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机构地区:[1]新疆大学能源材料化学教育部重点实验室先进功能材料新疆维吾尔自治区重点实验室应用化学研究所,乌鲁木齐830046
出 处:《无机材料学报》2017年第9期909-915,共7页Journal of Inorganic Materials
基 金:国家自然科学基金(U1203292);中国科学院西部之光人才培养计划(YBXM-2014-07)~~
摘 要:因具有较短的锂离子扩散路径、大的比表面积等优势,球形碳材料在锂离子电池负极材料中展露出良好的应用前景。研究以新疆库车产煤为原料,采用电弧放电法及化学活化法制备出了具有多孔结构的煤基球形碳。通过X射线衍射(XRD)、扫描电镜(SEM)、拉曼光谱(Raman)、氮气吸脱附法和恒电流充放电等测试手段对材料结构、形貌和电化学性能进行了表征。结果表明,在100 m A/g的电流密度下,煤基球形多孔碳的首次放电比容量可达到1188.9 mAh/g,远高于商业石墨负极372 mAh/g的理论比容量。此外,该材料还表现出了良好的循环稳定性,经历200圈循环后的放电比容量为844.9 mAh/g。煤基球形多孔碳优异的电化学性能得益于活化过程所产生的分级孔道结构能为锂离子提供更多储存空间,从而提高了电极的容量及循环稳定性。Spherical porous carbon nanomaterials is a promising candidate as anode materials for next-generation LIBs due to its large specific surface area which decreases the lithium ion transport distance. Spherical porous carbon nanomaterials with uniform morphology were prepared by arc-discharging followed by chemical activation using coal as precursor. The as-prepared spherical porous carbon samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), Raman spectrope (Raman), the nitrogen adsorption-desorption, galvanostatic charge and discharge method and so on. The result indicated that the spherical porous carbon materials have high specific capacity of 1188.9 mAh/g, which exceeds the commercial mesophase carbon spheres (372 mAh/g). Moreover, the spherical porous carbon nanomaterials also afford excellent cyclic stability and a reversible capacity of 844.9 mAh/g remains ever after 200 charge/discharge cycles at current density of 100 mA/g. The excellent electrochemical performance of coal based spherical porous carbon may be originated from the graded pore structure, which can provide more storage space for lithium ion, thus improving the capacity and cycle stability of the electrode.
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