合成的多壁碳纳米管(MWCNT)长度通常在微米范围,且成宏观缠绕状,不利于电解质离子在MWCNT内管中的扩散和传质,也影响其在电容器电极材料中的研究及应用。本研究选择Hummers方法在横向和纵向同时切割MWCNTs形成管状类石墨烯片(TGS),在70℃热水浴中反应60min制备了TGS/MnO2复合物。通过场发射扫描电子显微镜(FESEM)、粉末X射线衍射(XRD)和拉曼光谱对其形貌和微观结构进行表征,结果表明,在TGS表面成功地沉积了非晶态MnO2。电化学测试表明,TGS/MnO2复合物在扫描速率为2mV/s时的比电容高达236F/g(在100mV/s时达到127F/g),远高于MWCNTs(15F/g)、TGS(88F/g)和MWCNTs/MnO2混合材料(111F/g)。而且TGS/MnO2复合电极具有良好的循环性能,1000次循环后电容保持率高达97%。
The lengths of synthesized multi-walled carbon nanotubes (MWCNTs) are usually in the micrometer range and intertwining,which is not conducive to the diffusion and mass transfer of electrolyte ions in the MWCNT inner tube,and also affects its research and application in supercapacitors.Herein,the Hummers method was selected to cut MWCNTs horizontally and vertically simultaneously to form tube-like graphene sheets (TGS),and TGS/MnO2 composites were prepared by reacting in a 70℃ water bath for 60min.The morphology and microstructure were characterized by field emission scanning electron microscope (FESEM),powder X-ray diffraction (XRD) and Raman spectroscopy.The results showed that amorphous MnO2 was successfully deposited on the surface of TGS.Electrochemical testing indicated that the specific capacitance of TGS/MnO2 composite was as high as 236F/g (127F/g at 100 mV/s) at a scan rate of 2mV/s,which was much higher than that of MWCNTs (15F/g),TGS (88F/g),and MWCNTs/MnO2 hybrid materials (111F/g).Moreover,the TGS/MnO2 composite electrode had good cycling performance,with a capacitance retention rate of up to 97% after 1000 cycles.
[1] Du W,Wang X N,Sun X Q,et al.Nitrogen-doped hierarchical porous carbon using biomass-derived activated carbon/carbonized polyaniline composites for supercapacitor electrodes[J].J Electroanal Chem,2018,827:213-220.
[2] Lu S Y,Jin M,Zhang Y,et al.Chemically exfoliating biomass into a graphene-like porous active carbon with rational pore structure,good conductivity,and large surface area for high-performance supercapacitors[J].Adv Energy Mater,2017,8:1702545-10702554.
[3] Zhang D Y,She W N,Wang J R,et al.High-specific-energy aqueous supercapacitor with extended operating potential using trichloroacetic acid electrolyte[J].J Power Sources,2022,527:231211.
[4] Xiao B H,Lin R T,Xiao K,et al.A highly compressible,nitrogen doped carbon foam based all pseudo-capacitance asymmetric supercapacitors[J].J Power Sources,2022,530:231307.
[5] Liang C P,Tang W H,Gao Y K,et al.Preparation and electrochemical properties of S/porous carbon nanotube composites[J].Chinese J Inorg Chem,2022,5:805-811.
[6] Jeon S,Jeong S H,Yoo H,et al.RuO2nanorods on electrospun carbon nanofibers for supercapacitors[J].ACS Appl Nano Mater,2020,3:3847-3858.
[7] Han X,Wang B Q,Yang C,et al.Inductive effect in Mn-doped NiOnanosheet arrays for enhanced capacitive and highly stable hybrid supercapacitor[J].ACS Appl Energy Mater,2019,2:2072-2079.
[8] Liu R,Ma L N,Huang S,et al.Large areal mass,high scalable and flexible cobalt oxide/graphene/bacterial cellulose electrode for supercapacitors[J].J Phys Chem C,2016,120:28480-28488.
