An investigation on strength distribution, subcritical crack growth and lifetime of the lithium-ion conductor Li7La3Zr2O12
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Due to the good chemical stability regarding lithium and cathode materials under high voltage, Li7La3Zr2O12 (LLZO) is considered as a promising electrolyte in all-solid-state Li-ion batteries. However, to enable stable long-term operation, knowledge of the mechanical boundary conditions is required. Since mechanical properties of the components and cells depend on the microstructure, the micro- and macro-mechanical properties of LLZO were investigated systemically via indentation tests and ring-on-ring bending (ROR) tests. Hence, fracture stress, elastic modulus, hardness and indentation fracture toughness of the material were characterized under different applied loads. Additionally, room-temperature subcritical crack growth effects were studied on the basis of loading rate-dependent ROR test derived data in order to assess potential reliability issues of LLZO components under application-relevant conditions. A strength–probability–lifetime plot is derived on the basis of these fracture stress data. Complementary optical and electron microscopic investigations were carried out. The Weibull modulus of LLZO is 6, and the stress should not exceed 21 MPa for a lifetime of 3 years to warrant a failure probability of 1%.
Support was given by China Scholarship Council (CSC) of China and National Council for Scientific and Technological Development (CNPq) of Brazil. Hao Zheng thanks the financial support from OCPC (Office of China Postdoc Council). The authors would like to acknowledge Ms. T. Osipova, Dr. Y. Zou and Mr. R. Silva for their support in mechanical testing and for obtaining confocal images. The authors gratefully acknowledge Dr. E. Wessel, Dr. D. Grüner and Mr. M. Ziegner for structural characterization and Prof. L. Singheiser for his support.
- 23.Wolfenstine J, Allen JL, Sakamoto J, Siegel DJ, Choe H (2017) Mechanical behavior of Li-ion-conducting crystalline oxide-based solid electrolytes: a brief review. Ionics 24:1–6Google Scholar
- 33.Teixeira EC, Piascik JR, Stoner BR, Thompson JY (2007) Dynamic fatigue and strength characterization of three ceramic materials. J Mater Sci: Mater Med 18(6):1219–1224Google Scholar
- 37.Malzbender J, de With G (2001) The use of the loading curve to assess soft coatings. Surf Coat Technol 127(2–3): 265–272Google Scholar
- 39.Sergejev F, Antonov M (2006) Comparative study on indentation fracture toughness measurements of cemented carbides. Proc Estonian Acad Sci Eng 12(4):388–398Google Scholar
- 40.Carter CB, Norton MG (2007) Ceramic materials: science and engineering. Springer, BerlinGoogle Scholar
- 44.ASTM C (2007) 1239-07: Standard practice for reporting uniaxial strength data and estimating Weibull distribution parameters for advanced ceramics. ASTM International, West ConshohockenGoogle Scholar
- 46.Standard A (2005) C1499-05, Standard test method for monotonic equibiaxial flexural strength of advanced ceramics at ambient temperature. ASTM International, West ConshohockenGoogle Scholar
- 47.Choi SR, Salem JA, Holland FA (1997) Estimation of slow crack growth parameters for constant stress-rate test data of advanced ceramics and glass by the individual data and arithmetic mean methods. Nasa Technical Memorandum, 107369Google Scholar
- 52.Chiang Y-M, Birnie DP, Kingery WD, Newcomb S (1997) Physical ceramics: principles for ceramic science and engineering, vol 409. Wiley, New YorkGoogle Scholar
- 54.Wang CH (1996) Introduction to fracture mechanics. DSTO Aeronautical and Maritime Research Laboratory Melbourne, MelbourneGoogle Scholar