纖維基鋰離子電容器的構(gòu)建及電化學(xué)性能研究
發(fā)布時間：2019-03-22 08:56
【摘要】：本論文創(chuàng)新性地提出了一種自支撐全纖維基鋰離子電容器的構(gòu)建方法。利用靜電紡絲工藝以及簡單的熱處理方法分別制備了柔性酚醛基介孔炭納米纖維和聚丙烯腈/木質(zhì)素基復(fù)合炭納米纖維,通過優(yōu)化配比選擇最佳的納米炭纖維薄膜電極。之后將預(yù)嵌鋰后的聚丙烯腈/木質(zhì)素基復(fù)合炭納米纖維作為負極,跟正極酚醛基介孔炭納米纖維組裝成全纖維基鋰離子電容器。分別對正、負極材料的結(jié)構(gòu)、形貌以及組裝成器件的電化學(xué)性能作了較為系統(tǒng)的研究。首先,以熱固性酚醛樹脂為炭前軀體,嵌段共聚物F127為模板劑,聚乙烯醇縮丁醛為助紡劑,通過靜電紡絲和炭化過程制備了柔性酚醛基介孔炭納米纖維。通過優(yōu)化配比,得到具有豐富介孔結(jié)構(gòu)的炭納米纖維。并且將其直接作為自支撐活性材料組裝成水系電容器,在0.05 A g-1的電流密度下,纖維電極獲得139.6 F g-1的放電比電容量;當電流密度達到5 A g-1時,比電容仍然能夠達到97.34 F g-1,證明酚醛基介孔炭纖維杰出的倍率性能。其次,以聚丙烯腈和木質(zhì)素做為炭源,通過靜電紡絲制備聚丙烯腈/木質(zhì)素基復(fù)合炭納米纖維。優(yōu)化聚丙烯腈和木質(zhì)素的配比,將其分別組裝成鋰離子半電池,獲得具有優(yōu)秀倍率性能以及長循環(huán)穩(wěn)定性的復(fù)合炭納米纖維PL-5/5電極。并將其進行改性,成功地構(gòu)建了相鄰纖維互相焊接且具有介孔通道的復(fù)合炭納米纖維膜,纖維電極展現(xiàn)出了 384.4mAhg-1的可逆容量,以及大電流充放電(5Ag-1)條件下,仍能夠保持較好的放電容量127.7 mAh g-1,并且其放電時間僅為91s。最后,以酚醛基介孔炭納米纖維作為正極活性材料,預(yù)嵌鋰后的聚丙烯腈/木質(zhì)素基復(fù)合炭納米纖維作為負極活性材料,在沒有導(dǎo)電劑以及集流體的情況下,成功的構(gòu)建了自支撐全纖維基鋰離子電容器。通過電化學(xué)性能研究,發(fā)現(xiàn)當能量密度為72.62 Whkg-1時,功率密度為97.62 Wkg-1;并且當能量密度為33.05 Wh kg-1,功率密度可高達11.89 kWkg-1,證明其優(yōu)秀的能量和功率特性;并且在0.5 Ag-1的電流密度下經(jīng)過2100個循環(huán)之后,仍然能保持初始容量的91.94%,進一步說明其優(yōu)秀的循環(huán)穩(wěn)定性。
[Abstract]:In this paper, a novel method of constructing self-supporting all-fiber based lithium-ion capacitors is proposed. Flexible phenolic-based mesoporous carbon nanofibers and polyacrylonitrile / lignin-based composite carbon nanofibers were prepared by electrospinning and simple heat treatment. The best carbon fiber thin-film electrodes were selected by optimizing the ratio of carbon nanofibers to polyacrylonitrile / lignin-based carbon nanofibers. Then the polyacrylonitrile / lignin-based composite carbon nanofibers were used as negative electrodes and the positive phenolic-based mesoporous carbon nanofibers were assembled to form all-fiber-based lithium-ion capacitors. The structure, morphology and electrochemical performance of positive and negative materials were studied systematically. Firstly flexible phenolic-based mesoporous carbon nanofibers were prepared by electrospinning and carbonization using thermosetting phenolic resin as carbon precursor block copolymer F127 as template and polyvinyl butyral as spinning aid. Carbon nanofibers with rich mesoporous structure were obtained by optimizing the ratio. At the current density of 0.05A 路g ~ (- 1), the discharge specific capacitance of 139.6 F / g 路L ~ (- 1) was obtained at the current density of 0.05A 路g ~ (- 1), which was assembled directly as a self-supporting active material. When the current density reaches 5 A g ~ (- 1), the specific capacitance can still reach 97.34 F / g ~ (- 1), which proves that the phenolic-based mesoporous carbon fiber has excellent ratio performance. Secondly, polyacrylonitrile / lignin composite carbon nanofibers were prepared by electrospinning using polyacrylonitrile and lignin as carbon source. The ratio of polyacrylonitrile (pan) and lignin (lignin) was optimized and assembled into lithium ion semi-battery respectively. The composite carbon nanofiber PL-5/5 electrode with excellent performance and long cycle stability was obtained. The composite carbon nanofiber membrane with mesoporous channels and welded adjacent fibers was successfully constructed. The reversible capacity of 384.4mAhg-1 and the high current charge / discharge (5Ag-1) condition of the fiber electrode were demonstrated. It is still able to maintain a good discharge capacity of 127.7 mAh / g / kg, and the discharge time is only 91 s. Finally, phenolic-based porous carbon nanofibers were used as positive active materials, polyacrylonitrile / lignin-based composite carbon nanofibers pre-intercalated with lithium were used as negative active materials. The self-supporting all-fiber-based lithium-ion capacitor was successfully constructed. It is found that when the energy density is 72.62 Whkg-, the power density is 97.62 Wkg-1;. When the energy density is 33.05 Wh kg-1, the power density can be up to 11.89 kWkg-1, to prove its excellent energy and power characteristics. After 2100 cycles at the current density of 0.5 Ag-1, the initial capacity can still be kept 91.94%, which further explains its excellent cycle stability.
