Composite electrolytes Li7La3Zr2O12-glassy Li2O-B2O3-SiO2

In this work, the influence of sintering additive (borosilicate glass, 65Li2O·27B2O3·8SiO2) on the density and total (bulk + grain-boundary) conductivity of the tetragonal Li7La3Zr2O12 (LLZ) has been investigated. Optimal temperature of the sintering was chosen as 1150 °C since the composite with 1 wt% of the glass has the highest density and total conductivity after annealing at this temperature. Then, series of composites Li7La3Zr2O12 - x wt% 65Li2O·27B2O3·8SiO2 (x = 1-10) were prepared. Relative density of the composite samples is higher than one of the sintered LLZ. The phase composition of each sample was characterized using X-ray diffraction; all reflexes are indexed as tetragonal LLZ. The conductivity of the composites was studied by complex impedance spectroscopy in the temperature range of 20-250 °C. The 65Li2O·27B2O3·8SiO2 glass addition of 3 wt% leads to an increase in the total conductivity of the samples by two orders of magnitude up from 2.6 ∙ 10− 7 to 1.5 ∙ 10− 5 S cm− 1 at 25 °C.