Properties of novel Li4−3xCrxSiO4 ceramic electrolyte

Cr-doped Li4SiO4 compounds were prepared by a sol–gel method. The effects of Cr3+ doping on the characteristics of Li4SiO4 were carefully investigated. Compared with the XRD pattern of the Li4SiO4 sample, the XRD patterns of the Cr-doped Li4SiO4 shift to higher diffraction angle. This indicated that Cr3+ entered the structure of Li4SiO4 rather than forming impurities. The formation of the compound was confirmed by Fourier transform infrared study. The introduction of Cr3+ ions considerably raised the conductivity of the Li4SiO4 compound. The compound of Li3.94Cr0.02SiO4 exhibited total conductivity value of 2.51×10−5 S cm−1 at ambient temperature and 5.69×10−4 S cm−1 at 500 °C. Ionic transference number corresponding to Li+ ion transport determined by means of Bruce and Vincent technique was 0.95. Linear sweep voltammetry result showed that the doping of Cr3+ ion improved the limit of electrolyte decomposition to 4.51 V versus a Li/Li+ reference electrode.