The application relates to the technical field of
solid electrolytes, in particular to a co-doped
sodium-based
sulfide solid electrolyte and a preparation method and application thereof, wherein a Na2S-NaD nanoeutectic precursor is prepared by pre-high-energy ball milling of a
sodium source and
sodium halide, then the precursor is mixed with the remaining raw materials and sintered at a low temperature of 300-450 DEG C, so that the product forms a
nanocrystal-glass
composite structure which cannot be obtained by a traditional high-temperature
solid-
phase method. The unique structure can eliminate the inherent
grain boundary impedance of the crystalline material, provide isotropic and continuous three-dimensional transmission channels for sodium ions, significantly reduce the
diffusion barrier, and realize ultra-high
ionic conductivity far exceeding that of the same-component crystalline material. Meanwhile, the application realizes multi-element synergistic
doping by adopting the main group elements M of IV / V to partially replace the position of
phosphorus elements and co-substitute the cations with fixed
tungsten element
doping, so that the lattice can be stabilized, stress can be released, the sodium
ion diffusion barrier can be reduced, and the synergistic improvement of high air stability, high
structural stability and high
ionic conductivity can be realized.