Intrinsic Kinetic Properties of Ternary Material for Lithium Ion Batteries Assessed by Single Particle Microelectrode

Authors

Yi-min WEI, Contemporary Amperex Technology Ltd.，Ningde 352100, Fujian, China;Follow

Corresponding Author

Yi-min WEI(WeiYiM@CATLBattery.com)

Abstract

Electrochemical performances such as capacity, rate, cycle and thermal stability of the nickel (Ni), cobalt (Co) and manganese (Mn) ternary cathode material, LiNi_xCo_yMn_zO₂ (x + y + z = 1), are significantly influenced by the proportion of Ni, Co, and Mn elements. To obtain higher specific capacity, LiNi_0.6Co_0.2Mn _0.2O₂ (NCM622) and LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811) with high amounts of Ni element were employed for the lithium ion batteries. By now, many studies have been focusing on the thermal and cycling stabilities of NCM622 and NCM811. However, there is lack of reports on the intrinsic kinetic properties of these two cathode materials. In this work, single particle microelectrode has been employed to investigate the intrinsic kinetic properties of NCM622 and NCM811 without the influences of binder, conductive agent, and electrode structure. Charge-discharge test, electrochemical impedance spectroscopy (EIS), and potentiostatic intermittent titration (PITT) methods were used for the evaluation of the kinetic properties of NCM622 and NCM811. Due to the increased Ni²⁺/Ni³⁺ and decreased Mn⁴⁺ amounts, the NCM811 material presented better kinetics properties and higher columbic efficiency compared with NCM622. The discharge capacity retention of NCM811 was above 80.8% at 20C compared to 0.5C, which is much higher than that of NCM622 with 68.6%.

Graphical Abstract

Keywords

ternary material, single particle microelectrode, electrochemical impedance spectroscopy, Li+ diffusion coefficient

DOI Link

https://doi.org/10.13208/j.electrochem.170209

Publication Date

2018-02-28

Online Available Date

2017-04-20

Revised Date

2017-03-19

Received Date

2017-02-07

Recommended Citation

Yi-min WEI. Intrinsic Kinetic Properties of Ternary Material for Lithium Ion Batteries Assessed by Single Particle Microelectrode[J]. Journal of Electrochemistry, 2018 , 24(1): 81-88.
DOI: 10.13208/j.electrochem.170209
Available at: https://jelectrochem.xmu.edu.cn/journal/vol24/iss1/9