Interphases Formation and Analysis at the Lithium–Aluminum–Titanium–Phosphate (LATP) and Lithium–Manganese Oxide Spinel (LMO) Interface during High-Temperature Bonding

In this study, fabrication processes of solid electrolyte/cathode interfaces for their use in next-generation all-solid-state lithium-ion battery (LIB) applications are described. Standard lithium–aluminum–titanium–phosphate (LATP) solid electrolyte and lithium–manganese oxide (LMO) spinel cathode ceramic half cells are assembled using two all-solid-state methods: a) co-sintering the cathode and electrolyte materials via field-assisted sintering and b) field-assisted high-temperature bonding. The morphology and composition of the interfaces are analyzed by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). This study reveals that the formation of interphases can be significantly decreased by separately performing the densification and joining procedures. Electrochemical impedance spectroscopy (EIS) is applied to understand and determine the effect of the manufactured interfaces on the system conductivity. Based on the results, it is concluded that the high-temperature bonding technique appears to be a suitable technique for future production of all-solid-state LIBs.