▎ 摘　　要

NOVELTY - Preparation of double-functional lithium-air battery composite diaphragm involves: (1) dissolving three kinds of transition metal nitrate hydrates in methanol, and magnetically stirring to obtain a solution (A), dissolving a nitrile group-containing imidazole in methanol, and stirring to obtain a solution (B), mixing the solutions (A) and (B), reacting, centrifuging, and collecting obtained precipitate, washing, and drying to obtain multi-metal synergetic catalytic metal-organic frameworks (MOFs); (2) preparing a super-hydrophobized multimetal synergistic catalytic MOFs using the obtained MOFs, p-methylbenzonitrile and N-acetyl-L-cysteine; (3) mixing the super-hydrophobized multimetal synergistic catalytic MOFs, binder and conductive agent to prepare a slurry, uniformly stirring, then adding an organic solvent, and fully stirring to obtain a coating slurry; and (4) uniformly coating the obtained coating slurry on a base film, and drying. USE - The method is useful for preparing double-functional lithium-air battery composite diaphragm. ADVANTAGE - The method provides double-functional lithium-air battery composite diaphragm, which has excellent wetting property, oxygen reduction reaction/oxygen evolution reaction catalytic properties and superhydrophobic properties, and water droplet contact angle of greater than 160°, reduces the polarization voltage of the lithium-air battery, improves cycle performance and safety performance of the lithium-air battery, and effectively prevents the moisture in the air from spreading to the lithium metal cathode to avoid the corrosion of cathode lithium sheet. DETAILED DESCRIPTION - Preparation of double-functional lithium air battery composite diaphragm involves: (1) dissolving three kinds of transition metal nitrate hydrates in methanol, and continuously and magnetically stirring at room temperature to obtain a solution (A), dissolving a nitrile group-containing imidazole in methanol, and stirring at room temperature to obtain a solution (B), mixing the solutions (A) and (B) together, fully reacting for 24-48 hours under the condition of continuously stirring, centrifuging, and collecting the obtained precipitate, fully washing the precipitate 4-6 times with methanol, and drying the washed precipitate in a vacuum oven at 70-80℃ for 12 hours to obtain multimetal synergetic catalytic metal-organic frameworks (MOFs); (2) dissolving the multimetal synergistic catalytic MOFs, p-methylbenzonitrile and N-acetyl-L-cysteine in methanol, gradually adding hydrazine hydrate under argon atmosphere, continuously stirring the obtained mixed solution at room temperature for 5-7 days, fully reacting to obtain a suspended substance, filtering, collecting the obtained suspended substance, washing 3-5 times with methanol, vacuum drying at 70℃ for 12 hours to obtain an intermediate product (A), dissolving in methanol, gradually adding 10-15% hydrogen peroxide solution, continuously stirring at room temperature for 24-30 hours, filtering, collecting the generated suspended solid, washing 3-5 times with methanol, drying at 70-80℃ for 12 hours to obtain an intermediate product (B), mixing with octadecene and diethyl ether to prepare a mixture, heating in an oil bath at 30℃, continuously stirring, fully reacting for 1.5-12 hours, collecting the obtained solid, washing 3-5 times with diethyl ether to obtain an intermediate product (C), soaking in diethyl ether, placing at room temperature for 2-5 hours, and drying in vacuum oven at 40℃ for 12 hours to obtain a super-hydrophobized multimetal synergistic catalytic MOFs; (3) mixing the super-hydrophobized multimetal synergistic catalytic MOFs, binder and conductive agent to prepare slurry, uniformly stirring in a stirrer, then adding an organic solvent, and fully stirring to obtain a coating slurry; and (4) uniformly coating the obtained coating slurry on a base film, and drying in a vacuum drying box at 50-60℃ for 8-12 hours. The mass ratio of transition metal nitrate hydrate (I), transition metal nitrate hydrate (II) and transition metal nitrate hydrate (III), and methanol is 1:1:1:(100-150). The mass ratio of nitrile group-containing imidazole and methanol is 1:(20-25). The mass ratio of multimetal synergistic catalytic MOFs, p-methylbenzonitrile, N-acetyl-L-cysteine, hydrazine hydrate and methanol is 1:(0.5-1.5):(1.5-2.5):(2-3):(40-70). The mass ratio of the intermediate product (A), hydrogen peroxide solution and methanol is 1:(15-25):0.5. The mass ratio of the intermediate product (B), octadecene and diethyl ether is (0.3-0.5):10:(15-20). The mass ratio of the intermediate product (C) and diethyl ether is 1:(10-20). The mass ratio of super-hydrophobized multimetal synergistic catalytic MOFs, binder, conductive agent and organic solvent is (1-3):(0.5-1):1:(4-5).