Ceramic composite diaphragm coated electrode, double-electric-layer capacitor and preparation method of double-electric-layer capacitor

The invention relates to the technical field of electric double-layer capacitors, and discloses a ceramic composite diaphragm coated electrode, an electric double-layer capacitor and a preparation method thereof, the ceramic composite diaphragm coated electrode comprises a current collector, and a porous carbon electrode layer, a ceramic coating and a diaphragm layer which are sequentially coated on both sides of the current collector; the thickness of the ceramic coating is 0.2 to 1.0 [mu] m; and the thickness of the porous carbon electrode layer is 60-150 [mu] m. The porous carbon electrode is coated with the ceramic coating, and the electrode, the ceramic and the diaphragm are compounded, so that oxygen-containing functional groups in the porous carbon of the electrode can be passivated, the thickness of the diaphragm can be reduced, the rated voltage of the double-electric-layer capacitor is improved, the capacity under unit volume/weight is improved, the energy density is greatly improved, and the high-v