Piling up Nano chips of dihydroxy composite metal oxide of cobalt and aluminum onto conductive substrate layer by layer in parallel. There are balance charges of negative ions. The method for preparing the material of film electrode includes steps: carrying out cleavage for dihydroxy composite metal oxide of cobalt and aluminum in insertion layer of glycine in formamide to obtain sol of Nano chips of dihydroxy composite metal oxide of cobalt and aluminum; then, pouring the sol to the conductive substrate layer with negative charges on surface processed in advance; vaporizing the solvent so as to prepare films of Nano chips of dihydroxy composite metal oxide of cobalt and aluminum. The membrane can be in use for electrode material of super film capacitor. Advantages are: high specific capacitance, good characteristic of multiplying factor, and better performance of electrochemical cycling. |