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

Abstract

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 Li_xMn₂O₄ 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 Li_xMn₂O₄ thin films, with (x) values of 1 and 0.7, aimed at improving chemical stability and overall performance.

The epitaxial Li_xMn₂O₄ 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.