With the advent of all-electric vehicle, increasing the range and reducing the production costs of lithium-ion batteries has become a priority for the automotive industry. For this purpose, one the most margins of progress consists in using, for the positive electrode, nickel-rich isotype lamellar oxides. In return, their use leads to a reduction of the thermal stability as well as the cycling capability. Both aspects are largely dependent of undesired phenomena occurring at the surface of these materials during cycling. Modifications provided at the structure or composition of the surface might enhance significantly the behavior of these high energy density materials. Faced with this issue, the process of Atomic Layer Deposition under vacuum (ALD) is a promising method to perform protective coatings and master their properties.
This thesis aims at performing surface modifications of these electrodes by ALD and studying the influence on the electrode and active material during cycling. For that, the student will have at her/his disposal two ALD equipment integrated into the same argon glovebox, in the new “Batterie” platform of CEA Tech Nouvelle-Aquitaine located at Pessac (France). Different techniques will be used, in collaboration with IPREM in Pau (France), to characterize the materials (e.g.: X-ray photoelectron spectroscopy, Auger microprobe, electronic microscopy, X-ray diffraction,…). The electrochemical behavior of coated materials, as well as the transport properties within the ALD thin films will be studied by galvanostatic cycling and impedance spectroscopy.