▎ 摘　　要

NOVELTY - Double-layer graphene tube comprises outerlayer tube and inner layer tube, where inner layer tube is doped with nitrogen element, and the distance between the outer layer tube and the inner layer tube is 5-20 nanometer. USE - Double-layer graphene tube. ADVANTAGE - The double-layer graphene tube inhibits non-carbon active material in negative electrode material during the charging/discharging process, ensures fast ion and electron conduction channel in the electrode reaction process, and improves the quality of lithium battery specific capacity and volume capacity. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) a method for preparing double-layer graphene tube, which involves mixing magnesium salt solution and the urea solution to obtain mixed solution; mixing the mixed solution in a hydrothermal kettle for hydro-thermal reaction, then filtering, drying and calcining to obtain magnesium oxide template; adding magnesium oxide template in the high temperature reactor, continuously heating up, introducing the first gas, introducing the second gas into the high temperature reactor; dispersing reaction product obtained in the mixed solution containing the magnesium salt solution and the urea solution, and then reacting at a second predetermined temperature; adding reaction product obtained in the high temperature reactor to continuously heating, introducing the first gas, reaching to third predetermined temperature, introducing the third gas into the high temperature reactor; and mixing reaction product with the liquid obtained, and drying to obtain double-layer graphene tube; (2) a negative electrode material, which comprises a double-walled graphene, double-layer graphene tube; non-carbon material precursor which is loaded between the outer layer pipe of the double-layer graphene tube and an inner layer tube; (3) a method for preparing negative electrode material, which involves mixing double-layer graphene pipe, non-carbon material precursor and water to obtain the mixed liquid; mixing the mixed dispersion in the hydrothermal kettle for hydro-thermal reaction, adding reaction product obtained in the high temperature reactor, and introducing gas to obtain negative electrode material; (4) a lithium battery, which has the negative electrode material; and (5) a automobile, which comprises lithium battery.