【學(xué)位授予單位】：天津工業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TM53
本文編號：2445450
[Abstract]:In this paper, a novel method of constructing self-supporting all-fiber based lithium-ion capacitors is proposed. Flexible phenolic-based mesoporous carbon nanofibers and polyacrylonitrile / lignin-based composite carbon nanofibers were prepared by electrospinning and simple heat treatment. The best carbon fiber thin-film electrodes were selected by optimizing the ratio of carbon nanofibers to polyacrylonitrile / lignin-based carbon nanofibers. Then the polyacrylonitrile / lignin-based composite carbon nanofibers were used as negative electrodes and the positive phenolic-based mesoporous carbon nanofibers were assembled to form all-fiber-based lithium-ion capacitors. The structure, morphology and electrochemical performance of positive and negative materials were studied systematically. Firstly flexible phenolic-based mesoporous carbon nanofibers were prepared by electrospinning and carbonization using thermosetting phenolic resin as carbon precursor block copolymer F127 as template and polyvinyl butyral as spinning aid. Carbon nanofibers with rich mesoporous structure were obtained by optimizing the ratio. At the current density of 0.05A 路g ~ (- 1), the discharge specific capacitance of 139.6 F / g 路L ~ (- 1) was obtained at the current density of 0.05A 路g ~ (- 1), which was assembled directly as a self-supporting active material. When the current density reaches 5 A g ~ (- 1), the specific capacitance can still reach 97.34 F / g ~ (- 1), which proves that the phenolic-based mesoporous carbon fiber has excellent ratio performance. Secondly, polyacrylonitrile / lignin composite carbon nanofibers were prepared by electrospinning using polyacrylonitrile and lignin as carbon source. The ratio of polyacrylonitrile (pan) and lignin (lignin) was optimized and assembled into lithium ion semi-battery respectively. The composite carbon nanofiber PL-5/5 electrode with excellent performance and long cycle stability was obtained. The composite carbon nanofiber membrane with mesoporous channels and welded adjacent fibers was successfully constructed. The reversible capacity of 384.4mAhg-1 and the high current charge / discharge (5Ag-1) condition of the fiber electrode were demonstrated. It is still able to maintain a good discharge capacity of 127.7 mAh / g / kg, and the discharge time is only 91 s. Finally, phenolic-based porous carbon nanofibers were used as positive active materials, polyacrylonitrile / lignin-based composite carbon nanofibers pre-intercalated with lithium were used as negative active materials. The self-supporting all-fiber-based lithium-ion capacitor was successfully constructed. It is found that when the energy density is 72.62 Whkg-, the power density is 97.62 Wkg-1;. When the energy density is 33.05 Wh kg-1, the power density can be up to 11.89 kWkg-1, to prove its excellent energy and power characteristics. After 2100 cycles at the current density of 0.5 Ag-1, the initial capacity can still be kept 91.94%, which further explains its excellent cycle stability.
【學(xué)位授予單位】：天津工業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TM53
【參考文獻】
相關(guān)期刊論文 前2條
1 蔡少偉;;鋰離子電池正極三元材料的研究進展及應(yīng)用[J];電源技術(shù);2013年06期
2 楊紹斌,胡浩權(quán);鋰離子電池[J];遼寧工程技術(shù)大學(xué)學(xué)報(自然科學(xué)版);2000年06期
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