為了克服純矽負極材料在電池充放電過程中因破裂所導致電池壽命不佳的問題，本研究利用低成本且具可調控性的無電鍍鎳法並施以熱處理將矽奈米粉末加以改質，成功地製備Si@Ni、Si@NiO與Si@NiSi2等不同的矽基奈米複合材料，並且利用SEM、XRD、TEM、四點量測與電池循環測試系統，系統性地分析彼此間的形貌與結構如何影響其電性與電化學性質。
使用一階段未添加額外還原劑的Self-reducing method製程，在退火前後分別得到的Si@Ni與Si@NiO之複合材料，於TEM影像中可清楚地看見矽因還原鎳離子的同時會氧化並生成一層SiO2，並介於功能性塗層(Ni與NiO)與矽材之間，使得兩者之電化學性質較純矽材料而言雖已有提升但仍不滿意。
倘若使用兩階段的Self-reducing method + Electroless nickel deposition(需添加額外還原劑)製程，在退火後所得到的Si@NiSi2之複合材料，於TEM影像中可看到，因第一階段之短暫製程僅提供Ni達孕核之效，故上述之SiO2生成量不多，再經歷第二階段的晶粒成長與熱處理後，NiSi2於矽表面的包覆性獲得增益並可緩衝矽於充放電過程的激烈體積變化，進而使得電池在0.1 C的充放電速率下歷經70圈測試後，電容值為1391 mAh/g且電容維持率可高達86.6%。

Compared with graphite, a common-used materials for anodes in batteries, silicon (Si) has been proposed to be the most promising choice for next-generation anodes due to its capacity, which is ten times higher than graphite. However, the practical use of Si anode material is impeded by its poor cyclability resulting from the strain induced pulverization cuased by the severe volume change during charge/discharge. In this thesis, we successfully fabricate different functional coating on the Si surface to depreess the tremedous volume change of Si and prolong the batteries life. Si@Ni and Si@NiO nanocomposites were synthesized by one-step (self-reducing method, SR) electroless nickel plating without/with heat treament, and Si@NiSi2 nanocomposites were obtained by two-step (SR + Electroless Nickel deposition, EN) process with heat treament. The charge retention after 100 cycles are estimated to be 58.6% and 68.2% for Si@Ni and Si@NiO electrode, respectively. After 70 cyclic tests, capacity retention of batteries could be significantly improved from 23.4% to 86.6% by replacing pristine-Si with Si@NiSi2 nanocomposite. This results suggest that the NiSi2 could be a competent buffer layer to effectively buffer the volume change of silicon and promote the battery efficiency.

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