The invention discloses a graded
sintering preparation method of silver
powder with a core-shell structure, which comprises the following steps: S1, preparing multi-stage silver seed crystals, namely preparing silver seed crystals with three characteristic particle sizes step by step by adopting a differential
liquid phase reduction method, namely first-stage seed crystals of 80nm, second-stage seed crystals of 150nm and third-stage seed crystals of 300nm; s2, gradient
coating sintering: mixing the three stages of seed crystals according to a
mass ratio of 3: 5: 2, and carrying out segmented treatment in
nitrogen-
hydrogen mixed gas; and S3, surface conductive treatment is conducted, specifically,
polythiophene with the molecular weight being 8000-12000 Da is dissolved in a 0.5 wt%
ethanol solution and stirred for 30 min, then
ZnO nanoparticles with the
doping concentration being 0.3 wt% are added, high-speed shearing dispersion is conducted for 60 min, it is ensured that the coverage rate is larger than or equal to 85%, a
mixed solution is obtained, finally, the silver
powder obtained in the step S2 is soaked in the
mixed solution,
ultrasonic dispersion is conducted for 10 min, and the surface activated silver
powder is obtained after
drying.