热处理对针状焦电化学性能的影响

INFLUENCES OF HEAT-TREATMENT ON ELECTROCHEMICAL PERFORMANCE OF NEEDLE COKE

利用X射线衍射(XRD)、扫描电子显微镜(SEM)和恒流充放电方法对不同热处理温度下针状焦的微观物理结构和充放电循环性能进行了研究。结果表明,随着热处理温度的升高,针状焦石墨化程度增加,微观晶体结构趋于完整,表面缺陷减少,800℃下热处理样品初次嵌锂容量达到463mA·h/g;随着热处理温度的升高,材料的循环稳定性显著提高,2800℃石墨化处理样品50次循环后可逆容量可达360mA·h/g。

Needle cokes heat-treated at different temperatures were investigated by means of X-ray diffraction spectra （XRD）, scanning electron microscope （SEM） and galvanostatic discharge/charge cycle tests. It was found that the degree of graphitization and the crystallite size increased with the temperature of heat-treatment, leading to quite flat morphology. Electrochemical tests demonstrated that needle coke heat-treated at 800 ℃ exhibits an initial capacity of 463 mA· h/g. After graphitization at 2 800 ℃ , the cycle performance was further improved and a reversible capacity of 360 mA· h/g was obtained after 50 cycles.