NASICON solid electrolyte coated by indium film for all-solid-state Li-metal batteries

The application of all-solid-state Li-metal batteries with solid oxide electrolytes is hindered by interfacial issues, especially the solid electrolyte/Li-metal interface. This work introduced a uniform indium film layer on the surface of Na+ super ionic conductor (NASICON) solid electrolyte Li1.5Al0.5Ge1.5P3O12 (LAGP), which promotes the intimate contact between Li metal and solid electrolyte and hinders the side reactions at the interface. Electrochemical impedance spectra show that the battery with coated solid electrolyte presents a smaller interfacial resistance and maintains stability after a long cycling time. By contrast, the baseline battery with a pure LAGP pellet shows a contact loss after cycling with the vibration of interfacial impedance. The Li symmetric cells with indium-modified solid electrolyte present stable cycling behavior over 400 h at 0.1 and 0.2 mA·cm−2. The all-solid-state Li-metal batteries with a Li anode, indium coating LAGP and two kinds of cathodes, namely carbon nanotubes (CNTs) and LiNi0.8Co0.1Mn0.1O2 (NCM811), are prepared and tested. The CNTs cathode for Li–O2 and Li–air batteries has a higher specific capacity than traditional Li-ion battery cathodes. The Li-NCM811 batteries deliver an initial Coulombic efficiency of about 75%, with 82% capacity retention after 20 cycles.