| Abstract [eng] |
The influence of the structure and elemental composition of lithium solid electrolytes on their electrical properties are investigated in the dissertation. The technological conditions of lithium solid electrolyte ceramics‘ fabrication (synthesis and sintering) are described. Also the results of the investigation of crystal structure, microstructure, surfaces and electrical properties of the investigated ceramics are presented in the dissertation. The investigated materials belong to rhombohedral, hexagonal, monoclinic and cubic symmetries. A partial substitution of Al3+ by Y3+ in Li1.3AlyYx–yTi1.7(PO4)3 (x = 0.3; y = 0.1, 0.2) causes the increase in the lattice parameters and theoretical density of the compound. The results of X-ray diffraction analysis show that Li4xTi1-xP2O7 (x = 0.06, 0.1, 0.2) compounds have the same symmetry and space group as TiP2O7. The increase of lithium amount in the system Li4xTi1-xP2O7 slightly decreased the theoretical density of the compounds and increased lattice parameter. It was estimated, that trivalent and tetravalent titanium exists on the surfaces of NASICON-type and spinel ceramics. Total and bulk conductivity values and their activation energies of Li1+4xTi2-x(PO4)3, Li1.3AlyYx-yTi1.7(PO4)3 and Li1+4xTi2-xNbyP3-yO12 change with the variation of stoichiometric parameters x and y in the compounds. Anomalies of activation energy of total conductivity of pyrophosphate and spinel ceramics are observed. |
