▎ 摘　　要

NOVELTY - Method for preparing nanocomposite film containing europium ion nanocellulose/modified graphene oxide by (i) dissolving 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO) and sodium bromide, adding natural cellulose and sodium hypochlorite, filtering, washing, drying, and finally re-dispersing in deionized water to form nanocellulose dispersion, (ii) dispersing graphene (GO) in anhydrous dimethylacetamide (DMAc), adding hexamethylene 1,6-hexaisocyanate (HMDI) and stirring at 100-120 degrees C to obtain graphene oxide solution, (iii) mixing the nanocellulose dispersion with the HMDI modified graphene oxide solution, stirring and ultrasonically mixing the mixed dispersion to prepare a TEMPO-oxidized cellulose nanofibers (TOCN)/modified graphene oxide nano dispersion, and (iv) casting the TOCN/modified graphene oxide nano dispersion into a film, drying, immersing in europium(III) nitrate solution to form hydrogel film, washing and air-drying to obtain the film. USE - The nanocomposite film is used in dielectric energy storage. ADVANTAGE - The method has low dielectric loss, high dielectric constant, breakdown field strength and energy storage density, and has broad and extremely potential application prospects. DETAILED DESCRIPTION - Method for preparing nanocomposite film containing europium ion nanocellulose/modified graphene oxide by (i) dissolving 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO) and sodium bromide, adding natural cellulose and sodium hypochlorite, adjusting the pH of the system to 9-11 at 10-30 degrees C by low oxidation reaction for 0.5-7 hours, filtering, washing, drying, and finally re-dispersing in deionized water to form nanocellulose dispersion, (ii) dispersing graphene (GO) in anhydrous dimethylacetamide (DMAc), adding hexamethylene 1,6-hexaisocyanate (HMDI) and stirring at 100-120 degrees C to obtain graphene oxide solution, (iii) mixing the nanocellulose dispersion with the HMDI modified graphene oxide solution, stirring and ultrasonically mixing the mixed dispersion to prepare a TEMPO-oxidized cellulose nanofibers (TOCN)/modified graphene oxide nano dispersion, and (iv) casting the TOCN/modified graphene oxide nano dispersion into a film, drying, immersing the film in europium(III) nitrate solution to form hydrogel film, washing and air-drying to obtain the film.