The application belongs to the technical field of
new energy battery materials, and discloses a composite
solid electrolyte and a preparation method and
system thereof. The preparation method comprises the following steps: under an
inert atmosphere, a pretreated
sulfide solid electrolyte and a pretreated
halide solid electrolyte are put into a cavity; under the action of an
ultrasonic standing wave, the
sulfide solid electrolyte is suspended, and the
halide solid electrolyte is dispersed; a gradient
electric field in the vertical direction is formed through upper and lower
electrode plates in the cavity, so that the
halide solid electrolyte is coated on the
sulfide solid electrolyte, and the composite solid electrolyte is obtained. The method provided in the application realizes uniform
coating of LIC on LPSC, the
coating layer is uniform, the interface is firmly combined, the interface stability and the
oxidation resistance of LPSC are effectively improved, and the
ionic conductivity of LIC and LPSC is retained.