LiBO2-modified LiCoO2 as an efficient cathode with garnet framework Li6.75La3Zr1.75Nb0.25O12 electrolyte toward building all-solid-state lithium battery for high-temperature operation

Garnet-based all-solid-state Li-ion batteries (ASSLIBs) suffer from high interfacial resistance at the cathode/electrolyte interface. Herein, we propose a LiBO2 (LBO) modification over a LiCoO2 (LCO) cathode to improve the interfacial contact and subsequently, the electrochemical performance of the cell. The High-Resolution Transmission Electron Microscopy (HR-TEM) images of the cathode particle show that the LiBO2 (LBO) content on the LCO surface effectively improves the electrode/electrolyte interface. In the cut-off voltage range of 3 - 4.3 V vs. Li, the LBO-LCO maintains 50% of its initial capacity (60 mAh g(-1)) after the 40th cycle, which is much higher than bare LCO in the ASSLIB configuration. The LBO layer over LCO enhances the Li-ion diffusion kinetics and eventually improves the electrochemical performance of the cell. To suppress the mechanical degradation of the electrode/electrolyte interface, we have reduced the working potential window to 3 - 4.1 V vs. Li, where the LBO-modified LCO provides an initial discharge capacity of 101 mAh g(-1) and assists in realizing improved cyclic performance in comparison with the conventional potential window. (C) 2020 Published by Elsevier Ltd.