1:30 PM - ST05.01.06
Sodium Metal Mechanics—Temperature and Grain-Rotation Effects on Plasticity and Creep
William LePage1,2,Yuxin Chen2,Kuan-Hung Chen2,Andrea Poli2,Neil Dasgupta2
University of Tulsa1,University of Michigan2
Na-ion and Na-metal batteries are attractive alternatives to Li-ion, as they have the potential to reduce cost and add supply chain stability for energy storage portfolios. The raw materials for Na-based batteries are more readily sourced: Na is much more earth-abundant than Li, Na batteries can utilize aluminum for both current collectors (instead of copper), and they can also readily use cobalt-free cathodes. In order to advance the state-of-the-art for Na-ion and Na-metal batteries, reliable mechanical property data for Na is needed. However, few reports have characterized the mechanical properties of Na, especially in terms of its viscoplastic and creep properties –.
In this study, we report the first temperature-dependent measurements of power-law creep of Na. While prior works on the viscoplastic and creep deformation of Na have reported values at room temperature, this work measured the tensile response of Na in inert environments between 273 and 348 K. Furthermore, this work revealed insights about sodium deformation in general that have implications for Na batteries. For example, tests at room temperature utilizing digital image correlation (DIC) were performed inside of an argon glovebox  to map the local deformation of Na tensile samples. Local strain and rotation maps from DIC revealed millimeter-scale inhomogeneity that was attributed to plastic grain rotation, due to the large (~1 mm) grain size in the Na. The full calibration of power-law creep behavior from this work is valuable for modeling efforts to understand the fundamental research of Na-based batteries.
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