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Evaluation of Mechanical Properties of Li2S-P2S5-based Glass Electrolytes with Li2O, P2O5 or LiI
Various properties such as stability or conductivity of Li2S-P2S5 glasses are changed by adding a third component to Li2S-P2S5 glasses. We reported that the addition of oxides as a third component to Li2S-P2S5 sulfide glasses improved the electrochemical stability and chemical stability in air [5,6]. On the other hand, lithium-ion conductivities of Li2S-P2S5 sulfide glasses are increased by adding LiI [7]. These sulfide glasses are thus attractive electrolytes to apply for all-solid-state batteries because of the superior stability or conductivity. However, their mechanical properties have not been investigated.
In this study, (70-x)Li2S·xLi2O·30P2S5 (x=0, 10, 20 mol%), 70Li2S·(30-y)P2S5·yP2O5 (y=0, 3, 10 mol%) and (100-z)(0.75Li2S·0.25P2S5)·zLiI (z=0, 5, 10, 20, 30 mol%) sulfide glass electrolytes were prepared by mechanical milling. The formability of the glass powders was investigated by powder compression tests. A partial substitution of oxides for sulfides lowered the formability of glasses, while the addition of LiI to sulfides improved the formability. Furthermore, Young’s moduli of these glasses were evaluated by ultrasonic wave velocity measurements. The Young’s moduli increased with an increase in the P2O5 content, while those decreased with an increase in the LiI content.
References
[1]A. Sakuda, A. Hayashi, and M. Tatsumisago, Chem. Mater., 22 (2010) 949.
[2]M. Tatsumisago and A. Hayashi, Funct. Mater. Lett., 1 (2008) 31.
[3]H. Kitaura, A. Hayashi, T. Ohtomo, S. Hama, and M. Tatsumisago, J. Mater. Chem., 21 (2011) 118.
[4] J.E. Ni, E.D. Case, J.S. Sakamoto, E. Rangasamy, and J.B. Wolfenstine, J. Mater. Sci., 47 (2012) 7978-7985.
[5] T. Ohtomo, A. Hayashi, M. Tatsumisago, and K. Kawamoto, J. Non-Cryst. Solids, 364 (2013) 57.
[6] K. Minami, A. Hayashi, and M. Tatsumisago, Solid State Ionics, 179 (2008) 1282.
[7] R. Mercier, J.P. Malugani, and B. Fahys, G. Robert, Solid State Ionics, 5 (1981) 663-666.