This study investigates the phase and elemental distribution in a suspension plasma-sprayed (SPS) Li₄Ti₅O₁₂ (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 Li₄Ti₅O₁₂ phase was retained across most of the film, with localized transformations to secondary phases Li₂Ti₃O₇, Li₂TiO_3, and TiO₂ 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.

The astonishing safety and capacity characteristics of solid-state-batteries are encouraging researchers and companies to work on the manufacturing, development, and characterization of battery materials. In the present work, the effects of laser beam interaction with a liquid feedstock plasma-sprayed ceramic solid-state-battery (SSB) material coating were studied. Lithium Titanium Oxide (LTO) in the form of an aqueous suspension consisting of submicron powder particles was plasma-sprayed for the first time using a high-power axial III plasma torch on an aluminum substrate. The plasma-sprayed LTO coating suspension was subsequently post-processed using a fiber laser. The energy input of the laser beam on the surface of the deposited layer was the main variable. By varying the laser power and laser processing speed, the energy input values were varied, with values of 3.8 J/mm², 9.6 J/mm², 765.9 J/mm², and 1914.6 J/mm², and their effects on some key characteristics such as laser-processed zone dimensions and chemical composition were investigated. The results indicated that changing the laser beam parameter values has appreciable effects on the geometry, surface morphology, and elemental distribution of laser-processed zones; for instance, the highest energy inputs were 33% and 152%, respectively, higher than the lowest energy input.

Garnet-type solid-state electrolytes such as Li₇La₃Zr₂O₁₂ (LLZO) offer high ionic conductivity but present challenges in scalable processing due to phase instability and poor interfacial contact. In this study, LLZO thin-film coatings were fabricated via suspension plasma spraying (SPS) and subjected to laser-based thermal post-processing to improve surface and microstructural properties. Synchrotron micro-XRD, along with SEM, EDS, and surface profilometry was employed to analyze the effects of laser post-processing. Results reveal that laser processing reduced surface roughness by up to nearly 40%, eliminated the La(OH)₃ phase which is known to increase interfacial resistance, and led to the formation of Li₂ZrO₃ and Li₂CO₃ due to localized remelting. These findings highlight the dual role of laser post-processing in improving both morphological and chemical characteristics of SPS LLZO, offering a promising strategy to enhance solid electrode-solid electrolyte interface quality in solid-state battery architectures.

This study investigates the phase and elemental distribution in a suspension plasma-sprayed (SPS) Li4Ti5O12 (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 Li4Ti5O12 phase was retained across most of the film, with localized transformations to secondary phases Li2Ti3O7, Li2TiO3, and TiO2 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.