Polyaniline-deposited porous carbon electrode for supercapacitor

Electrodes for supercapacitors were fabricated by depositing polyaniline (PANI) on high surface area carbons. The chemical composition of the PANI-deposited carbon electrode was determined by X-ray photoelectron spectroscopy (XPS). Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to investigate the electrochemical properties of electrodes. An equivalent circuit was proposed to successfully fit the EIS data, and the significant contribution of pseudocapacitance from PANI was thus identified. A comparative analysis on the electrochemical properties of bare-carbon electrodes was also conducted under similar conditions. The performance of the capacitors equipped with the resulting electrodes in 1 M H₂SO₄ was evaluated by constant current charge-discharge cycling within a potential range from 0 to 0.6 V. The PANI-deposited electrode exhibits high specific capacitance of 180 F/g, in comparison with a value of 92 F/g for the bare-carbon electrode.     

Fabrication and electrochemical characterization of polyimide-derived carbon nanofibers for self-standing supercapacitor electrode materials

We report the electrochemical performance of aromatic polyimide (PI)-based carbon nanofibers (CNFs), which were fabricated by electrospinning, imidization, and carbonization process of poly(amic acid) (PAA) as an aromatic PI precursor. For the purpose, PAA solution was electrospun into nanofibers, which were then converted into CNFs via one-step (PAA-CNFs) or two-step heat treatment (PI-CNFs) of imidization and carbonization. The FTIR and Raman spectra demonstrated a successful structural evolution from PAA nanofibers to PI nanofibers to CNFs at the molecular level. The SEM images revealed that the average diameter of the nanofibers decreased noticeably via imidization and carbonization, while it decreased slightly with increasing the carbonization temperature from 800 °C to 1000 °C. In case of PI-CNF carbonized at 1000 °C, a porous structure was developed on the surface of nanofibers. The electrical conductivity of PI-CNFs, which was even higher than that of PAA-CNFs, increased significantly from 0.41 to 2.50 S/cm with increasing the carbonization temperature. From cyclic voltammetry and galvanostatic charge/discharge tests, PI-CNF carbonized at 1000 °C was evaluated to have a maximum electrochemical performance of specific capacitance of ~126.3 F/g, energy density of ~12.2 Wh/kg, and power density of ~160 W/kg, in addition to an excellent operational stability. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47846.     

Metal-organic framework (MOF) as a template for syntheses of nanoporous carbons as electrode materials for supercapacitor

Five nanoporous carbons (NPCs) were prepared by polymerizing and then carbonizing carbon precursor of furfuryl alcohol accommodated in a porous metal-organic framework (MOF-5, [Zn₄O(bdc)₃], bdc = 1,4-benzenedicarboxylate) template. The Brunauer-Emmett-Teller (BET) surface areas for five NPC samples obtained by carbonizing at the temperatures from 530 to 1000 °C fall into the range from 1140 to 3040 m² g⁻¹ and the dependence of BET surface areas on carbonization temperatures shows a “V” shape. All the five NPC samples have a pore size distribution centered at about 3.9 nm. As electrode materials for supercapacitor, the NPC samples obtained at the temperatures higher than 600 °C display the ideal capacitor behaviors and give rise to almost constant specific capacitance (above 100 F g⁻¹ at 5 mV s⁻¹) at various sweep rates, which is associated with their mesoporous characteristics. However, the NPC sample with the highest BET surface area (3040 m² g⁻¹) obtained by carbonizing at 530 °C gives a unusually low capacitance (12 F g⁻¹ at 5 mV s⁻¹), which may be attributed to the poor conductivity of the carbon material due to the low carbonization temperature.     

