Exploring Liquid Feedstock Thermal Spraying to Fabricate Solid State Thin Film Battery Components

Solid state thin film battery (SSTB) technology is garnering growing attention among battery manufacturers due to utilization of inorganic solid electrolytes that bear potential to impart greater longevity and improved safety compared to the conventional lithium-ion batteries. A wide spectrum of vacuum-based coating methods like pulsed laser deposition and magnetron sputtering have been investigated to develop SSTB components like anode, cathode, and solid electrolyte. However, these are typically expensive, characterized by slow deposition rate and yield mostly amorphous coatings that demand post-processing to enhance performance. Therefore, other innovative coating approaches that can overcome these shortcomings are desirable. In this context, liquid feedstock thermal spraying techniques relying on suspensions and solution precursors as feedstock promise to provide technical as well as economic advantages. This paper discusses deposition of Li₄Ti₅O₁₂ (LTO) as anode, LiNi_1/3Co_1/3Mn_1/3O₂ (NMC111) as cathode and Li₇La₃Zr₂O₁₂ (LLZO) as electrolyte undertaken as a proof-of-concept study. Powders of all the above chemistries were procured, and suspensions prepared in-house utilizing different additives to enhance suspension stability. The influence of spray variables on density, crystallinity and microstructure has been assessed. Electrochemical performance has also been evaluated in case of few deposited layers that appear prima facie promising.