Effects of interstitial Li+ ions on the properties of novel Li4.08Zn0.04Si0.96O4 ceramic electrolyte

The aim of this work was to investigate the effects of interstitial ions in the novel Li4 + 2xZnxSi1 − xO4 (x = 0.04) compound prepared via sol gel method. The compound was indexed to the monoclinic unit cell in the space group P21/m and the chemical composition of the compound was very close to the designed composition. The introduction of two interstitial Li+ ions increased charge carrier concentration in the doped system resulting in an enhancement of conductivity by an order of magnitude as compared to that of the parent compound, Li4SiO4. The compound of Li4.08Zn0.04Si0.96O4 exhibited total conductivity values of 2.51 × 10− 5 S cm− 1 at ambient temperature and 3.01 × 10− 3 S cm− 1 at 500 °C. Ionic transference number corresponding to Li+ ion transport was also found to be higher than the value obtained for the parent compound. This proved that interstitial Li+ ions contributed to the total conductivity in the sample. Linear sweep voltammetry result showed that the Li4.08Zn0.04Si0.96O4 ceramic electrolyte was electrochemically stable up to 5.80 V versus a Li/Li+ reference electrode.