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標題: | 透過交聯磺酸化幾丁聚醣作為負極保護層以改善鋰離子電池之效能 Improving Anode Performance via Crosslinking Sulfonated Chitosan Protective Coating in Lithium Ion Batteries |
作者: | Chia-Yang Lu 呂家揚 |
指導教授: | 趙基揚 |
關鍵字: | 鋰離子電池,磺酸化幾丁聚醣,保護層,石墨負極,矽碳負極, Lithium-ion battery,Crosslinking sulfonated chitosan,Protective layer,Graphite,Silicon/graphite composite anode, |
出版年 : | 2019 |
學位: | 碩士 |
摘要: | 在鋰離子電池的操作期間,液體電解質將與活性電極材料反應,導致電解液的消耗和非導電固態電解質介面(SEI)的增厚,從而使電容量與庫倫效率在高充放電速率下逐漸衰減。在活性電極材料上構建鋰離子傳導保護層是一個有效的策略來抑制電解液分解和不好的SEI生成,同時還可以保持電極的良好電化學性能,從而提高循環穩定性和高充放電速率性能。
本研究中,我們成功開發了一種高機械強度的高分子應用於負極材料保護層,由交聯磺酸化幾丁聚醣(X-SCS)披覆在天然石墨(NG)和矽/碳複合材料(Si@G)表面,以達到抑制電解液的分解、適應電極體積的變化及電極性能的提升。透過系統性地調控X-SCS塗層的交聯程度來優化電極性能。研究結果發現,X-SCS塗覆的NG負極在電化學性能得到顯著改善,同時提升庫侖效率、充放電速率能力和循環穩定性。同時,X-SCS塗覆的Si@G電極中,在無FEC電解液環境下,經過50次充放電循環可以表現出超過95%的容量保持率;若在含FEC的電解液環境下,經過100次充放電循環展現出93.5%的容量保持率。因此,構建具有高機械強度的鋰離子傳導保護層是一種提升Si@G負極性能和循環穩定性的有效方法。 During the operation in a lithium-ion battery (LIB), liquid electrolytes (LE) would react with the active electrode materials, leading to consumption of LE and thickening of non-conductive solid electrolyte interphase (SEI) layer, and thus resulting in gradual decay in capacity and lowered efficiency at high C-rate. Constructing a lithium-ion conductive protective layer on the active electrode materials is an appraisable strategy to suppress the decomposition of LE and the undesirable SEI formation while to retain good electrochemical performance of the electrodes; and thus to improve the long term stability and high C-rate performance. In this work, we successfully develop a mechanically robust polymeric protective layer made from crosslinking sulfonated chitosan (X-SCS) on natural graphite (NG) particles and silicon/graphite (Si@G) composites in the anode to concurrently inhibit LE decomposition, accommodate electrode volume changes and promote electrode performance. The amount and the degree of crosslinking of the X-SCS coating are systematically varied to optimize the electrode performance. With X-SCS coating, the electrochemical properties of the NG anode, including Coulombic efficiency, rate capability and cycling stability are significantly enhanced. Meanwhile, the X-SCS-coated Si@G electrodes exhibit over 95% capacity retention after 50 cycles with a FEC-free electrolyte and 93.5 % capacity retention after 100 cycles using a FEC-containing electrolyte. Hence, building a lithium-ion conductive protective layer with high mechanical strength could be an appraisable approach to promote the Si@G anode performance and cycling stability. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/72619 |
DOI: | 10.6342/NTU201900710 |
全文授權: | 有償授權 |
顯示於系所單位: | 材料科學與工程學系 |
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