▎ 摘　　要

NOVELTY - Preparing lanthanum-based oxide composite nano material, comprises (i) adding lanthanum(III) nitrate hexahydrate, nitrate and graphene oxide into N,N-dimethylformamide, and mixing and stirring for 2 hours, (ii) adding polyvinylpyrrolidone K-30 under low-speed magnetic stirring condition, mixing uniformly, stirring and heating the solution to boil, reducing the heating temperature when the solution evaporates to 1/3 of the original solution volume, and continuously stirring until the solution becomes colloid, and (iii) transferring the product prepared in step (ii) into a quartz boat, then placing in a muffle furnace for high-temperature calcining, reacting completely, taking out, grinding into powder, and freeze-drying to obtain final product. USE - The lanthanum-based oxide composite nano material is useful for electrochemical energy storage devices, preferably supercapacitor (claimed). ADVANTAGE - The method: has simple process and low cost; and is suitable for industrial production.