循环伏安法制备聚苯胺/活性炭超级电容器膜电极

采用电化学循环伏安法,在柔性石墨纸基底材料上合成了聚苯胺/活性炭(PANI/AC)复合薄膜。 通过SEM观察了不同扫描圈数下复合薄膜的表面形貌,通过循环伏安(CV)、交流阻抗(EIS)、恒流充放电等电化学测试方法,研究了聚苯胺/活性炭复合电极的电性能。由SEM图谱可知,不同扫描圈数下,聚苯胺/活性炭的形态也有所不同,电化学测试结果表明,以柔性石墨纸为基底材料,扫描圈数在3圈时,不仅比容量较高,达504 F·g^-1,而且循环稳定性较好,经2000次循环后,容量衰减仅为初始容量的14%。     

超级电容器用煤基活性炭研究

为了研究煤基活性炭电极对超级电容器性能的影响规律,根据超级电容器的工作原理,阐述了比表面积、孔径分布、表面官能团、石墨化程度、灰分及粒度对电化学性能的影响。研究表明适宜的中孔比例和粒度有利于电解液的扩散;含氧和含氮官能团可以改善电极的表面润湿性;无定型炭结构孔隙更发达,更适合作为活性炭材料;降低灰分可以提高电极的充放电特性和倍率特性。     

超级电容器电极材料研究最新进展

超级电容器是一种介于传统电容器与化学电源之间的新型储能元件,它具有充电时间短、循环寿命长、功率密度大、能量密度高、适用温度范围宽和经济环保等优势,目前在很多领域都受到广泛关注。本文概述了超级电容器电极材料的研究情况,包括碳基材料、金属氧化物材料及导电聚合物材料等。     

用过期切片面包制备环保超级电容器活性炭电极材料

考虑到世界上每天产生大量的过期面包等过期食品,以过期切片面包为原材料,经碳化、1 mol·L^-1 KOH活化并用稀盐酸中和及去离子水和乙醇洗涤后,制备了过期切片面包活性炭(EBAC)。对过期切片面包活性炭的表面形貌、物相结构、表面官能团、比表面积和孔径分布分别通过扫描电子显微镜(SEM)、X射线衍射(XRD)、傅里叶变换红外光谱(FTIR)、氮气吸脱附(BET)进行了表征。在以3 mol·L^-1 KOH为电解液的三电极体系中,进行了活性炭电极材料的电化学性能测试。充放电曲线显示,在0.5 A·g^-1电流密度下,电极材料比电容达到352 F·g^-1;在5 A·g^-1的电流密度下循环1000次后,比电容保持在99.87%,展示出良好的循环稳定性。交流阻抗测试得到的Nyquist图和Bode图则近一步说明了过期切片面包活性炭具有良好的超级电容器性能。     

Feasibility of bamboo-based activated carbons for an electrochemical supercapacitor electrode

This study focused on the preparation and electrochemical properties of bamboo-based activated carbons (ACs) through carbonization and subsequent activation with steam and non-aqueous electrolyte solutions. The specific surface areas and the capacitances of samples ranged from 445 to 1,025 m²/g and from 5 to 60 F/g, respectively, depending on the activation conditions. The sample activated at 900 ‡C for 60 min under our experimental conditions exhibited the highest capacitance and the largest specific surface area.     

浅谈超级电容器电极材料的研究进展

介绍了碳材料、金属氧化物和导电聚合物及其复合材料等超级电容器电极材料的研究现状,并指出其发展方向是制备性能优异的复合材料和实现材料纳米化。     

The composite material based on Dawson-type polyoxometalate and activated carbon as the supercapacitor electrode

A supercapacitor electrode assembled from activated carbon (AC) and (NH₄)₆[P₂Mo₁₈O₆₂]·14.2H₂O (P₂Mo₁₈) was fabricated for the first time, and showed remarkable electrochemical performance ascribed to the synergy of the double layer capacitance of AC and the pseudocapacitance of P₂Mo₁₈. The investigations indicate that the AC/P₂Mo₁₈ electrode exhibits a specific capacitance of 275 F g^− 1 at a high current density of 6 A g^− 1, which is substantially larger than the 182 F g^− 1 of the AC electrode. In addition, the AC/P₂Mo₁₈ electrode possesses a remarkable rate capability (89%) when the current density is increased from 2 to 6 A g^− 1.     

