2004-01-012024-05-17https://scholars.lib.ntu.edu.tw/handle/123456789/692391摘要：在適當的偏壓下，鋰已知能與許多金屬在室溫下形成介金屬，作為鋰離子負極材料而言，這些鋰合金所能提供之理論比電容量是遠大於石墨所能提供。矽(Si)的理論比電容量為最高(Li4.4Si: 4200 mAh/g-Si)。Si本身為一廉價物質，且無造成環境污染之疑慮，其不啻為最佳的待開發材料系統。然而，要達到此一目標需克服幾項困問題，第一為在鋰嵌入與遷出時相伴產生之密度(體積)變化，易造成充放電時電極結構鬆脫與粉化。第二，矽的導電度低，如何搭配適當之助導劑以降低電充放電阻抗亦為待解決之課題。本計劃之主要研究構想在於開發一核殼型Si/Cu複合粉體，以期克服以上所述之困難點。該複合粉體之核(Core)為Si，而殼(Shell)部份為Cu或Cu與CuSix之混合層。Cu為一韌性物質且並不與Li進行電化學反應形成合金，具有建立緩衝架構(buffering matrix)的功能; Cu的導電度高，可有效降低電極片整體的阻抗;希望利用適當的熱處理加強該殼層之機械強度，以期在充放電時能有效降低Si粉體粉化解體的情形。Cu的導電度較石墨更高且更具有&#38765;性。預定研究工作項目包括粉體之合成，並分析量測該<br> Abstract: Si forms intermetallic compounds with several elements under appropriate bias at room temperature. Among them, Si provides the highest theoretical charge capacity (Li4.4Si: 4200 mAh/g-Si)。However, when Si is to be used as a negative electrode material for lithium ion secondary battery, there are serious obstacles, particularly including large volume variation upon charging/discharging and its poor conductivity. The main object of this project is to produce/design core-shell type Si/Cu composite powder for overcome the obstacles. As Cu or CuSix shell does not react with Li and hence it can serve as buffering matrix to help to stabilize the electrode. In addition, the shell can minimize powder pulverization due to volume variation and help to increase electrode conductivity. The Cu shell will be produced by electroless deposition followed by drying and reduction in a fluidized bed. The CuSix solid solutions will be formed by heat treatment above 800 oC also in a fluidized bed.鋰離子二次電池&cedil負極材料矽銅核殼形複合材料lithium ion secondary batterySiCunegative electrodeCore/shell composite