The invention discloses an A / B / O three-position composite doped LLTO
solid electrolyte ceramic material and a preparation method thereof, aiming at A-position Li < + > ions of a Li < 0.33 > La < 0.56 > TiO < 3 >
ceramic material, high-valence ions M with high
electronegativity are adopted to carry out A-position
partial substitution, aiming at B-position Ti < 4 + > ions, low-valence ions Sb < 3 + > with high
electronegativity are adopted to carry out B-position
partial substitution, aiming at O-position O < 2-> ions, o-site
partial substitution is performed by adopting high-
electronegativity low-valence ions F <->, so that a stable and high-
conductivity cubic phase
crystal form of a high-electronegativity element is introduced, a
lithium ion channel is widened, the electronic insulation performance of the material is improved, an
electricity price compensation mechanism is triggered by utilizing non-equivalent substitution, more cation vacancy defects are generated in unit cells, and the performance of the material is improved. The
oxygen vacancy concentration at the
grain boundary is reduced by utilizing a
lattice oxygen transition mechanism, and positive charge enrichment at the
grain boundary is inhibited; and by utilizing the
electricity price difference between O < 2-> and F <->, cation vacancies with certain concentration are ensured to exist in unit cells, certain cation vacancies are formed at the
grain boundary, and the grain boundary
conductivity of the material is improved, so that a novel environment-friendly
solid electrolyte material with excellent comprehensive performance is formed. The preparation method is low in
sintering temperature, low in preparation cost, simple in process and easy to operate, influence factors are easy to control, and the preparation method is suitable for large-scale industrial production and beneficial to popularization and application.