Water-stable lithium ion conducting solid electrolyte of iron and aluminum doped NASICON-type LiTi2(PO4)3

High lithium ion conductivity solid electrolytes of Li1.4FexAl0.4 (-) Ti-x(1.6)(PO4)(3) (x = 0-0.4) with the NASICON-type structure were synthesized by using a sol-gel precursor. The highest electrical conductivity was obtained for Li1.4Fe0.25Al0.15Ti1.6(PO4)(3) sintered at 1040 degrees C for 7 h in air. The total, grain boundary, and bulk conductivities of the pellet were 1.01 x 10(-3), 2.17 x 10(-3) and 1.81 x 10(-3) S cm(-1) at 25 degrees C, respectively. The contribution of electron (or hole) conductivity to the total conductivity was negligibly small. Li1.4Fe0.25Al0.15Ti1.6(PO4)(3) was unstable in water, but stable in saturated LiOH and LiCl aqueous solutions. (C) 2014 Elsevier B.V. All rights reserved.