Characterization of novel Li4Zr0.06Si0.94O4 and Li3.94Cr0.02Zr0.06Si0.94O4 ceramic electrolytes for lithium cells

Two ceramic electrolytes, Li4Zr0.06Si0.94O4 and Li3.94Cr0.02Zr0.06Si0.94O4, were prepared by a citrate sol–gel method. The structure, morphology, particle size, conductivity and electrochemical property were investigated. Both electrolyte materials had quite similar lattice parameters. The Li3.94Cr0.02Zr0.06Si0.94O4 exhibited higher total conductivity value of 1.83×10−4 S cm−1 at an ambient temperature and 1.13×10−3 S cm−1 at 500 °C which are an order of magnitude higher than those of Li4Zr0.06Si0.94O4. Ionic transference number corresponding to Li+ ion transport was 0.92 for Li4Zr0.06Si0.94O4 and increased to 0.97 for Li3.94Cr0.02Zr0.06Si0.94O4. The Li3.94Cr0.02Zr0.06Si0.94O4 sample showed a maximum discharge capacity of 103 mAh g−1 at the rate of 0.05 C in a potential range of 3.0–4.2 V.