Effect of Film Thickness on the Kinetics of Lithium Insertion in LiMn₂O₄ Films Made by Multilayer Pulsed Laser Deposition for Thin‐Film All‐Solid‐State Battery Cathode Materials**

Abstract

Multi-layer pulsed laser deposition is a promising technique for producing LiMn 2 O 4 thin films for solid-state batteries. In this work, thin films are deposited with different numbers of pulses, leading to different thicknesses and grain sizes. We investigated "in operando" the kinetics of the Li þ transfer into LiMn 2 O 4 films by means of dynamic impedance spectroscopy. This technique allowed us to resolve the contributions of the reaction mechanism and of the transport phenomena, as well as to quantify their equivalent resistances. Surprisingly, with increasing film thickness, the charge transfer resistance increases while the apparent diffusion coefficient of lithium increases, leading to a decrease of the mass transport resistance. It appears that both these effects are related to the dimension of the crystals in the LiMn 2 O 4 thin films. These results provide new insights for an optimal tuning of the materials' preparation in view of maximizing their electrochemical performances.

Insights into the LiMn2O4 Cathode Stability in Aqueous Electrolytes

“…LMO thin films were fabricated by large area pulsed laser deposition with our well-established method of compensating Li losses with a multilayer deposition of LiMn 2 O 4 parent compound and Li 2 O acting as Li reservoir. ,− When grown on top of Pt-coated Si chips, this method produces relatively rough polycrystalline layers with high phase purity. For this experiment, a batch of 300 nm thick LMO films was produced (for details, see the Experimental section).…”

Recent Advances in Developing High-Performance Solid-State Lithium Batteries: Interface Engineering

“…(b) SEM pictures of deposited LiMn 2 O 4 thickness at 190, 340, and 1070 nm using PLD. This panel was reproduced with permission from ref . Copyright 2023 Wiley-VCH.…”

“…Erinmwingbovo et al 160 created LiMn 2 O 4 thin films with various pulse counts, resulting in variable thicknesses and grain sizes. The findings offer fresh insights into optimizing material preparation for the maximum electrochemical performance.…”