Electrochemically induced synthesis of phosphates on metallic substrates

The emergence of electric vehicles (EVs) is the result of continuous efforts in the development of lithium-ion batteries (LIBs) with significant progress in improving of the battery capacity, the charge/discharge speed, and its safety. The next generation LIBs are expected to no longer contain liquid electrolytes, but instead contain solid electrolytes. Lithiated metal phosphates are common materials used in LIBs as cathodes (LiFePO₄), solid electrolytes (LiPON), and even as anodes. They benefit from advantages in large electrochemical stability and low cost.

In this master thesis project, you will investigate electrochemically induced synthesis for the fabrication of phosphate thin films on metallic substrates by method. This method was recently optimized in our group for the fabrication of dense coatings. Electrochemically controlling the pH near the electrode surface, allows a precipitation reaction to be localized, and a film of the precipitate can be formed on the surface. This method enables synthesis of thin films of otherwise electrochemically inactive materials [1]. An understanding of the reaction mechanism will be developed, with an emphasis on the initial stages of precipitation and film formation. The size and number density of precipitated nuclei depends strongly on, among other factors, the local pH, the surface energy and the supersaturation and will strongly influence the film crystallinity and properties. Thus, understanding the exact influence of these parameters allows one to engineer the film morphology and its properties. The films will be characterized by means of Fourier-Transform Infrared Spectroscopy, Scanning Electron Microscopy, Elastic Recoil Detection, X-ray Diffraction, Electrochemical Impedance spectroscopy, etc.

[1] Chem. Mater. 2021, 33, 7075−7088