Preparation of High Softening Point Pitch and Its Application in Lithium Ion Battery

High softening point pitch is prepared using ethylene tar by air oxidation method, meanwhile, its application as coating pitch for graphite anode of lithium ion battery is also investigated. Combining with elemental analysis, TOF MS, GC-MS, FT-IR, TG, ¹H-NMR, the structure and characteristics of original ethylene tar and final pitch products were analyzed in detail. Also, the effusion gas and liquid during reaction process were studied. The results indicated that the softening point, carbon content and carbonization carbon yield increased with the oxidation reaction time. Such pitches contain various complex polycyclic aromatic hydrocarbon. The best pitch for coating one was obtained at the oxidation condition of 330 ℃, 9.5 h. The pitch with softening point of 216.9 ℃, has carbon content of 93.160% (mass fraction), its carbon yield of 51.4% when carbonized at 800 ℃. Comparing with the original graphite anode, after coating the pitch, the capacity increased by 26.3% at a current density of 100 mA/g and the cycling stability was greatly improved.