• Spectroscopy and Spectral Analysis
  • Vol. 41, Issue 10, 3021 (2021)
Hong-wei LIU1、* and Liang FU2、2; *;
Author Affiliations
  • 11. College of Material and Chemical Engineering, Hunan Institute of Technology, Hengyang 421002, China
  • 22. College of Materials Science and Engineering, Chongqing University, Chongqing 400045, China
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    DOI: 10.3964/j.issn.1000-0593(2021)10-3021-05 Cite this Article
    Hong-wei LIU, Liang FU. Analysis of Metal Impurity Elements in Li4Ti5O12 Through Microwave Plasma Atomic Emission Spectroscopy[J]. Spectroscopy and Spectral Analysis, 2021, 41(10): 3021 Copy Citation Text show less

    Abstract

    The spinel Li4Ti5O12 demonstrates high operating potential, excellent cycle life, and high safety as anode material of lithium-ion battery due to its negligible volume change, high thermal stability. The migration and deposition of metal impurities in Li4Ti5O12 are harmful degradation effects. In particular, magnetic metal impurities will cause the self-discharge and micro short circuit inside the battery, thereby affecting the safety performance and cycling life of the battery. A new method was proposed to determining the metal impurities in Li4Ti5O12 by microwave plasma atomic emission spectroscopy (MP-AES). The metal impurities of Mn, Na, Pb, Ni, Cr, Zn, K, Fe, Al, Mg, Cu, Ca, Co, and Cd was determined by MP-AES via dissolving the Li4Ti5O12 sample in aqua regia solution by microwave digestion without further filtration. The wavelengths of Mn 403.076 nm, Na 589.592 nm, Pb 405.781 nm, Ni 352.454 nm, Cr 425.433 nm, Zn 213.857 nm, K 766.491 nm, Fe 371.993 nm, Al 396.152 nm, Mg 285.213 nm, Cu 324.754 nm, Ca 393.366 nm, Co 340.512 nm, and Cd 228.802 nm was selected as the analytical line. Combined with the fast linear interference correction (FLIC) technology, the spectral interference and the background interference of all analytes was corrected. CsNO3 was added as an ionization suppression solution to correct the ionization interference caused by the easily ionized Li matrix. Y was used as the standard internal element to correct for signal intensity instability and matrix effects. The method detection limit (MDL) was 0.03~0.77 μg·g-1, the linear correlation coefficient was all greater than 0.999 3, the spiked recoveries were 96.4%~103%, and the relative standard deviations (RSDs) were less than 3.89%. The developed method was used to analyze the real sample and compared it with the national standard method (GB/T 30836—2014). Statistical analysis by the t-test method showed that at the 95% confidence level, there were no significant differences in most of the elements between the MP-AES and GB/T 30836—2014 methods, except for Zn, which further verifies the high accuracy of the method. Compared with inductively coupled plasma optical emission spectroscopy using argon as plasma gas, employing nitrogen as plasma gas can significantly reduce the operation cost. MP-AES has higher safety and better stability than atomic absorption spectroscopy using combustible gas. This method is simple to operate, low cost of analysis, high accuracy, and good precision. It provides a new method for the high-through put determination of multiple metal impurity elements in Li4Ti5O12.
    Hong-wei LIU, Liang FU. Analysis of Metal Impurity Elements in Li4Ti5O12 Through Microwave Plasma Atomic Emission Spectroscopy[J]. Spectroscopy and Spectral Analysis, 2021, 41(10): 3021
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