▎ 摘　　要

NOVELTY - Preparing graphene/sodium manganate flexible film comprises e.g. (i) adding manganese(III) oxide into a solution of sodium hydroxide solution, stirring, transferring the manganese(III) oxide solution into a hydrothermal reactor, washing and drying, (ii) adding graphene oxide into a deionized water, ultrasonic dispersing, (iii) adding sodium manganese oxide powder, vacuum filtering, cleaning, drying, immersing the microporous membrane and filter products in a specific solvent and peeling off the microporous membrane to obtain graphene oxide/sodium manganate flexible film, and (iv) drying. USE - The method is useful for preparing graphene/sodium manganate flexible film (claimed). ADVANTAGE - The method: produces product has sufficient toughness and can be cut directly as flexible electrode. DETAILED DESCRIPTION - Preparing graphene/sodium manganate flexible film comprises (i) adding manganese(III) oxide into a solution of 5 mol/l sodium hydroxide solution, stirring at stirring speed of 300-1200 rotations/minutes (rpm) for 30-150 minutes to obtain manganese(III) oxide solution, transferring the manganese(III) oxide solution into a hydrothermal reactor, maintaining constant temperature at 120-250 degrees C for 10-60 hours to obtain reaction product, washing the reaction product with distilled water for 3-5 times, drying at 50-100 degrees C for 5-12 hours to obtain sodium manganese oxide (Na4Mn9O18) powder, where the volume ratio of manganese(III) oxide and the volume of sodium hydroxide solution at a concentration of 5 mol/l is (1-2 mmol):30 ml, (ii) adding graphene oxide into a deionized water at room temperature and ultrasonic power is 800-1800 W and ultrasonic dispersing for 0.5-2 hours to obtain solution A, where the volume ratio of the graphene oxide and the deionized water is (20 -40 mg):10 ml, (iii) adding Na4Mn9O18 powder into a solution A, the ultrasonic power of 1000-2000 W, ultrasound dispersing for 1-3 hours, pouring on the microporous membrane for vacuum filtering for 3-5 hours, using distilled water to the micropore filter film and filtering the product, cleaning for 3-5 times, drying at 20-80 degrees C for 5-30 minutes, immersing the microporous membrane and filter products in a specific solvent for 10-120 minutes and peeling off the microporous membrane to obtain graphene oxide/sodium manganate flexible film, where the specific solvent is ethanol, acetone, diethyl ether and carbon tetrachloride, the microporous membrane is aqueous microporous membrane, the pore size is 0.1-1.2 mu m, the volume ratio of sodium manganese oxide powder and to the volume of solution A (10-30 mg):10 m, (iv) drying oxidized graphene/sodium permanganate flexible film at 200- 240 degrees C for 1-3 hours to obtain graphene/sodium manganate flexible film and the thickness of the graphene/sodium manganate flexible film is 10-50 mu m. An INDEPENDENT CLAIM is also included for method for preparing an aqueous sodium-zinc composite battery using a graphene / sodium manganate flexible film as raw material, cutting graphene/sodium manganate flexible film to obtain graphite oxide/sodium manganate flexible film with diameter of 1.1 cm, the diameter of 1.1 cm of graphene/ sodium manganate flexible film as the cathode, zinc sheet having diameter of 1.1 cm as cathode, using the mixture of sodium acetate and zinc acetate dehydrate as the electrolyte, the diameter of 1.2 cm glass fiber cotton for the diaphragm, together with the assembly of water sodium zinc composite battery and the water-containing sodium-zinc composite battery has charging/discharging voltage of 0.2-2.5 V.