Study the preparation method of cathode foil of solid-state aluminum capacitor

A solid-state capacitor aluminum/carbon composite negative foil with the carbon layer weight less than 3 mg/cm2 and carbon/aluminum layer featuring with good interface adhesion and high specific capacitance is prepared by adding the pressing-in technique and the sol-gel idea based on the carbon coating technology on the paste. The microstructure and phase composition of the surface and interface of the aluminum/carbon composite foil are investigated by means of scanning electron microscope (SEM), and the effects of various composite carbon materials on the specific capacity of the negative electrode foil at different frequencies are discussed. The curve of the specific capacity of the negative electrode carbon foil with frequency is presented under the condition of different carbon slurry ratios. The results show that the pores on the surface of the carbon layer are developed, and the carbon layer and aluminum foils are closely combined, generating Al₄C₃ on the surface and forming a good metallurgical combination. When the ratio of full-carbon paste is 15:2:1:2, the combination of carbon/aluminum layer is greatly bonded and the specific volume is up to 2950x10^-6 F/cm² under the condition of 1kHz-0.3V. As the test frequency increases, the specific capacity attenuation is small.