Advanced synchrotron micro characterization of laser post-processed plasma sprayed LLZO solid-state battery electrolyte

Abstract Garnet-type solid-state electrolytes such as Li 7 La 3 Zr 2 O 12 (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 Li 2 ZrO 3 and Li 2 CO 3 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.