论文部分内容阅读
Solid lithium-ion conductors Li7-xLa3Zr2-xNbxO12 (x =0.25,0.5,1,1.5) with cubic gaet structure are successfully prepared by a solid state reaction method,and the effects of Nb concentration on lithium ion diffusion are investigated by means of inteal friction (IF) technique.A prominent relaxation-type IF peak (actually composed of two components) is observed in each Nb doped Li7La3Zr2O12 compound:with apeak PL at lower temperature and a peak PH at higher temperature.The mechanisms of the two components are suggested to be associated with two diffusion processes of lithium ions via vacancies:489 (-) 489 and 48g (-) 24d.The relaxational strength of the IF peak gradually decreases,which is accompanied by the activation energy increasing from 0.45eV to 0.64 eV with the increasing Nb doping level.The corresponding mechanism is ascribed to originate from lattice contraction as well as the lower concentration of diffusion ions induced by the substitution of Zr4+ by Nb5+.