▎ 摘　　要

NOVELTY - A three-phase composite electrode comprises sulfonated graphene, manganese dioxide, and manganese dioxide-poly (3,4-ethylene dioxythiophene)-polystyrene sulfonic acid. USE - Three-phase composite electrode for use in a vanadium battery (claimed). ADVANTAGE - The three-phase composite electrode can increase vanadium battery life and increase safety feature of vanadium battery. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for the following: (1) a method for preparing a three-phase composite electrode, which involves weighing certain amount of phosphorus pentoxide and potassium persulfate dissolved in concentrated sulfuric acid, adding graphite, reacting at 80 degrees C for 4-5 hours, cooling to room temperature, filtering, drying, obtaining solid A, mixing solid A and concentrated sulfuric acid at 0-5 degrees C in a molar ratio of 1:1, adding potassium permanganate, reacting for 2-3 hours after adding an appropriate amount of hydrogen peroxide to give a yellow precipitate, filtering a yellow precipitate and drying, weighing sulfanilic acid solution and 2 mass% sodium hydroxide solution according to mass ratio of 2:1 at 0 degrees C, adding sodium nitrite to sulfanilic acid hydrochloride with mole ratio of 20:1, dropwisely adding hydrochloric acid solution, obtaining white sediment, filtering and drying, homogeneously mixing yellow precipitate and sodium borohydride in molar ratio of 1:1.5 with water, adding obtained white precipitate to water according to mass ratio of 1:1.2, reacting at 0 degrees C for 5-6 hours, adding hydration hydrazine to obtained yellow precipitate with mole ratio of 1:1 to obtain sulfonated graphene dispersion liquid, adding sulfonated graphene dispersion liquid into indium-tin oxide glass, utilizing 0.1 mole/l manganese(II) sulfate solution as electrolyte and sulfonated graphene electrode as working electrode, silver/silver chloride as reference electrode, platinum filament as pair electrode, reacting at room temperature and at low 1 V voltage response for 5-6 minutes, obtaining sulfonated graphene/manganese dioxide composite electrode, taking 0.05 mole/l 3, 4-ethylene dioxide thiophene-styrene sulfonic acid solution, 0.1 mole/l sodium sulfate solution as support electrolyte, and sulfonated graphene/manganese dioxide as working electrode, silver/silver chloride as reference electrode, platinum filament as pair electrode, reacting at 1 V for 5-6 minutes and obtaining sulfonated graphene/manganese dioxide/poly(3, 4-ethylene dioxythiophene)-polystyrene three-phase composite electrode (2) use of three-phase composite electrode in vanadium battery, where the electrodes are provided on both sides of membrane, the bottom electrode is inserted into an electrolyte, ion-exchange membrane is multi-layer material, the electrolyte contains V(III)/V(IV) sulfate solution mixing electrolyte system, sulfonated graphene electrode/manganese dioxide/poly (3,4-ethylene dioxythiophene)-polystyrene sulfonate-phase composite electrode.