Novel yttrium and silicon co‐doped Li1.3+x+yAl0.3−xYxTi1.7Siy(P1−yO4)3 solid electrolyte for lithium batteries: Effect on ionic conductivity and crystal structure

Abstract Doping of superfast ionic conductors like NASICON has been shown to boost ionic conductivity and the efficiency of lithium batteries. NASICON‐type yttrium and silicon‐doped lithium aluminum titanium phosphate (LATP) solid electrolytes have been synthesized via the conventional solid‐state method at different sintering temperatures. Their intrinsic physical, chemical, and electrochemical properties are analyzed using x‐ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, x‐ray photoelectron spectroscopy, and electrochemical impedance spectroscopy. Yttrium and silicon co‐doped LATP (LAYTSP) powder sintered at 900°C exhibits homogeneous hexagonal morphology and better crystallinity than the pure LATP solid electrolyte synthesized by the same methodology. LAYSTP demonstrated a higher ionic conductivity of 5.98 × 10 −6 S/cm at ambient conditions. Mixing 5%‐LiCl with LAYTSP‐900°C improved the ionic conductivity significantly up to 1.88 × 10 −4 S/cm. Cell viability testing demonstrated that our cells exhibit long‐term stability and are suitable for applications requiring sustained high voltages.