Epitaxial growth mechanism and structural characterization of spinel-type LixMn2O4 electrodes realized via pulsed laser deposition

Spinel-type lithium manganese oxide (LiMn2O4) is considered one of the most promising cathode materials for rechargeable batteries due to its high operating voltage, reduced toxicity, and lower cost compared to cobalt- based cathodes. However, the stability of LiMn2O4 is a significant challenge, as it tends to degrade over time, with manganese ion segregation leading to a reduction in battery capacity. The crystal structure of LixMn2O4 is highly dependent on the lithium content (x), and it can exist either in a single-phase or a two-phase form. These structural variations significantly affect the material's electrochemical performance. In this work, we present the growth and structural characterization of LixMn2O4 thin films, with (x) values of 1 and 0.7, aimed at improving chemical stability and overall performance. The epitaxial LixMn2O4 films were deposited using Pulsed Laser Deposition on different single-crystal substrates, including water-soluble Sr3Al2O6-buffered SrTiO3(100). Films grown on MgO(001) for both x = 1 and x = 0.7 exhibited excellent crystallographic quality, while films deposited on SrTiO3(001) showed good quality for x = 1, albeit with a slightly higher mosaic spread compared to those on MgO. Notably, for x = 0.7, a two-phase region was observed on the SrTiO3 and MgO substrates, where both phases shared the same structure but differed slightly in lattice parameters.