▎ 摘　　要

NOVELTY - Preparation of carbon-coated sandwich structure of tin selenide/reduced-graphene oxide-carbon composite adding graphene oxide to ethylene glycol or glycerol, dispersing, adding inorganic tin salt, stirring, adding surface active agent to dissolve to obtain first solution, adding selenium powder to reducing solvent, stirring to dissolve to obtain second solution, dripping second solution to first solution, to form third solution, hydrothermally reacting third solution, cooling to obtain fourth black solution, adding graphene oxide to ethylene glycol or glycerol, dispersing to obtain fifth solution, adding fifth solution to fourth solution, to obtain sixth solution, hydrothermally reacting sixth solution, cooling to obtain seventh solution, filtering and collecting, freeze-drying obtained black powder to obtain product, mixing the product and organic 2-methylimidazole solid phase, grinding, hydrothermally reacting obtained mixture, cooling, and thermally treating obtained black powder. USE - Preparation of carbon-coated sandwich structure of tin selenide/reduced-graphene oxide-carbon composite used for preparing negative electrode material for sodium ion battery (all claimed). ADVANTAGE - The method enables to prepare carbon-coated sandwich structure of tin sulfide/reduced-graphene oxide composite having high repeatability, improved conductivity and structure stability, and excellent electrochemical performance, in simple manner. DETAILED DESCRIPTION - Preparation of carbon-coated sandwich structure of tin selenide/reduced-graphene oxide-carbon composite adding 30-90 mg graphene oxide to 30-70 ml ethylene glycol or glycerol, dispersing, adding 0.0569-0.0569 g inorganic tin salt, stirring, adding 0.02-0.2 g surface active agent to completely dissolve to obtain first solution, adding 0.01975-1.975 g selenium powder to 3-10 ml reducing solvent, stirring to completely dissolve to obtain second solution, dripping second solution to first solution, stirring to form third solution, where the molar ratio of tin ion and selenium ion in third solution is 1:(1-4), hydrothermally reacting third solution at 120-200 degrees C, cooling to obtain fourth black solution, adding 10-30 g graphene oxide to 10-20 ml ethylene glycol or glycerol, dispersing to obtain fifth solution, adding fifth solution to fourth solution, stirring to obtain sixth solution, hydrothermally reacting sixth solution at 120-200 degrees C, cooling to obtain seventh black solution, filtering and collecting to obtain black powder, freeze-drying black powder to obtain product, mixing the product and organic 2-methylimidazole solid phase, grinding to obtain mixture, hydrothermally reacting the mixture at 160-240 degrees C and cooling to obtain black powder, and thermally treating black powder. INDEPENDENT CLAIMS are included for the following: (1) carbon-coated sandwich structure of tin selenide/reduced-graphene oxide-carbon composite; and (2) application of carbon-coated sandwich structure of tin selenide/reduced-graphene oxide-carbon composite, which involves mixing the composite with a binder and a conductive agent to prepare negative electrode material for sodium ion battery.