Localized Phase and Elemental Mapping in Solid-State Lithium Battery LTO Anode Thin-Film Produced by a Novel Suspension Plasma Spray Approach

Abstract This study investigates the phase and elemental distribution in a suspension plasma-sprayed (SPS) Li 4 Ti 5 O 12 (LTO) thin-film anode for solid-state lithium batteries, deposited on an SS-304 substrate. Advanced synchrotron-based µXRD and µXRF techniques were employed for micro-scale characterization, revealing distinct phase regions influenced by thermal exposure during the SPS process. The dominant Li 4 Ti 5 O 12 phase was retained across most of the film, with localized transformations to secondary phases Li 2 Ti 3 O 7 , Li 2 TiO 3, and TiO 2 near the substrate interface, primarily due to prolonged high-temperature exposure and subsequent lithium loss. These findings underscore the importance of controlling SPS parameters to minimize lithium loss and optimize phase stability and interfacial integrity in solid-state battery components.