Influence of AlPO₄ Impurity on the Electrochemical Properties of NASICON‐Type Li_1.5Al_0.5Ti_1.5(PO₄)₃ Solid Electrolyte

Abstract Densification of ceramic electrolytes is a key enabler in producing electrolyte pellets for solid‐state batteries. This requires understanding the correlation between starting grain size electrolytes, chemical phase evolution and degree compaction which determine ion conductivity stability solid electrolytes. In our work we were able to optimize densification process LATP at 700 °C with high total ionic 3.45×10 −4 S cm −1 after hot pressing, balancing pristine crystallite AlPO 4 impurity formation. By combining several techniques such as situ heating X‐ray diffraction (XRD), scanning electron microscopy (SEM) nuclear magnetic resonance (NMR), explored formation mechanism during synthesis NASICON‐type Li 1.5 Al 0.5 Ti (PO ) 3 (LATP) showed effects annealing temperature on crystal material. Density functional theory (DFT) calculations imply metastable behaviour furtherly enhanced by particle nano‐structuring temperature. Our results point facile manufacturing towards energy dense safe battery technology.