Exploring atmospheric plasma spraying as a pathway to fabricate solid-state battery constituents

Abstract

This study aims to demonstrate the feasibility of the atmospheric plasma spraying (APS) technique to fabricate individual constituents of solid-state batteries (SSBs) such as anode, solid electrolyte (SE) and cathode as well as further produce their half-cell (anode|SE) and full-cell (anode|SE|cathode) configurations. The materials targeted in this work were Li₄Ti₅O₁₂ (LTO) as an anode, Li₇La₃Zr₂O₁₂ (LLZO) as a SE and LiNi_1/3Mn_1/3Co_1/3O₂ (NMC111) as a cathode, with aluminium substrates being used as current collectors. The microstructure of the LTO and LLZO layers exhibited a characteristic lamellar structure along with the presence of a secondary phase attributed to delithiation at high temperatures, whereas the NMC111 layer was found to undergo substantial structural change. X-ray diffraction (XRD) analysis suggested that both LTO and LLZO layers retain most of the characteristic peaks along with the presence of secondary phases while NMC111 layers undergone significant change in the crystal structure. The XPS analysis confirms the presence of expected elements and oxidation states for the LTO layer. In the case of the LLZO layer, a metal carbonate surface reaction layer was observed, while the NMC111 layer reveals the presence of Li, Ni, Mn, Co, and O along with feeble metal carbonate. Fabrication of half-cell and full-cell configurations shows encouraging results by revealing a well-intact interface demonstrating the feasibility of the APS technique to accomplish such layered structures. This proof-of-concept effort provides valuable insights into the efficacy of APS for fabricating SSB components for further development, benefiting both the battery and thermal spray communities.