Room temperature operation of all-solid-state battery using a closo-type complex hydride solid electrolyte and a LiCoO2 cathode by interfacial modification

We report on an all-solid-state battery that employs a closo-type complex hydride solid electrolyte and a LiCoO2 cathode. Interfacial modification between the solid electrolyte and cathode with a LiNbO3 buffer layer enables reversible charge-discharge cycling with a cell voltage of 3.9V (vs. Li+/Li) at room temperature. Electrochemical analyses clarify that the given modification effectively suppresses side reactions at the cathode/solid electrolyte interface. The interfacial resistance is lowered by ca. 10 times with a 5 nm thick LiNbO3 buffer layer compared to that without a buffer layer, so that a discharge capacity of 109 mAh g(-1) is achieved. These results suggest that interfacial modification can be a viable approach to the development of high-voltage all-solid-state batteries using closo-type complex hydride solid electrolytes and oxide cathodes. (C) 2019 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights reserved.