钠离子电池热解硬碳负极材料的合成与电化学性能研究

发布时间：2018-11-01 15:57

【摘要】：随着人类工业化进程的发展,传统化石能源的大量开采,环境污染和能源危机已经威胁到人类的健康和生存。因此,人类要实现可持续发展,追求绿色环保的生活方式,必须寻求和开发新能源,而发展二次电池被认为是解决问题的方法之一。然而,锂离子电池的进一步应用面临资源短缺和价格昂贵的问题。最近钠离子电池由于价格低廉,资源丰富吸引了大家的关注。总之,低价,长循环寿命,室温条件的钠离子电池在未来大规模储能系统中应用很有前景。因此,本文主要讨论了钠离子电池的负极材料-热解硬碳。(1)本文通过静电纺丝技术制备的聚氯乙烯纳米纤维作为前驱物,经过600-800℃热解获得的硬碳样品,与商业化的聚氯乙烯颗粒作为前驱物经过热解制备硬碳材料进行对比。在室温条件下,所获得的硬碳样品作为钠离子电池负极材料进行比较。通过700℃热解聚氯乙烯纳米纤维前驱物获得硬碳,其首周可逆容量为271mAh/g,首周库伦效率为70%;而通过热解商业化聚氯乙烯颗粒获得硬碳,其首周可逆容量仅为206mAh/g,首周库伦效率为60%。此外,通过热解聚氯乙烯纳米纤维前驱物获得硬碳具有良好的循环性能与倍率性能。其首周放电容量分别为389,228,194,178,147mAh/g电流密度分别为12,24,60,120与240 mA/g;其循环150周后仍然获得211mAh/g的可逆容量。良好的循环性能,较高的可逆容量,优异的倍率性能使此种硬碳可以成为很有竞争力的钠离子负极材料。(2)本文同时也比较了两组前驱物为同分异构体获得的硬碳材料:葡萄糖与果糖,麦芽糖与蔗糖,之后热解制备为硬碳。通过热重测试分析得到热解温度,通过扫描电镜表征了热解硬碳的形貌,之后通过充放电曲线测试,循环测试,倍率性能测试讨论了所获得样品材料的电化学性能。最后得到葡萄糖,果糖,麦芽糖,蔗糖各自发现了最优热解温度,分别是1000℃,1000℃,1000℃,1100℃;并且作为同分异构体对比,发现葡萄糖各种电化学性能优于果糖,而对于麦芽糖与蔗糖,在小电流密度下,麦芽糖性能优异,然而倍率性能方面却是蔗糖的好。因此,在选择碳源时可以优先考虑同其分异构体。
[Abstract]:With the development of human industrialization and the exploitation of traditional fossil energy, environmental pollution and energy crisis have threatened the health and survival of human beings. Therefore, in order to achieve sustainable development and to pursue a green lifestyle, we must seek and develop new energy sources, and the development of secondary batteries is considered to be one of the solutions to the problem. However, the further application of lithium ion batteries faces the problems of shortage of resources and high price. Recently, sodium ion batteries have attracted much attention because of their low price and abundant resources. In a word, sodium ion batteries with low cost, long cycle life and room temperature can be used in large scale energy storage systems in the future. Therefore, this paper mainly discusses the negative electrode material of sodium ion battery-pyrolytic hard carbon. (1) the hard carbon samples obtained by pyrolysis at 600-800 鈩，

本文编号：2304398