Laser post-processing as a surface engineering strategy for atmospheric plasma-sprayed thin-film all-solid-state battery components

Abstract

The present study investigates laser post-processing as a method to tailor the surface properties of atmospheric plasma-sprayed (APS) anodes, solid electrolytes (SEs), and their half-cell configurations for all-solid-state batteries (ASSBs). Li4Ti5O12 (LTO) was used as the anode material, Li7La3Zr2O12 (LLZO) as the solid electrolyte, and aluminum as the substrate. APS was successfully employed to deposit single-layer LTO and LLZO thin films, as well as a double-layer LTO–LLZO half-cell configuration. XRD analysis showed that the as-sprayed LTO and LLZO coatings retained their characteristic crystalline phases without significant structural changes. Pulsed laser post-processing enabled effective surface smoothing of the plasma-sprayed ASSB components, while also inducing material remelting, partial ablation, and architecture-dependent effects. Single-layer and multilayer configurations responded differently due to variations in melting point, optical absorption, and heat flow pathways. Microstructural and elemental analyses using SEM/EDS and optical profilometry were conducted to evaluate the influence of laser surface modification. In addition, XPS confirmed that no changes in chemical state occurred between the as-sprayed and laser-processed LLZO coatings. Overall, this proof-of-concept study demonstrates the potential of laser post-processing to improve the surface quality of APS-sprayed ASSB components and provides useful insights for battery manufacturing and thermal spray communities.