[9] Cui S Z,Wang F Q,Sun K J,et al.High-performance hybrid supercapacitors based on Ce-doped NiMoO4nanosheets and Fe3O4@Bi2O3nanoarrays[J].J Phys Chem C,2021,125:18129-18140.
[10] Drieschner S,Seckendorff M,Del C E,et al.Uniformly coated highly porous graphene/MnO2 foams for flexible supercapacitors[J].Nanotechnology,2018,29:116444-116461.
[11] Zhang A Q,Gao R,Hu L Y,et al.Rich bulk oxygen Vacancies-Engineered MnO2 with enhanced charge transfer kinetics for supercapacitor[J].Chem Eng J,2021,417:129186.
[12] Zhu Y Q,Xu H,Chen P D,et al.Electrochemical performance of polyaniline-coated γ-MnO2 on carbon cloth as flexible electrode for supercapacitor[J].Electrochim Acta,2022,413:140146.
[13] Guo W,Yu C,Li S F,et al.Strategies and insights towards the intrinsic capacitive properties of MnO2 for supercapacitors:challenges and perspectives[J].Nano Energy,2019,57:459-472.
[14] Abdollahi A,Abnavi A,Ghasemi F,et al.Facile synthesis and simulation of MnO2 nanoflakes on vertically aligned carbon nanotubes,as a high-performance electrode for Li-ion battery and supercapacitor[J].Electrochim Acta,2021,390:138826.
[15] Yang Z Y,Zhao Y F,Xiao Q Q,et al.Controllable growth of CNTs on graphene as high-performance electrode material for supercapacitors[J].ACS Appl Mater Interfaces,2014,6:8497-8504.
[16] Chee W K,Lim H N,Zainal Z,et al.Flexible graphene-based supercapacitors:a review[J].J Phys Chem C,2016,120:4153-4172.
[17] Yang Z F,Tian J R,Yin Z F,et al.Carbon nanotube- and graphene-based nanomaterials and applications in high-voltage supercapacitor:a review[J].Carbon,2019,141:467-480.
[18] Jin F Z,Li M J,Xie L X,et al.Selenium-doped carbon nanotubes/nickel selenide coaxial nanocables for energy storage[J].J Power Sources,2021,514:230587.
[19] Lakra R,Kumar R,Sahoo P K,et al.A mini-review:graphene based composites for supercapacitor application[J].Inorg Chem Commun,2021,133:108929.
[20] Nanaji K,Sarada B V,Varadaraju U V,et al.A novel approach to synthesize porous graphene sheets by exploring KOH as pore inducing agent as well as a catalyst for supercapacitors with ultra-fast rate capability[J].Renew Energ,2021,172:502-513.
[21] Liu Y P,Qin Z Y,Shen Y Y,et al.Tuning spatial distribution of graphene sheets composited with polyaniline nanofiber array on carbon cloth towards ultrahigh areal energy density flexible supercapacitors[J].Carbon,2022,186:688-698.
[22] Tonga Z W,Yuana Y F,Zhang D,et al.Mn3O4nanocrystalline@carbon nanotube-carbon nanotube for long-lifetime and excellent rate-capability zinc-ion storage[J].Electrochim Acta,2022,403:139649.
[23] Xiao J P,Tong H,Jin F Q,et al.Heterostructure NiS2/NiCo2S4 nanosheets array on carbon nanotubes sponge electrode with high specific capacitance for supercapacitors[J].J Power Sources,2022,518:230763.
[24] Cena T,Chena L,Zhang X G,et al.A novel fiber-shaped asymmetric supercapacitor prepared by twisting carbon fiber/carbon nanotube/MnO2 and carbon fiber/carbon nanotube/polypyrrole electrodes+[J].Electrochim Acta,2021,367:137488.
[25] Hummers W S,Offeman R E.Preparation of graphitic oxide[J].Jam Chem Soc,1958,80:1339-1339.
