威宁无烟煤基石墨制备及其电化学性能研究

Preparation and electrochemical properties of Weining anthracite-based graphite

以贵州威宁无烟煤为原料,通过物理提纯可制备低灰(1.60%)无烟煤,探究了不同石墨化温度对无烟煤基石墨微观结构的影响,并进一步考察了威宁无烟煤石墨化样品用作锂离子电池负极材料的电化学性能。研究表明:随热处理终温的升高,煤基石墨样品石墨化度和石墨晶体结构有序度逐渐提高,在2800℃下所得煤基石墨石墨化度可达96.99%。煤基石墨的首次可逆容量和库伦效率随石墨化终温升高而逐渐提高,煤基石墨WN-2800在0.1C(1C=372 mAh/g)电流密度下首次可逆容量和库伦效率分别可达293.5 mAh/g、86.8%。煤基石墨WN-2800在1C电流密度下经过100次循环后,可逆容量为241.0 mAh/g,且库伦效率始终接近100%。煤基石墨WN-2800表现出较优异的综合电化学性能。本研究表明,威宁无烟煤可作为制备高性能煤基人造石墨的优质原料。

The anthracite with low ash content of 1.60%from Guizhou Weining was prepared by physical purification.The effect of dif-ferent graphitization temperatures on the microstructure of anthracite-based graphite was investigated,and the electrochemical perform-ance of the graphitized samples of Weining anthracite as negative electrode materials for lithium-ion batteries was further evaluated.The results show that with the increase of the final heat-treatment temperature,both the graphitization degree and the order degree of the graphite crystal gradually increase.The graphitization degree of the coal-based graphite obtained at 2800℃can reach 96.99%.The first reversible capacity and coulomb efficiency of coal-based graphite gradually increase with the increase of final graphitization tem-perature.The first reversible capacity and coulomb efficiency of coal-based graphite WN-2800 can reach 293.5 mAh/g and 86.8%re-spectively at 0.1C(1C=372 mAh/g).The reversible capacity of WN-2800 is 241.0 mAh/g after 100 cycles at 1C,and the coulomb ef-ficiency is always close to 100%.Coal-based graphite WN-2800 shows excellent comprehensive electrochemical performance.This study shows that Weining anthracite can be used as a high-quality raw material for the preparation of high-performance coal-based ar-tificial graphite.