- 學位論文
微波電漿改質鋰離子電池石墨烯負極材料之研究
Modification of Lithium ion Battery Graphene-based Anode Materials using Microwave Plasma
摘要
中文摘要 本研究使用氮氣/氫氣混合氣體於微波電漿反應系統進行電漿改質石墨烯，改變各種電漿操作參數(基材與共振腔之距離、電漿功率、氣體流量配比等)進行探討，以FE-SEM、FTIR-ATR、XPS、拉曼光譜儀、接觸角等儀器分析表面物理結構和化學元素組成分析之變化，並以OES分析電漿中物種變化之情形，再以電池充放電、交流阻抗、伏安循環分析其電化學性質，以瞭解電漿參數、膜材表面物化性質及電化學性質三者間相互之關係。 改變基材與共振腔距離使其於不同反應區(放電區、過渡區、後輝光區)，距離越近離子轟擊越強對於石墨烯結構填補效果提升，疏水性提升，使電解質產生的電阻降低，電池電容量提升。提升電漿功率使腔體內電子密度及溫度上升，氣體被解離的量變多，反應物種增加，使基材可在短時間內將石墨烯缺陷填補，會使得電池電容量增加。改變氮氣/氫氣相互間配比使得電漿內各活性物種含量不同，發現添加氫氣有助於氮氣解離，提升石墨烯結構填補效果，去氧能力上升，使疏水性提升。IR分析得知添加氫氣後含氮量上升，當氮氣/氫氣比例為2:1時，在0.1C的充放電速率下提供了1886 mAh/g的可逆電容量，為原始基材電容量約3倍之多。 本研究成功以微波氮氣/氫氣電漿將基材氮化並將石墨烯缺陷填補，應用於鋰離子電池負極，進而使電池電容量增加。
並列摘要
In this study, the graphene films were modified by N2/H2 gas mixture in a microwave plasma reactor. The surface analysis (FE-SEM, FTIR-ATR, XPS, Raman, CA), plasma diagnostics (OES) and the electrochemical analysis ( Galvanostatic charge/discharge, EIS, CV) were used to investigate the effect of operating parameters on the graphene. The results show that the substrate position inside the plasma reactor (Discharge zone, Transition zone, Afterglow zone) affects graphene structural integrity. The sample placed in discharge zone has a larger battery capacitance. Increasing input power would increase electron density and electron temperature, resulting in the generations of more reactive species. The result showed that the battery capacity increased with increasing power. Changing the nitrogen / hydrogen feed ratio would lead to the change of species composition in the plasma. We found that hydrogen addition would help in improving the integrity of the graphene structure. The largest charge capacitance generated up to 1886 mAh‧g-1 was found in samples treated in nitrogen/hydrogen plasma with a feed ratio of 2:1.