Atomic Layer Deposition of LixCoyOz Cathodic Thin Films for Li-Ion Batteries

Abstract

Atomic-Layer Deposition (ALD) is an appealing gas-phase technique for the deposition of thin solid cathodic films for 2D and especially 3D Li-ion microbatteries (Li-ion MBs). ALD relies on surface chemistry reactions and allows the fabrication of ultrathin pinhole free solid films with well controlled thickness, continuity and conformality. It has been shown to successfully cover 3D complex shapes for various applications including Li-ion MBs. Yet, a fairly low amount of work has been published on the realization by ALD of such cathodic active thin films. Typical cathodic materials are at least ternary compounds (including Lithium) which call for supercycles or multilayers approaches to synthesize them by ALD. As reminded for example by Maximov M. et al 1, the use of lithiated precursors complexifies the ALD fabrication due to, among others, Lithium high diffusivity and reactivity. In the case of LiCoO2 ALD synthesis for example, the only reported work to date is the one of Donders et al. 2 where the authors used CoCp2/LiOtBu as Cobalt/Lithium precursors respectively and O2 plasma as the oxidizing agent.The talk will describe the synthesis and characterizations of the LixCoyOzthin filmspreparedby a thermal ALD approach. It will detail the supercycle methods used as well as some of the investigations performed to explore the chemistry of the deposited films (Raman spectroscopy, X-Ray Photoelectron Spectroscopy, X-Ray Diffraction and Energy Dispersive X-Ray). The electrochemical performances of the films will also be shared and compared with the State of the art. 1 Maximov, M.; Nazarov, D.; Rumyantsev, A.; Koshtyal, Y.; Ezhov, I.; Mitrofanov, I.; Kim, A.; Medvedev, O.; Popovich, A. Atomic Layer Deposition of Lithium–Nickel–Silicon Oxide Cathode Material for Thin-Film Lithium-Ion Batteries. Energies 2020, 13, 2345. 2 Donders, M. E., ArnoldBik, W. M., Knoops, H. C. M., Kessels, W. M. M., & Notten, P. H. L. (2013). Atomic layer deposition of LiCoO2 thin film electrodes for all-solid-state Li-ion micro-batteries. Journal of the Electrochemical Society, 160(5), A3066-A3071.