Enhancing ionic conductivity of garnet-type Nb-doped Li7La3Zr2O12 by cerium doping*

We investigated the effect of additional doping with Ce on the ionic conductivity of the Nb-doped Li7La3Zr2O12 7 La 3 Zr 2 O 12 (LLZO) garnet ceramics using a combination of experimental and modeling approaches. Our results indicate that Ce doping can alter lattice parameters of the LLZNO, leading to the enhanced lithium ionic conductivity. The Ce, Nb co-doped LLZO (LLZNCO) structure with composition Li 6.5 La 3 Zr 1.5-x Nb 0.5 Ce x O 12 (x = 0.125) exhibits a lower activation energy (Ea a = 0.39 eV) than Li 6.5 La 3 Zr 1.5 Nb 0.5 O 12 (LLZNO) (Ea a = 0.41 eV). Furthermore, Ce doping leads to an increase in Li & thorn; & thorn; conductivity from 6.4 x 10-4-4 to 7 x 10-4-4 S/cm at room temperature. In addition, we discuss the diffusivity and conductivity of our samples using ab initio molecular dynamics simulations and propose possible mechanisms to explain the enhanced Li-ion conductivity caused by co-doping with Ce and Nb. Our results demonstrate that the LLZNCO ceramics are promising candidates for potential solid-state electrolytes for Li-ion batteries. (c) 2023 Chinese Society of Rare Earths. Published by Elsevier B.V. All rights are reserved, including those for text and data mining, AI training, and similar technologies.