wherein the electrochemical device comprises a solid-state electrolyte,

wherein the solid-state electrolyte comprises membrane material(s) and electrolyte salt(s), wherein, the membrane material(s) comprises an organic phase formed of polymeric material(s), the organic phase comprises a three-dimensionally interconnected interface and has a specific interfacial area greater than or equal to 1×10⁴ cm²/cm³, and the electrolyte salt(s) is dissolved in the organic phase,

wherein the solid-state electrolyte is prepared according to the following:

spraying solution(s) of the polymeric material(s) onto a selected receiving surface using electrostatic spinning technique to form primary structure(s) in the form of fibers and causing the primary structure(s) in the form of fibers to aggregate and form three-dimensional secondary structure(s), then treating the secondary structure(s) under pressure to be more dense to give the organic phase as the membrane material(s); or spraying solution(s) of the polymeric material(s) onto a selected receiving surface using electrostatic spinning technique to form primary structure(s) in the form of fibers and causing the primary structure(s) in the form of fibers to aggregate and form three-dimensional secondary structure(s), and at the time of performing electrostatic spinning, spraying dispersion liquid(s) of inorganic particles onto the selected receiving surface using electrostatic spraying technique to obtain a composite material constituted by the organic phase composed of the polymeric material(s) and the inorganic particles, then treating the composite material under pressure to be more dense to serve as the membrane material(s); and

dropwise adding or spraying solution(s) of the electrolyte salt(s) into the membrane material(s); or, immersing the membrane material(s) in the solution(s) of the electrolyte salt(s), then dried to remove solvent to obtain the solid-state electrolyte.