Polyaniline/multi-walled carbon nanotube composites with core-shell structures as supercapacitor electrode materials

Composites with core-shell structures consisting of polyaniline and carbon nanotubes were prepared via in situ polymerization of aniline monomers by using multi-walled carbon nanotubes with minimized defects as templates. The strong interaction in such conjugated systems greatly improves the charge-transfer reaction between polyaniline and the carbon nanotube. Influences of the thickness of the polyaniline layer on the surface of the carbon nanotubes on the electrochemical properties of the resulting composites are discussed. The highest specific capacitance of 560 F/g was achieved by using a composite with 66 wt% polyaniline content as the supercapacitor electrode. Additionally, enhancement of the capacity retention was observed, with the composite losing only 29.1% of the maximum capacity after 700 cycles, and then remaining stable.     

Chemical vapor-deposited carbon nanofibers on carbon fabric for supercapacitor electrode applications

Entangled carbon nanofibers (CNFs) were synthesized on a flexible carbon fabric (CF) via water-assisted chemical vapor deposition at 800°C at atmospheric pressure utilizing iron (Fe) nanoparticles as catalysts, ethylene (C₂H₄) as the precursor gas, and argon (Ar) and hydrogen (H₂) as the carrier gases. Scanning electron microscopy, transmission electron microscopy, and electron dispersive spectroscopy were employed to characterize the morphology and structure of the CNFs. It has been found that the catalyst (Fe) thickness affected the morphology of the CNFs on the CF, resulting in different capacitive behaviors of the CNF/CF electrodes. Two different Fe thicknesses (5 and 10 nm) were studied. The capacitance behaviors of the CNF/CF electrodes were evaluated by cyclic voltammetry measurements. The highest specific capacitance, approximately 140 F g⁻¹, has been obtained in the electrode grown with the 5-nm thickness of Fe. Samples with both Fe thicknesses showed good cycling performance over 2,000 cycles.     

Facile synthesis of activated carbon/carbon nanotubes compound for supercapacitor application

A large number of carbon nanotubes (CNTs) have been produced commingled in activated mesocarbon microbeads (AMCMBs) activated by potassium hydroxide in a stainless steel container at 900 °C, in which an especial buried-protection method with petroleum coke powders was used to protecting the product during activation. The CNTs were found to be about 50 nm in diameter and characteristic length more than 10 μm. In addition, the AMCMBs/CNTs compound when used for electrode material of electrochemical double-layer capacitors exhibited a specific capacitance of 243 F g^?1 in 6 M KOH aqueous solution.     

四氧化三钴超级电容器电极材料的制备与研究

电极材料是决定电化学电容器性能的一个主要方面,研究与开发高性能的电极材料是人们的研究重点之一.碳电极材料比电容较小;钌等贵重金属氧化物电极材料比电容量虽然很高,但昂贵的价格限制了其实际应用.因此价格低廉、环境友好、同样具有较高氧化还原电容的过渡金属氧化物成为目前超级电容器的研究热点之一.以硝酸钴为原料,以柠檬酸为模板水热合成了前驱体,200 ℃热处理后得到了四氧化三钴.循环伏安、恒流放电等电化学测试表明,200 ℃所得四氧化三钴电极在6 mol/L氢氧化钾溶液中和-0.1～0.5 V (vs. SCE) 电位范围内,具有较好的循环稳定性能,单电极比电容达到442 F/g.为开发高性能的超级电容器电极材料提供了参考.     

