Novel Approaches in Cold Sintering Process for Solid-State Electrolytes: Microstructure and Electrochemical Properties

Abstract

This PhD thesis deals with the sintering of LATP Solid-State Electrolytes obtained at 150 ºC using the Cold Sintering Process (CSP). This technique has been complemented with in operando EIS monitoring. A new setup was designed to monitor the sintering process by EIS. This new setup has allowed the study of different aspects: (i) the optimum Transient Liquid Phase content that provides the best electrical properties and microstructure; (ii) the optimum Bi2O3 content that maximizes the performance of the LATP SSEs; (iii) the particle size that balances the electrical response and the microstructure obtained; (iv) the modification of the chemistry in the intergranular areas by the introduction of the LiOH:LiNO3 eutectic; (v) the influence of the variables that affect the sintering process. This work demonstrates that in operando EIS monitoring is a powerful technique that allows the optimization of the different variables that influence the final properties in the CSP.