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Since the lithium-ion secondary batteries (LIBs) based on the LiCoO2 cathode materials, carbon based anode materials and organic liquid electrolyte have been commercialized, LIBs have been applied as power source for electric or hybrid vehicles beyond small IT applications. [1,2] As used in the large-scale energy storage devices, the safety of LIBs has given rise to more important issue. Therefore, the all-solid-state-batteries (ASSBs) with non-flammable inorganic solid electrolyte are one of the promising candidates.[3,4] Among the solid electrolyte materials, the sulfide-based solid electrolytes are widely used due to higher Li-ion conductivity and their soft property. Nevertheless, the ASSBs have been yet difficult to operate with the long cycle life and high current density despite the use of high Li-ion conducting solid electrolyte owing to the interfacial resistance and insufficient electrochemically active area. [5,6] Therefore, it is important to understand the interfacial characterization of solid-solid interface, especially the cathode and solid electrolyte in the composite cathode of ASSBs. Generally, the cathode materials and sulfide-based solid electrolytes have shown the large interfacial resistance from the space-charge layer and thus, as an effective approach to improve the electrochemical performance of ASSBs, the interfacial modifications for the cathode material by coating of LiNbO3, Li4Ti5O12, LiTaO3, and Li2O-SiO2 have been reported in previous studies. [5-7] Herein, the detailed microscopic observation and structural analysis for the interface between Li(Ni0.6Co0.2Mn0.2)O2 (NCM622) layered cathode materials and sulfide-based solid electrolyte are carried out and the comparison with pristine NCM622 and LiNbO3-coated NCM622 is also depicted. For this study, transmission electron microscopy (TEM) and energy dispersive X-ray spectroscopy (EDS) analysis have been mainly used. For further investigations, the electrochemical impedance spectroscopy and charge-discharge performance of the all-solid-state batteries using pristine and LiNbO3-coated NCM622 were demonstrated. References [1] J.B. GoodenoughAuthor Vitae, K.S. ParkAuthor VitaeAuthor VitaeAuthor VitaeAuthor Vitae, J. Am. Chem. Soc., 4 (2013) 1167-1176. [2] J.-Y. Hwang, S.-T. Myung, Y. K. Sun, Chem. Soc. Rev, 46 (2017) 3529−3614. [3] Y. Ito, M. Otoyama, A. Hayashi, T. Ohtomo, M. Tatsumisago, Journal of Power Sources, 360 (2017) 328-335. [4] N. Kamaya, K.Homma, Y.Yamakawa, M.Hirayama, R. Kanno. M. Yonemura, T. Kamiyama, Y. Kato, S. Hama, K. Kawamoto, A. Mitsui, Nat. Mater., 10 (2011), 628−686. [5] N. Ohta, K. Takada, I. Sakaguchi, L. Zhang, R. Ma, k. Fukuda, M. Osada, T. Sasaki, Electrochem. Commun., 9 (2007), 1486-1490. [6] Y. Seino, T. Ota, K. Takada, Journal of Power Sources, 196 (2011) 6488-6492. [7] A. Sakuda, H. Kitaura, A. Hayashi, K. Tadanaga, M. Tatsumisago, Electrochem. Solid-state Lett. 11 (2007) A1-A3 |