碳包覆金属氧化物作为超级电容器电极材料的研究进展

综述了碳包覆金属氧化物作为超级电容器电极材料的最新研究进展。详细介绍了贵重金属氧化物（如RuO2）和廉价金属氧化物（如Fe3O4、SnO2、TiO2、MnO2等）在超级电容器电极材料领域内的应用现状和存在的问题,指出了碳包覆廉价金属氧化物所形成的核/壳结构很好地解决了金属氧化物易溶于电解液、充放电体积易膨胀等问题,展望了其作为超级电容器电极材料在消费电子、航空航天、国防科技等领域中的应用前景。     

Polyimide‐based porous hollow carbon nanofibers for supercapacitor electrode

Porous hollow carbon nanofibers (PHCNFs) using styrene‐acrylonitrile copolymer (SAN) solution as core and polyacrylic acid (PAA) as shell were manufactured by co‐axial electrospinning technique, taking polyvinyl pyrrolidone (PVP) as a pore inducer additive in the shell. The shell thickness of PHCNFs could be adjusted by controlling flow rates of core and shell fluids. The prepared PHCNFs showed excellent electrochemical properties with the high specific capacitance of 221 F g^?1 and superior cycling stability, remaining a capacitance retention of 95% after 5000 cycles under a scan rate of 0.1 V s^?1. In this system, hollow structures bring a 20% capacitance improvement, while the porous morphology brings a 47% capacitance improvement. The attractive performances exhibited by these sponge supercapacitors make them potentially promising candidates for future energy storage systems. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43397.     

夹心型生物碳电极材料的制备及超级电容器性能

选择板栗壳为碳源(CC),炭化后用KOH活化,制得CC700-OH电极材料.通过SEM、TEM、XRD以及BET等对其形貌和性能进行了表征与测试,发现CC700-OH具有孔/片穿插的夹心结构.在电流密度为1 A/g时,比电容为540 F/g,在电流密度为10 A/g下,循环6000圈后比电容仍可保持初始值的98％.在二...     

针状焦基电容器碳质电极材料的制备及电化学性能研究

以煤系针状焦生焦为原料,KOH为活化剂,制备了用于超级电容器电极材料的活性炭。以3 mol/L KOH为电解液,用三电极电化学系统测试了活性炭的电化学性质;考察了活化剂用量对活性炭电化学性质的影响。研究结果表明:活化过程中,随着碱含量的增加,活性炭的电化学性能逐渐提高。当碳碱比为1∶3时,活性炭的比表面积达到2572.7 m2/g;电流密度为1 A/g时,其质量比电容达到316 F/g。循环5000圈之后,比电容保持在95.7%,库仑效率保持在97.0%。采用两电极系统,进一步考察了活性炭的电化学性能,以1 mol/L Na₂SO₄为电解液,电压窗口拓宽至1.8 V,循环伏安曲线同样展现出良好的矩形,能量密度和功率密度分别为20.8 W·h/kg和230 W/kg。     

Hierarchical porous carbons with controlled micropores and mesopores for supercapacitor electrode materials

Various porous carbons were prepared by CO₂ activation of ordered mesoporous carbons and used as electrode materials for supercapacitor. The structures were characterized by using X-ray diffraction, transmission electron microscopy and nitrogen sorption at 77 K. The effects of CO₂ treatment on their pore structures were discussed. Compared to the pristine mesoporous carbons, the samples subjected to CO₂ treatment exhibited remarkable improvement in textural properties. The electrochemical measurement in 6 M KOH electrolyte showed that CO₂ activation leads to better capacitive performances. The carbon CS15A6, which was obtained after CO₂ treatment for 6 h at 950 °C using CMK-3 as the precursor, showed the best electrochemical behavior with a specific gravimetric capacitance of 223 F/g and volumetric capacitance of 54 F/cm³ at a scan rate of 2 mV/s and 73% retained ratio at 50 mV/s. The good capacitive behavior of CS15A6 may be attributed to the hierarchical pore structure (abundant micropores and interconnected mesopores with the size of 3-4 nm), high surface area (2749 m²/g), large pore volume (2.09 cm³/g), as well as well-balanced microporosity and mesoporosity.