Topic 01-22 : Development of the Fluidized Bed Chemical Vapor Deposition process to produce high performances battery materials

Up to now, no viable solution exists to uniformly coat active materials of batteries by passivating films. Already studied gas phase technologies such as PVD or ALD present intrinsic drawbacks non compatible with their use at large scale. The PhD thesis will focus on the FBCVD process in order to develop a high throughput, scalable technique for the coating of high performance battery materials, in environmentally and economically viable and scalable ways. The aspects of process development and thin film deposition and characterization will be investigated.

As the powders of interest may be difficult to fluidize, tuning an efficient fluidization process is a prerequisite to reach homogeneous coatings. Once this achieved, the next step will be the association of the fluidization process with a CVD one (SiO2 or Al2O3), already investigated by the applicants in other applicative fields and known in the literature for cathode materials protection (Culver, Janek et al. Adv. Energy Mater.; 9, 1900626, 2019). A relevant application among others will concern the cathode active material NMC (LiNixMnyCoz(x+y+z=1)O2) on which a thin, homogeneous coating is necessary to obtain optimal performances. The objective of this second step is to produce the proof of concept. The last step will investigate advanced coatings proposed by the industrial partner. The aim is to significantly improve cathode performances of general formula LiMxOy, starting with LiNbO3 coatings already known and widely used for SSB cathode materials (Ohta, Takada et al. Electrochemistry Communications; 9, 7, 2007). First electrochemical tests of the FBCVD coated NMC powders will be performed at CIRIMAT (P. Simon, P.L. Taberna), while several testing campaigns are planned at Umicore state of the art facilities. Those secondments are foreseen for a total duration of 3 months.