[26] Wang H W,Wang Y L,Hu Z A,et al.Cutting and unzipping multiwalled carbon nanotubes into curved graphene nanosheets and their enhanced supercapacitor performance[J].ACS Appl Mater Interfaces,2012,4:6827-6834.
[27] Kierkowicz M,Pach E,Santidrian A,et al.Comparative study of shortening and cutting strategies of single-walled and multi-walled carbon nanotubes assessed by scanning electron microscopy[J].Carbon,2018,139:922-932.
[28] Wang X X,Wang J N,Chang H,et al.Preparation of short carbon nanotubes and application as an electrode material in Li-ion batteries[J].Adv Funct Mater,2007,17:3613-3618.
[29] Kumar S,Twinkle,Kau M.Carbon nanotube-derived highly conductive graphene nanoribbons for electronic applications[J].MaterChem Phys,2021,259:123967.
[30] Yang Q,Chen Y D,Duan X G,et al.Unzipping carbon nanotubes to nanoribbons for revealing the mechanism of nonradical oxidation by carbocatalysis[J].Appl Catal B Environ,2020,276:119146.
[31] Li Z P,Wang J Q,Liu S,et al.Synthesis of hydrothermally reduced graphene/MnO2 composites and their electrochemical properties as supercapacitors[J].J Power Sources,2011,196:8160-8165.
[32] Szabo T,Tomba E,Illes E,et al.Enhanced acidity and pH-dependent surface charge characterization of successively oxidized graphite oxides[J].Carbon,2006,44:537-545.
[33] Lu Y S,Huang L J,Guo Y N,et al.Theoretical insights into origin of graphene oxide acidity and relating behavior of oxygen-containing groups in water[J].Carbon,2021,183:355-361.
[34] Wang H,Fu Q,Pan C X.Green mass synthesis of graphene oxide and its MnO2 composite for high performance supercapacitor[J].Electrochim.Acta,2019,312:11-21.
[35] Tang X N,Zhu S K,Ning J,et al.Charge storage mechanisms of manganese dioxide-based supercapacitors:a review[J].New Carbon Mater,2021,36:702-710.
[36] Shresthaa D,Maensiri B,Wongpratat U,et al.Shore robust derived activated carbon decorated with manganese dioxide hybrid composite for improved capacitive behaviors[J].J Environ Chem Eng,2019,7:103227.
[37] Ma S B,Ahn K Y,Lee E S,et al.Synthesis and characterization of manganese dioxide spontaneously coated on carbon nanotubes[J].Carbon,2007,45:375-382.
[38] Zhao Y,Hao H L,Song T L,et al.MnO2-graphene based composites for supercapacitors:synthesis,performance and prospects[J].J Alloy Compd,2022,914:165343.
[39] Yan J,Fan Z J,Wei T,et al.Fast and reversible surface redox reaction of graphene-MnO2 composites as supercapacitor electrodes[J].Carbon,2010,3825-3833.
[40] Vimuna V M,Karthika U M,Saji Alex,et al.Microsphere rGO/MnO2 composites as electrode materials for high-performance symmetric supercapacitors synthesized by reflux reaction[J].Inorg Chem Commun,2022,27:109508.
[41] Chai Y Q,Li Z P,Wang J Q,et al.Construction of hierarchical holey graphene/MnO2 composites as potential electrode materials for supercapacitors[J].J Alloy Compd,2019,775:1206-1212.
[42] Li Z Q,Tian M W,Sun X T,et al.Flexible all-solid planar fibrous cellulose nonwoven fabric-based supercapacitor via capillarity-assisted graphene/MnO2 assembly[J].J Alloy Compd,2019,782:986-994.
[43] Ullah S,Yu J L,Liu H C,et al.Fabrication of MnO2-carbonized cotton yarn derived hierarchical porous active carbon flexible supercapacitor electrodes for potential applications in cable-type devices[J].Appl Surf Sci,2019,487:180-188.
基金资助
国家自然科学基金项目(21865027)
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