Investigation of Zr doping and Electrochemical study on Li1+xTa1–xZrxSiO5 (<italic>x</italic> = 0–0.3) Solid Electrolyte for Lithium-Ion Battery

Materials with high lithium-ion conductivity are promising for use as electrolytes in solid-state batteries. However, several technical challenges, such as stability in air and optimal synthetic conditions, inhibit their extensive application. In this study, LiTaZrSiO5 solid electrolytes (SEs) are prepared at different sintering temperatures (900–1100°C) and characterized using X-ray diffraction, scanning electron microscopy, and electrochemical impedance spectrometry. Correlations among the sintering temperature, structural properties, and ionic conductivity of the LTSO SEs are examined systematically and discussed. According to the results, high ionic conductivity can be achieved by optimizing the sintering temperature of the SEs. The LTSO SE sintered at 1050°C exhibited the highest ionic conductivity. To further improve ionic conductivity, the sintering time was optimized in the range of 6–24 h. The conductivity improved as the sintering time increased from 6 to 12 h, and the best conductivity was achieved at 12 h. For sintering durations longer than 12 h, the conductivity of the material decreased. Further, doping emerged as a prominent strategy for increasing the ionic conductivity of the SEs. The effects of different concentrations of Zr dopant on the physio-chemical (structural, morphological) and electrochemical properties of the Li1+xTa1–xZrxSiO5 (<italic>x</italic> = 0–0.3) SEs were investigated. Compared to the results obtained for the other SEs, extraordinary results were obtained by doping the Li1.1Ta0.9Zr0.1SiO5 SE with zirconium, such as increased ionic conductivity, reduced charge transfer resistance, reduced crack formation, and increased SE particle size. In summary, the sintering temperature, sintering time, and dopant concentration in the synthesized Li1+xTa1–xZrxSiO5 (<italic>x</italic> = 0–0.3) precursors should be optimized to promote the development of LTZSO electrolytes suitable for use in future SSBs.