Effect of Asphalt Granulation on the Performance of Artificial Graphite Anode Materials for Lithium-Ion Batteries

In order to investigate the effects of the softening point, the addition ratio, and the median particle size (D_v50) of the asphalt on the performance of secondary particles of artificial graphite anode materials prepared by granulation, ten-kilogram orthogonal experiments were designed. D_v50 and powder orientation index (OI) value of the prepared secondary particles of artificial graphite anode materials were employed as evaluation index, and the results of the orthogonal experiments were subjected to polarity analysis, analysis of variance (ANOVA), and multiple linear regression analysis. It is demonstrated that the addition ratio of the asphalt exerts the most pronounced influence on D_v50 and powder OI value of secondary granular artificial graphite anode materials, followed by the softening point. Conversely, the median particle size D_v50 of the asphalt exerts the least significant effect. With regard to the evaluation indices, the optimal granulation conditions were determined to be a softening point of 250 °C, an addition ratio of 11%, and D_v50 of 2-3 μm of the asphalt. D_v50 of the prepared secondary granular artificial graphite anode material was 17.91 μm, with an OI value of 1.91. The specific capacity of the first charging was 340.52 mAh/g, and the first columbic efficiency was 94.79%.