Application of cold spray to manufacturing of solid-state batteries

Abstract

May2025School of EngineeringAs current liquid electrolyte lithium-ion batteries reach their theoretical limit, exploration of solid-state batteries (SSBs) as an energy dense and safe alternative continues to expand. Due to many decades of research the stage is being approached where the main hurdle is how to manufacture high performance batteries at scale. Tantalum doped Lithium Lanthanum Zirconium oxide (LLZTO) is a solid electrolyte material of much interest, due to its high ionic conductivity and stability with lithium metal, which faces manufacturing challenges to its high sintering temperature. It is also commonly mixed with lithium cobalt oxide (LCO), a much-used cathode material, to increase ionic transport. In this study cold spray (CS), a kinetic spraying technique with a low process temperature capable of producing dense films, is investigated for its ability to create dense films of LLZTO and LCO. Single layer dense films of LLZTO with a thickness of around 12 µm were produced on an aluminium substrate. Attempts to produce a thicker film by depositing further layers of LLZTO were unsuccessful and caused large surface perturbations which allowed aluminium to come to the surface. LCO was likewise successfully deposited on aluminium and was able to form a 1µm thick film on Alumina. Both films experienced changes in crystallographic structure during deposition, and LLZTO displayed an increase in lattice strain which could affect electrochemical performance. Despite the immaturity of using this technique with solid state batteries, this study shows that with further development, cold spray could become a viable option to produce SSBs at large scale.M