The invention provides a method for preparing a
sodium-storage hard carbon negative
electrode material from heavy oil, which comprises the following steps: by taking the heavy oil as a
raw material,
doping 1wt%-5wt% of an acidic catalyst and an
aldehyde crosslinking agent, and putting the mixture into a
corrosion-resistant reaction kettle for shallow crosslinking polycondensation treatment; then carrying out air oxidation crosslinking to obtain an isotropic
asphalt product with good fluidity and low
quinoline insoluble content; and carrying out
carbonization and acid-base
etching treatment to prepare the
sodium-storage hard carbon negative
electrode material with excellent rate capability and long-period stability. According to the method, the
utilization rate of small molecules in the
ethylene tar is guaranteed through shallow cross-linking polycondensation by adding the acid catalyst and the
aldehyde cross-linking agent, and the yield of the material is remarkably improved; and treating a cross-linked polycondensation product by using an oxidation cross-linking process to prepare the high-carbon-residue isotropic
asphalt with different
softening points and low
quinoline insoluble content. On the basis of the process, a
carbonization-acid-alkali
etching process is utilized to treat isotropic
asphalt, and the
sodium storage hard carbon negative
electrode material with high
battery capacity, excellent rate capability and long-period stability is prepared.