Na-doping approach for conductivity enhancement of natural phosphate derived fluorapatites

Abstract

The search for thermally stable solid electrolytes is promising for solid-state batteries. High ionic conductivity solid electrolytes derived from natural phosphate modified by sodium addition were developed. The samples were characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, 23Na solid-state nuclear magnetic resonance and scanning electron microscopy with energy dispersive spectroscopy. The structural and morphology changes were observed by increasing the Na2SO4 content. The synthesized ceramic electrolytes have low activation energy of about 0.60 eV and a relatively high ionic conductivity of 2 × 10−2 mS cm−1 at 400 °C.