- 學位論文
馬來醯亞胺添加劑結構對於鋰離子電池性能影響之研究
Structural Study of Maleimide-based Additives for Lithium Ion Batteries
摘要
本實驗中，我們將探討互為同分異構物(於苯環上的位置各別為鄰位、間位、對位)的馬來醯亞胺添加劑，其不同結構對於鋰離子電池中的鈍化層及其電池性能的影響。 我們使用循環伏安法發現此種添加劑的還原電位早於電池中其它電解液成分，接著使用核磁共振光譜再進一步發現馬來醯亞胺分子經過還原反應後的產物仍維持和苯環上的連接位置，且馬來醯亞胺本身的碳碳雙鍵經過還原之後仍存在，而本研究也提出其可能的產物結構。在交流阻抗分析中發現，立體障礙會影響鈍化層介面阻抗大小。由X光光電子光譜(XPS)發現鈍化層內部的無機成分中的氟化鋰(LiF)含量在加入馬來醯亞胺添加劑之後可以有效減少。 最後，在電池性能表現中，添加劑在後續1C/1C電流的100圈循環充電中，測試初期添加劑結構上的差異性主要表現在放電電容量上的損失。隨著圈數增加，其含有添加劑的電池之放電電容量趨於穩定不再減少。其中，原先分子立體障礙較大的添加劑表現更勝過無添加劑者。
並列摘要
In this study, we chose maleimide-based additives which are isomer for each other (the maleimide substituent on the benzene are para-, meta-, and ortho- position) to investigate the structural effect in SEI and the battery performance. First, the cyclic voltammetry (CV) measurement showed that the reduction potential of maleimide-based additive was prior to other components. Then, the structure of maleimide product was further found retaining the same connected sites to benzene and keeping C=C configuration after reduction based on the results of nuclear magnetic resonance (NMR). The possible product structure for different maleimide-based additive was proposed in this study. In the analysis of impedance spectra, the resistance of SEI was influenced by steric hindrance of the additive. The X-ray photoelectron spectroscopy (XPS) demonstrated the content of a specific inorganic compound, LiF, was decreased due to the existence of maleimide-based additive in the electrolyte. Finally, in the battery performance test, the structural effect of additive showed remarkable divergence in discharge capacity loss in the initial 1C/1C cycle test. As the cycle proceeded, the discharge capacity of batteries with maleimide additives reached a steady state and did not reduce anymore. Besides, the performance of the additive with large steric hindrance even excelled the one without any additive.