• REVIEW • Previous Articles     Next Articles

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)

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