橄欖石結構LiFePO4是極具潛力的鋰離子電池陰極材料，其擁有諸多優勢：電池壽命長、對環境友善、成本較低及高溫穩定性佳等。然而較低的鋰離子遷移率及較差的導電度等二問題限制了它在儲能系統上的應用。
本實驗室回流法合成的薄片狀LiFePO4可縮短鋰離子進出所需遷移的路徑，提升其脫嵌的效率，研究的首要目的為放大製程並使產物維持薄片狀，若單次合成量較大，可用同次合成的產物進行多項實驗參數及製程的調整測試。論文中將針對鍛燒溫度、氧化石墨烯混雜及二茂鐵添加於氮氣流下進行熱處理，進行導電性提升的改質研究。
XRD及SEM分析得到，增量製程的產物為單一相之LiFePO4粉末，且具有與單倍合成相同之片狀形貌。以蔗糖碳源包覆碳膜，將鍛燒溫度由750℃提升至850℃，LiFePO4會有較高的結晶性，碳膜亦含有較多六元環結構，電池在0.1C下可表現接近理論之168.6 mAh/g比電容。此外，摻雜還原氧化石墨烯及添加二茂鐵均可使碳膜石墨化程度大幅提升，並反映在電池較小的極化電壓上。其中，混摻還原氧化石墨烯作為活性物質間的導電介質，可使電池在高C-rate下維持較高的比電容與工作電壓，有助於LiFePO4在高功率元件的應用。

Olivine-structured LiFePO4 is a promising cathode material for Li-ion batteries. It possesses many advantages, including longer battery life, environmental friendliness, relatively low cost and high temperature stability. However, the two major problems: low lithium ion diffusivity and poor electric conductivity retard its applications in energy storage systems.
The flake-like LiFePO4 synthesized with a reflux method developed by our laboratory can shorten the migration path of lithium ions, which could improve the efficiency of inter- and deintercalation. One purpose of this study is to increment the synthesized amount and keep its production a flake-like shape. If the yield of a single synthesis can be increased, the production of a batch can be used to test many experimental parameters and processes. In this thesis, we conducted a quality improvement study of the electric conductivity increase by graphene oxide hybridization, ferrocene addition and chaging the calcination temperature. The calcination of LiFePO4 were conducted under nitrogen flow.
XRD and SEM analysis showed that the synthesized single-phase LiFePO4 powders of the incremental process have the similar flake-like shape as the normal process. If we use sucrose as the carbon source and increase the calcination temperature from 750℃ to 850℃, LiFePO4 will have higher crystallinity. The carbon film also contains more hexatomic ring. The battery can deliver a specific capacity of 168.6 mAh/g, which is close to the theoretical value, at 0.1C. Adding reduced graphene oxide (rGO) and ferrocene can both significantly increase the graphitization degree of carbon films, which shown in the smaller polarization voltage of the battery. Mixing rGO as a conducting medium will let the battery maintaining a good specific capacity and working voltage at higher C-rate for high-power applications.

目錄 v
表目錄 viii
圖目錄 x
第一章 緒論 1
1.1 前言 1
1.2 研究動機與目的 2
第二章 文獻回顧 4
2.1 鋰離子電池介紹 4
2.2 鋰離子電池基本原理 7
2.3 負極材料 9
2.4 電解質 10
2.5 隔離膜 11
2.6 正極材料 12
2.7 橄欖石LiFePO4 14
2.7.1 LiFePO4結構 14
2.7.2 LiFePO4所受限制 16
2.8 LiFePO4材料的改質 18
2.8.1改善鋰離子低遷移率的問題 18
2.8.2 提升導電性 22
2.9 實驗動機與目的 31
第三章 實驗方法與步驟 33
3.1 實驗流程 34
3.2 LiFePO4/C陰極材料合成 38
3.2.1 增量回流法合成LiFePO4前驅物 38
3.2.2 以蔗糖碳源包碳 38
3.2.3 以蔗糖為碳源混摻rGO包碳 39
3.2.4 以蔗糖碳源添加二茂鐵包碳 41
3.3 半電池組裝 42
3.3.1 電極片製備 42
3.3.2 壓製鈕扣型電池 43
3.4 充放電測試 44
3.5 實驗使用儀器介紹 45
第四章 結果與討論 48
4.1單倍與增量合成LiFePO4前驅物比較 49
4.2單倍與增量合成蔗糖包覆熱處理粉末比較 58
4.3提升熱處理溫度對LiFePO4/C的影響 63
4.3.1合成之LiFePO4/C鑑定 64
4.3.2 不同熱處理溫度下電池充放電測試比較 76
4.4混摻rGO對LiFePO4/C的影響 81
4.4.1混摻rGO之LiFePO4/C鑑定 82
4.4.2 混摻rGO之LiFePO4/C充放電測試 90
4.5添加二茂鐵催化劑對LiFePO4/C的影響 96
4.5.1二茂鐵催化之LiFePO4/C鑑定 97
4.5.2 二茂鐵催化之LiFePO4/C充放電測試 101
4.6 提升充電速率之測試 105
第五章 結論 110
參考文獻 111

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