Fine-tuning the microstructure for improved performance in cold-sintered Li1.3Al0.3Ti1.7(PO4)3 composite solid electrolytes

Solid-state electrolytes (SSE) are one of the fundamental components of the upcoming generation of batteries since they increase the operational safety and efficiency. In this work, composite solid electrolytes (CSE) based on Li1.3Al0.3Ti1.7(PO4)(3) and a (PEO2-LiTFSI) polymer matrix are obtained via the pioneering Cold Sintering Process (CSP), with a drastic reduction of the conventional sintering temperature. The CSP is performed at only 150 degrees C and 700 MPa, for 90 min of sintering time, by using a 3m acetic acid solution as the transient liquid phase (TLP). Here, the effect of the LATP particle size (d(50)) is studied to tailor the final microstructure, which enables the fine-tuning of the ultimate electrical properties of the electrolyte. An optimum d(50) of 0.415 mu m produces CSEs with 91 % of relative density, an ionic conductivity of 0.169 mS/cm, activation energy of 0.293 eV and electrical stability under 0.1 mA/cm(2), thus leading to competitive properties.