Tracer diffusion coefficients of Li+ ions in c-axis oriented LixCoO2 thin films measured by secondary ion mass spectrometry
| Autor: | Naoaki Kuwata, Takamichi Miyazaki, Yoshinori Tanaka, Kazunori Takada, Norikazu Ishigaki, Gen Hasegawa, Junichi Kawamura |
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| Rok vydání: | 2021 |
| Předmět: |
Range (particle radiation)
Materials science Analytical chemistry General Physics and Astronomy chemistry.chemical_element 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences Ion Secondary ion mass spectrometry chemistry Vacancy defect Lithium Physical and Theoretical Chemistry Thin film Diffusion (business) 0210 nano-technology Cobalt oxide |
| Zdroj: | Physical Chemistry Chemical Physics. 23:2438-2448 |
| ISSN: | 1463-9084 1463-9076 |
| DOI: | 10.1039/d0cp04598e |
| Popis: | Lithium diffusion is a key factor in determining the charge/discharge rate of Li-ion batteries. Herein, we study the tracer diffusion coefficient (D*) of lithium ions in the c-axis oriented LiCoO2 thin film using secondary ion mass spectrometry (SIMS). We applied a step-isotope-exchange method to determine D* in the Li-extracted LixCoO2. The observed values of D* ranged from 2 × 10-12 to 3 × 10-17 cm2 s-1 depending on the compositions in the range of 0.4 < x < 1.0. Approaching the stoichiometric composition (x = 1.0), D* decreases steeply to the minimum, which can be explained by the vacancy diffusion mechanism. Electrochemically determined diffusion coefficients corrected by thermodynamic factors are found to be in good agreement with D* determined by our method, over a wide range of compositions. The c-axis diffusion was explained by the migration of Li+ ions from one layer to another through additional diffusion channels, such as antiphase boundaries and a pair of Li antisite and oxygen vacancies in cobalt oxide layers. |
| Databáze: | OpenAIRE |
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