發(fā)布時(shí)間：2018-11-01 15:57

【摘要】：隨著人類工業(yè)化進(jìn)程的發(fā)展,傳統(tǒng)化石能源的大量開采,環(huán)境污染和能源危機(jī)已經(jīng)威脅到人類的健康和生存。因此,人類要實(shí)現(xiàn)可持續(xù)發(fā)展,追求綠色環(huán)保的生活方式,必須尋求和開發(fā)新能源,而發(fā)展二次電池被認(rèn)為是解決問題的方法之一。然而,鋰離子電池的進(jìn)一步應(yīng)用面臨資源短缺和價(jià)格昂貴的問題。最近鈉離子電池由于價(jià)格低廉,資源豐富吸引了大家的關(guān)注。總之,低價(jià),長循環(huán)壽命,室溫條件的鈉離子電池在未來大規(guī)模儲能系統(tǒng)中應(yīng)用很有前景。因此,本文主要討論了鈉離子電池的負(fù)極材料-熱解硬碳。(1)本文通過靜電紡絲技術(shù)制備的聚氯乙烯納米纖維作為前驅(qū)物,經(jīng)過600-800℃熱解獲得的硬碳樣品,與商業(yè)化的聚氯乙烯顆粒作為前驅(qū)物經(jīng)過熱解制備硬碳材料進(jìn)行對比。在室溫條件下,所獲得的硬碳樣品作為鈉離子電池負(fù)極材料進(jìn)行比較。通過700℃熱解聚氯乙烯納米纖維前驅(qū)物獲得硬碳,其首周可逆容量為271mAh/g,首周庫倫效率為70%;而通過熱解商業(yè)化聚氯乙烯顆粒獲得硬碳,其首周可逆容量僅為206mAh/g,首周庫倫效率為60%。此外,通過熱解聚氯乙烯納米纖維前驅(qū)物獲得硬碳具有良好的循環(huán)性能與倍率性能。其首周放電容量分別為389,228,194,178,147mAh/g電流密度分別為12,24,60,120與240 mA/g;其循環(huán)150周后仍然獲得211mAh/g的可逆容量。良好的循環(huán)性能,較高的可逆容量,優(yōu)異的倍率性能使此種硬碳可以成為很有競爭力的鈉離子負(fù)極材料。(2)本文同時(shí)也比較了兩組前驅(qū)物為同分異構(gòu)體獲得的硬碳材料:葡萄糖與果糖,麥芽糖與蔗糖,之后熱解制備為硬碳。通過熱重測試分析得到熱解溫度,通過掃描電鏡表征了熱解硬碳的形貌,之后通過充放電曲線測試,循環(huán)測試,倍率性能測試討論了所獲得樣品材料的電化學(xué)性能。最后得到葡萄糖,果糖,麥芽糖,蔗糖各自發(fā)現(xiàn)了最優(yōu)熱解溫度,分別是1000℃,1000℃,1000℃,1100℃;并且作為同分異構(gòu)體對比,發(fā)現(xiàn)葡萄糖各種電化學(xué)性能優(yōu)于果糖,而對于麥芽糖與蔗糖,在小電流密度下,麥芽糖性能優(yōu)異,然而倍率性能方面卻是蔗糖的好。因此,在選擇碳源時(shí)可以優(yōu)先考慮同其分異構(gòu)體。
[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，

本文編號：2304398