碳化矽(SiC)是一具有高化學穩定性、高硬度、高導熱性以及低熱膨脹係數的陶瓷半導體材料[1]。因此本研究以聚丙烯腈(polyacrylonitrile, PAN)高分子溶液導入不同含量的二氧化矽(Silicon dioxide, SiO2)，利用電紡絲技術製備出不同碳矽比例的SiO2/PAN複合奈米纖維，再以1400oC高溫鍛燒，使SiO2與PAN形成的碳纖維反應成為碳化矽/奈米碳纖複合材料。
以掃描式電子顯微鏡之元素分布圖(EDS mapping)觀察紡製的纖維內SiO2粒子均勻分散在複合奈米纖維內；經過高溫鍛燒後的奈米纖維由傅立葉轉換紅外線光譜儀(FTIR)分析，在797cm-1位置Si-C的吸收峰強度大幅增強，而1070cm-1位置Si-O吸收峰強度變弱，表示碳纖維與SiO2反應形成SiC；由X射線繞射儀(XRD)在2θ為35.7°、60.0°、71.8°處觀察到-SiC結晶的特徵繞射峰，證實製備具有碳化矽材料的奈米纖維；由熱重分析儀(TGA) 在空氣氣氛下，碳矽比為20.58、6.86和3.43的SiC/Carbon複合材料分別剩下的重量百分比分別為16wt%、38 wt%及58 wt%，隨著碳矽比例下，剩餘重量變多，得到SiC材料較多；由X射線光電子能譜儀(XPS)來鑑定鍛燒後不同碳矽比之元素含量與元素鍵結，碳矽比愈小，C 1s比例下降，Si 2p比例上升；拆解C 1s有C-C鍵與C-Si鍵，隨著碳矽比降低C-Si特徵峰增強；拆解Si 2p有Si-C鍵與Si-O鍵，隨著碳矽比降低Si-C特徵峰增強，Si-O減弱，得知Si-O反應的更完全。
將鍛燒後得到的碳化矽/奈米碳纖複合材料極片進行半電池組裝，經過電池測試後，C/Si=3.43比例在0.1C放電電容量為103mAh/g，1C放電電容量92mAh/g，10C放電電容量88mAh/g，至20C時放電電容量仍有85mAh/g；20C所需的時間為0.1C的1/200，大電流放電電容量下降17.5%。與未含碳化矽之奈米碳纖比較，雖然純碳纖在0.1C放電電容量165mAh/g較高，但在10C時放電電容量剩下92mAh/g，下降44.5%，在12C後放電電容急劇降低，內部結構崩壞無法再進行充放電。結果顯示含有碳化矽的奈米纖維能承受瞬間大電流放電，電池的放電電容量還能維持，並以0.1C活化電池之放電電容值沒有降低。
在60度高溫下，碳化矽/奈米碳纖複合材料極片進行半電池組裝，以0.1C放電與室溫放電電容無明顯變化，到10C之放電電容雖然下降50%，但再以0.1C放電仍有90mAh/g。純碳纖負極放電速率無論是在0.1C或提高到10C時效能皆比添加碳化矽奈米碳纖負極差。含有碳化矽之奈米碳纖負極材料之鋰電池可在高溫條件下充放電。
以氧電漿改質SiC/Carbon複合材料後，材料表面形成氧化層為有效的鈍化層，應用在鋰電池負極材料，降低首次不可逆放電電容，同時提高可逆電容。

Silicon carbide (SiC) is a ceramic semiconductor material which has high chemical stability, high hardness, high thermal conductivity and low thermal expansion coefficient. Therefore, this study use polyacrylonitrile (polyacrylonitrile, PAN) polymer solution with different quantities of silica (Silicon dioxide, SiO2) to fabricate different proportions of carbon silicon SiO2/PAN nanofibers composite by electrospinning technique. SiO2 / PAN fibers form SiC / carbon nanofibers composite material at 1400°C.
Observed the spun fibers by EDS mapping, SiO2 particles are uniformly dispersed in the nanofibers composite; High temperature treated nanofibers analyzed by Fourier transform infrared spectrometer (FTIR), the intensity of the absorption peak 797cm-1 Si-C is greatly enhanced, and the intensity of the absorption peak 1070cm-1 Si-O becomes weak. It represents reaction of carbon fibers and SiO2 to form SiC; by X-ray diffraction (XRD), β-SiC crystal characteristic diffraction peaks are observed at 2θ=35.7°、60.0° and 71.8°, confirming the preparation of nanofibers with silicon carbide material; by thermal gravimetric analyzer (TGA) in air, the carbon to silicon ratio of 3.43、6.86 and 20.58 SiC/Carbon composite respectively remain with 16wt%、38wt% and 58wt%, with the proportion decreasing, the remaining weight increasing,obtaining more SiC material; X-ray photoelectron spectroscopy (XPS) identifies the elements content of different proportion of carbon to silicon and element bonding after heat treatment. The smaller the ratio of carbon to silicon, C 1s decreases, and Si 2p increases; Taking apart C 1s to C-C bond and C-Si bond, the carbon to silicon ratio is reduced as C-Si peaks enhanced; Taking apart Si 2p to Si-C bond and Si-O bond, the carbon to silicon ratio is reduced as the Si-C peak enhances, and Si-O peak weakens. We can find that Si -O reacts completely.
Assembling SiC/carbon nanofibers composite as anode material on semi battery after heat treatment of SiO2/PAN nanofibers composite, after battery test, C/Si=3.43 discharge capacity at 0.1C is 103mAh/g, discharge capacity at 1C is 92mAh/g, discharge capacity at 10C is 88mAh/g, and even discharge capacity at 20C remains 85mAh/g; time required for 20C is 200 times longer than 0.1C’s, high-current discharge capacity decreasing 17.5%. Although pure carbon fibers capacity at 0.1C discharge is 165mAh/g, higher than SiC/Carbon nanofibers’, the discharge capacity at 10C is 92mAh/g, reduced 44.5%. The discharge capacity rapidly reduced after 12C, because the internal structure collapsed. The results showed that containing silicon carbide nanofibers can stand transiently high-current discharge, and the battery discharge capacity can be maintained. Reactivation of the battery at 0.1C shows the discharge capacity remains.
Assembling SiC/Carbon nanofibers composite as anode material on semi battery, charge capacity and discharge capacity at 0.1C and at 60°C do not change significantly compared with that in room temperature. Though the discharge capacity decreases 50% at 10C, but reactivation at 0.1C discharge capacity remains 90mAh/g. The high-performance of pure carbon as anode material either at 0.1C or 10C discharge capacity is worse than SiC/Carbon nanofibers composite’s. Li-ion battery containing SiC/Carbon nanofibers composite as anode material can be charged and discharged at high temperatures.
After oxygen plasma modifies SiC / Carbon Composites, oxide layer is formed on the surface as an active passivation layer. Applications on the lithium battery anode material decreases first cycle irreversible capacity, while increasing reversible capacity.

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