石墨烯複合導電奈米纖維應用於超級電容之製作

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2014

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本研究是利用靜電紡絲(Electrospinning)與靜電噴霧(Electrospray)技術在不鏽鋼纖維收集器表面,製備與複合導電奈米石墨烯(Graphene)纖維之超級電容電雙層電極。藉由奈米纖維之高比表面積(High specific surface area)與Graphene材料之高電容量(High-capacity),以提升整體比電容值。首先,本研究是將高分子聚苯乙烯(Polystyrene, PS)與導電高分子聚苯胺(Polyaniline, PANi)複合成導電高分子溶液,以作為靜電紡絲之基底材料,藉由靜電紡絲技術將導電高分子噴射成奈米纖維至不鏽鋼基板,形成高比表面積之電極;接著利用分散於N-甲基吡咯烷酮(N-methyl-2-pyrrolidone, NMP)溶劑的Graphene溶液,以靜電噴霧噴灑出霧狀液珠,使電極表面附著Graphene,以增加其電容量;將兩塊對襯之電極中間放置隔離膜浸入5.5 M KOH電解液中並完成元件封裝,並以循環伏安法之元件性能評估。本研究製備出之PS:PANi導電奈米纖維其平均電阻值約4.4 M 歐姆,導電率約為27 uS/cm,並在2.5 V時成功地點亮紅色LED。此外,在奈米纖維上噴灑Graphene,並透過拉曼光譜分析該材料的D band、G band與2D band峰值,表示利用本研究的電噴霧技術已具備將Graphene噴灑於奈米纖維表面之能力。此外,並以循環伏安法分析具PS:PANi:Graphene電極的超級電容,該電流與電壓之掃描圖形面積可大幅增加,顯示充放電能力相當優異。經計算後PS nanofiber、PS:PANi nanofiber、PS:Graphene nanofiber與PS:PANi:Grapene nanofiber四種電極的比電容值,分別為14.83 F/g、51 F/g、60.38 F/g、133.33 F/g。實驗結果顯示,結合PS奈米纖維的高比表面積、PANi的導電性與Graphene高電容量等優點之電極,可提升整體電容器之性能。
In this study, the electrospinning and electrospray techniques are used to prepare for Graphene/conductive nanofibers on the stainless steel plate as the supercapacitors where the nanofibers act as the current collector and electrodes of electrical double-layer. Due to the conductive nanofibers with high specific surface area and Graphene (G) with high capacitance, the overall specific capacitance of the capacitor can be increased. Firstly, the polystyrene (PS) and polyaniline (PANi) are mixed as a conductive polymer solution, which is electrospun as nanofibers on the stainless steel plate and form electrodes with high specific surfaces. To increase the capacity of a capacitor, the Graphene dispersed in N-methyl-2-pyrrolidone (NMP) solvent is electrosprayed on the surface of the nanofibers. The pair of electrodes and membrane separator can be assembled together and then the aqueous 5.5 M KOH electrolyte is dropped and sealed in the capacitor. Finally, the supercapacitors are tested by cyclic voltammetry for the values of performance. The average resistance and electrical conductivity of conductive PS:PANi nanofibers are 4.4 M ohm and 27 uS/cm, respectively. The red LED is illuminated with conductive nanofibers as the connecting wire at 2.5 V. By the Raman spectra measurement, the D band, G band and 2D band are obtained in PS:G and PS:PANi:G electrodes. It indicates the Graphene is sprayed on the surface of the nanofibers. The scanning area of current and voltage can be increased significantly in the capacitor with PS:PANi:G electrodes, the calculated specific capacitances (F/g) are 14.83 (PS), 51 (PS:PANi), 60.38 (PS:G), and 133.33 (PS:PANi:G) under various nanofibers electrodes, respectively. The results demonstrate that the combination of conductive PS:PANi nanofibers and Graphene with high capacitance can improve the performance of overall supercapacitors.

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靜電紡絲技術, 靜電噴霧技術, 超級電容, 奈米纖維, 石墨烯, 聚苯胺, electrospinning, electrospray, supercapacitor, nanofibers, Graphene, polyaniline (PANi)

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