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利用PVA碳源包覆、HF酸刻蚀和沥青二次包覆方法制备多孔珊瑚状硅/碳复合负极材料,得到沥青含量分别为30%、40%和50%(质量分数)的3种硅/碳复合材料样品。采用XRD和SEM分别对复合材料的组成和形貌进行表征,并采用电化学测试手段对其性能进行测试。结果表明,经二次沥青包覆后,复合材料的电化学性能得到明显提高。当二次包覆的沥青含量为40%时,在100 m A/g的电流密度下,该样品第二次充放电循环的放电容量达到773 m A·h/g,经60次循环后,放电容量仍然保持在669 m A·h/g,其容量损失率仅为0.23%/cycle。因此,调整二次包覆碳含量可明显改善复合材料的循环稳定性。
Porous Coral silicon / carbon composite negative electrode materials were prepared by coating with PVA carbon source, HF acid etching and secondary bitumen coating. Three kinds of silicon with 30%, 40% and 50% bitumen content were obtained respectively / Carbon composite samples. The composition and morphology of the composites were characterized by XRD and SEM, respectively, and their performances were tested by electrochemical test. The results show that after the secondary bitumen coating, the electrochemical performance of the composite material has been significantly improved. When the secondary coating content of bitumen is 40%, the discharge capacity of the second charge-discharge cycle reaches 773 mA · h / g at a current density of 100 m A / g. After 60 cycles, Discharge capacity remained at 669 mA · h / g, the capacity loss rate of only 0.23% / cycle. Therefore, adjusting the secondary coated carbon content can significantly improve the cycle stability of the composite material.