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Mechanical Properties of Li7La3Zr2O12 and Li0.33La0.57TiO3
Many new types of high energy Li batteries may require a solid Li-ion conducting electrolyte. The major requirements for the solid Li-ion electrolyte are; high Li-ion conductivity, low electronic conductivity and good chemical/electrochemical stability. However, in many applications adequate mechanical properties are also relevant. For example, an electrolyte with a high shear modulus is required to prevent dendrite penetration when using a Li anode. At present information on the mechanical properties of two new promising solid Li-ion conductors; Li7La3Zr2O12 (LLZO) and Li0.33La0.57TiO3 (LLTO) is lacking. It is therefore the purpose of this talk to present some of the first information on the room temperature mechanical behavior of high density (>98% relative density) LLZO and LLTO. These include: hardness, elastic modulus, fracture strength, fracture toughness and thermal expansion. The results will compared to existing data for other solid Li-ion conductors and theoretical predictions. In addition, the methods to improve the mechanical behavior of LLZO and LLTO while retaining high ionic conductivity will be presented.