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題名 | 煤焦瀝青披覆天然石墨之鋰離子電池負極材料電化學影響研究=Electrochemical Effects on Coal Tar Pitch Coated Natural Graphite as Anode Materials of Lithium Ion Batteries |
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作者 | 吳玉祥; 黃家維; | 書刊名 | 中華科技大學學報 |
卷期 | 51 2012.04[民101.04] |
頁次 | 頁33-45 |
分類號 | 468.1 |
關鍵詞 | 天然石墨; 煤焦瀝青; 鋰離子電池; 負極材料; Natural graphite; Coal tar pitch; Lithium-ion battery; Anode material; |
語文 | 中文(Chinese) |
中文摘要 | 本研究使用表面改質的方式,將不同比例之煤焦瀝青(Coal tar pitch),披覆於天然石墨表面,形成一層非晶質碳材。天然石墨表面披覆煤焦瀝青,使BET變小,減少SEI膜的形成,進而降低第一次不可逆性,並增進循環性能,達到改善天然石墨電化學性能的目的。實驗中以X射線繞射儀(XRD)和掃描式電子顯微鏡(SEM)分析碳披覆石墨的結晶構造與表面型態,以BET法檢測粉末之比表面積,並利用真密度計測量密度,使用循環充放電測試儀探討電池之電化學特性,且以其結果探討披覆碳材料之不同對電化學特性之影響。於披覆不同添加量之煤焦瀝青中,其電性結果顯示天然石墨披覆15 wt.%之煤焦瀝青,第一次放電電容量為350 mAh/g,第一次不可逆性從原始之12.7%降低至6.9%,充放電循環於50次後,仍有優異的344 mAh/g之放電電容量。因此天然石墨披覆15 wt.%的煤焦瀝青,能有效改善天然石墨之第一次不可逆性及循環穩定性,擁有最佳電化學性能。 |
英文摘要 | In this study, coal tar pitch were prepared in different in different ratios and coated on surface of natural graphite to form a layer of amorphous carbon firm. The process of modification was able to decrease value of BET and the first irreversible capacity, reduce formation of SEI firm, and increase recycling ability that enhanced electrochemical property of natural graphite. The crystal structure and surface morphology of pitch coated graphite was analyzed by XRD and SEM. Surface area of powder was obtained by BET measurement and density was measured by pycnometer. The result of charge-discharge cycling tests revealed that electrochemical performance varied with different compositions of carbon material coated on graphite. The optimum result appeared on the sample coated by 15 wt.% of coal tar pitch, that the value of the first discharge capacity showed 350 mAh/g, the first irreversibility decreased from 12.7% to 6.9%, and the discharge capacity was 344 mAh/g after 50 cycles. In summary, the natural graphite coated by 15 wt.% of coal tar pitch had better features in first irreversible capacity and recycling stability, and its electrochemical performance was directly related to the composition of coal tar pitch. |
本系統之摘要資訊系依該期刊論文摘要之資訊為主。