碳納米管橋接rGO/MXene光纖，用于高性能光纖超級電容器

1成果簡介

電極框架的定向構(gòu)造與離子/電子傳輸路徑的對齊對電化學(xué)過程至關(guān)重要。然而，傳統(tǒng)制備策略存在工藝復(fù)雜、難以實現(xiàn)規(guī)模化生產(chǎn)等瓶頸。本文，浙江大學(xué)張玲潔、Ningzhong Bao等在《ADVANCED MATERIALS》期刊發(fā)表名為“Flow-Regime-Controlled Fabrication of CNT-Bridged Vertically Aligned rGO/MXene Fibers for High-Performance Fiber Supercapacitors”的論文，研究開發(fā)了一種流體驅(qū)動濕法紡絲策略，用于制備碳納米管（CNT）橋接的垂直取向氧化石墨烯（rGO）/MXene纖維（CNT-VA-GMFs）。

通過精確調(diào)控流動模式，垂直排列的rGO/MXene納米片與CNT橋接結(jié)構(gòu)協(xié)同構(gòu)建出：開放多孔通道實現(xiàn)快速離子傳輸，連續(xù)導(dǎo)電網(wǎng)絡(luò)保障高效電子轉(zhuǎn)移，豐富活性位點提升電荷存儲能力。由此制備的CNT-VA-GMF電極在H?SO?電解液中展現(xiàn)出優(yōu)異的離子傳輸性能、卓越的比電容（740 F g?1）及出色的長期循環(huán)穩(wěn)定性（30,000次循環(huán)后容量保持率達(dá)98%）。組裝的柔性不對稱超級電容器在保持強勁機械柔韌性的同時，實現(xiàn)了224Wh kg?1 （在1200W kg?1條件下）的卓越能量密度。

2圖文導(dǎo)讀

圖1、a) Schematic diagram of the flow-driven wet-spinning process for CNT-VA-GMF; b) Front-view and c) cross-sectional micro-CT images of CNT-VA-GMF; d) Front-view and cross-sectional SEM images of CNT-VA-GMF; e) High-magnification SEM and f) TEM images of CNT-VA-GMF; g) EDS elemental mapping of Ti and C in CNT-VA-GMF; h) Structural schematic of CNT-VA-GMF; i) N2 adsorption-desorption isotherms of GMF, VA-GMF, and CNT-VA-GMF.

圖2、Flow field variation of GO dispersion with crosslinker ratio of a) 30%, and b) 0%. Part I: Calculated velocity distribution in the expansion channel and in situ polarized light microscopy images of the corresponding region; Part II: SEM images of fibers formed under corresponding condition, and Schematic of GO nanosheet alignment in plug flow versus laminar flow (The detailed trajectories of GO nanosheets were given in Figure S12, Supporting Information). c) Viscosity of GO dispersions with varying crosslinker ratios; d) Calculated shear rate profiles across the expansion channel width.

圖3、Electrochemical performance in 3 m H2SO4 electrolyte. a) CV curves of GMF, VA-GMF, CNT-VA-GMF, and VA-GF (vertical graphene fiber) at 10 mV s?1; b) GCD curves of GMF, VA-GMF, CNT-VA-GMF, and VA-GF at 1 A g?1; c) Gravimetric specific capacitance of samples at different scan rates; d) Nyquist plots of GMF, VA-GMF, and CNT-VA-GMF; e) Capacitive contributions of CNT-VA-GMF at different scan rates; f) Gravimetric specific capacitance of vertical fibers with varying MXene content; electrode current density, ion migration trajectory, and electrolyte concentration distribution for g) onion ring structure, h) hetero-vertical structure, and i) CNT-bridged vertical structure; j) Ion migration rate versus normalized fiber depth.

圖4、Electrochemical performance of FSC.

3小結(jié)

綜上所述，通過精確調(diào)控膨脹流與塞流之間的流動狀態(tài)轉(zhuǎn)變，成功制備了基于二維材料的纖維，其具有碳納米管橋接的垂直取向rGO/MXene結(jié)構(gòu)。原位極化顯微鏡與計算流體動力學(xué)模擬揭示，垂直結(jié)構(gòu)的形成不僅需要膨脹流的取向效應(yīng)，還需塞流作用以穩(wěn)定二維納米片的定向垂直結(jié)構(gòu)。具有該垂直構(gòu)型的CNT-VA-GMF通過流驅(qū)動濕法紡絲技術(shù)實現(xiàn)了規(guī)模化連續(xù)制備。令人鼓舞的是，垂直有序孔結(jié)構(gòu)、MXene/rGO異質(zhì)界面與CNT橋接骨架的協(xié)同作用，使CNT-VA-GMF具備縮短的離子擴散路徑、增強的電子導(dǎo)電性及豐富的電化學(xué)活性位點。由此，CNT-VA-GMF實現(xiàn)740 F g?1的比電容及超長循環(huán)穩(wěn)定性（在H?SO?電解液中經(jīng)30,000次循環(huán)后保持98%容量），驗證其卓越的電荷存儲能力與可逆離子吸附/脫附動力學(xué)特性。此外，組裝的FSC展現(xiàn)出224 Wh kg-1的能量密度、延長循環(huán)壽命（20,000次循環(huán)后保持率達(dá)98%）及優(yōu)異柔韌性，成功驅(qū)動LED燈、電風(fēng)扇和玩具船等應(yīng)用實證。

文獻：

https://doi.org/10.1002/adma.202516561

來源：材料分析與應(yīng)用