▎ 摘　　要

NOVELTY - Preparing nitrogen-doped carbon/molybdenum selenide/graphene nanobox material, comprises e.g. (i) stirring the iron(III) chloride solution, adding sodium hydroxide solution under continuous stirring, and reacting to obtain iron(III) hydroxide gel and placing iron(III) hydroxide gel in an oven to obtain red product iron(III) oxide nanoparticles and washing, drying to obtain iron(III) oxide nanoparticles, (ii) dispersing the iron(III) oxide nanoparticles template uniformly in trisaminomethane buffer solution, ultrasonically dispersing, then adding dopamine hydrochloride, stirring, collecting the iron(III) oxide-phenylenediamine product obtained by centrifugation and washing the iron(III) oxide-phenylenediamine product with deionized water and ethanol, drying overnight in an oven to obtain iron(III) oxide-polydopamine core-shell nanoparticles, and (iii) calcining the iron(III) oxide-polydopamine core-shell nanoparticles in an inert atmosphere. USE - The nitrogen-doped carbon/molybdenum selenide/graphene nanobox material is useful as cathode material for sodium ion battery (claimed). ADVANTAGE - The nitrogen-doped carbon/molybdenum selenide/graphene nanobox material has excellent conductivity and porous structure, which is conducive to electron transport and electrolyte penetration; reduces the dissolution damage of molybdenum selenide; improves the stability and rate performance of the material; and solves the technical problems of serious self-polymerization, weak conductivity, large volume deformation, and low capacity of pure molybdenum selenide as a cathode material for sodium ion batteries. DETAILED DESCRIPTION - Preparing nitrogen-doped carbon/molybdenum selenide/graphene nanobox material, comprises (i) stirring the iron(III) chloride solution at 50-75 degrees C for 5-10 minutes, slowly adding sodium hydroxide solution within 5-10 minutes under continuous stirring, and reacting at the same temperature for 5-20 minutes to obtain iron(III) hydroxide gel and placing iron(III) hydroxide gel in an oven at 80-120 degrees C for 3-5 days to obtain red product iron(III) oxide nanoparticles and then washing obtained red product iron(III) oxide nanoparticles many times with deionized water and ethanol, and then drying in an oven overnight to obtain iron(III) oxide nanoparticles, (ii) dispersing the iron(III) oxide nanoparticles template uniformly in trisaminomethane buffer solution and ultrasonically dispersing for 10-20 minutes, then adding dopamine hydrochloride and stirring for 1-4 hours, collecting the iron(III) oxide-phenylenediamine product obtained by centrifugation, and washing the iron(III) oxide-phenylenediamine product with deionized water and ethanol many times, then dry overnight in an oven to obtain iron(III) oxide-polydopamine core-shell nanoparticles, (iii) calcining the iron(III) oxide-polydopamine core-shell nanoparticles in step (ii) in an inert atmosphere at 500-700 degrees C for 2-4 hours, and then dispersing the resulting product in a dilute acid solution and stir for 12-24 hours to completely remove the template, and then collecting the resulting product by centrifugation, washing many times with ethanol and drying, calcining in an inert atmosphere at 600-800 degrees C for 1-3 hours to obtain nitrogen-doped carbon nano-box, (iv) adding the selenium powder into hydrazine hydrate and then stirring to obtain deep red mass concentration of 2-8 mg.ml-1 selenium-hydrazine solution to obtain selenium-hydrazine solution, (v) disperse the nitrogen-doped carbon (NC) nanobox in a mixed solution of N,N-dimethylformamide and deionized water (volume ratio 3:1) for ultrasonic dispersion, slowly dripping the prepared selenium-hydrazine solution into the suspension containing nitrogen-doped carbon (NC) under magnetic stirring, then adding sodium molybdate, transfer the obtained homogeneous mixture to an autoclave for reaction at 180-220 degrees C for 12-24 hours, cooling, separating the product by high speed centrifugal, washing using de-ionized water for many times, then calcining the obtained black product at 400-500 degrees C for 1-3 hours to improve its crystallinity i.e. nitrogen-doped carbon (NC)/ molybdenum selenide nano-box, (v) dissolving the nitrogen-doped carbon (NC)/molybdenum selenide nano-box prepared in step (v) in water, adding surfactant and graphene oxide solution successively, heating at 80-120 degrees C, adding reducing agent and reacting for 4-8 hours, washing and drying the intermediate product, placing into high temperature tubular furnace for calcining for 1-3 hours under the inert atmosphere 400-500 degrees C, then calcining for 1-3 hours under the condition of 700-800 degrees C to obtain nitrogen-doped carbon/molybdenum selenide/graphene nano-box material. An INDEPENDENT CLAIM is also included for nitrogen-doped carbon/molybdenum selenide/graphene nanobox material obtained by above method, the nitrogen-doped carbon/molybdenum selenide/graphene nanobox material has a sandwich structure, the sandwich structure is composed of a nitrogen-doped carbon nanobox used as a substrate, a molybdenum selenide layer grown on the substrate, and a graphene layer on the molybdenum selenide layer.