Lithium ion transport properties of high conductive tellurium substituted Li7La3Zr2O12 cubic lithium garnets

• Published in: Journal of power sources 2013-10, Vol.240, p.18-25
• Main Authors: Deviannapoorani, C., Dhivya, L., Ramakumar, S., Murugan, Ramaswamy
• Format: Article
• Language: English
• Subjects: Applied sciences; Crucibles; Cubic lattice; Demand; Direct energy conversion and energy accumulation; Doping; Electrical engineering. Electrical power engineering; Electrical power engineering; Electrochemical conversion: primary and secondary batteries, fuel cells; Exact sciences and technology; Garnets; Grain boundaries; Ionic conductivity; Lithium; Lithium garnets; Lithium ion battery; Sintering; Solid electrolytes
• ISSN: 0378-7753; 1873-2755
• DOI: 10.1016/j.jpowsour.2013.03.166

In this paper synthesis, structure and Li+ transport process of Li7−2xLa3Zr2−xTexO12 (x = 0.125 and 0.25) lithium garnets are reported. Preparation of high Li+ conductive Li7La3Zr2O12 (LLZ) in cubic phase by conventional solid state method demands sintering it around 1200 °C for 36 h in Al2O3 crucible. Cubic phase lithium garnet is successfully obtained at lower sintering temperature around 750 °C with the substitution of Zr4+ by Te6+ in the garnet lattice over the investigated composition range. Among the investigated compounds Li6.5La3Zr1.75Te0.25O12 sintered at 1100 °C exhibits a maximum room temperature total (bulk + grain boundary) ionic conductivity of 1.02 × 10−3 S cm−1. The present studies reveal the stabilization of the cubic garnet phase relatively at lower sintering temperature along with an enhancement in Li+ conductivity with lithium content lesser than 7 by suitable doping in Li7La3Zr2O12. •Fast Li+ conductive lithium garnets were obtained by Te substitution in Li7La3Zr2O12.•Cubic phase is successfully obtained at lower sintering temperature around 750 °C.•Li6.5La3Zr1.75Te0.25O12 exhibits a maximum Li+ conductivity of 1.02 × 10−3 S cm−1 at 30 °C.