商业化的锂离子电池石墨负极材料的研究进展

综述了锂离子电池石墨负极材料的研究进展,对MCMB、天然石墨与人造石墨、炭纤维为代表的石墨负极材料目前的研究和应用现状进行了详细的论述,并对石墨类炭负极的发展作了展望。     

文摘

<正>锂离子电池负极用纤维状炭材料[刊,中]/楠顶,黄正宏,康飞宇,等//新型炭材料,2015(1):1~11纤维状炭材料有各种尺度和形貌,由于成本和性能缺乏竞争力,制约其在锂离子电池负极材料中的应用。随着纳米技术的发展,一些改性后的新型炭纤维表现出良好的负极材料性能。文章综述了近年各种纤维状炭材料用作锂离子电池负极材料的国内外研究进展。依据纤维状炭材料的结构、性能及其研究思路,分别归纳了石墨纤维、炭纤维及具有各种     

锂离子二次电池炭负极材料

综述了锂离子二次电池用炭负极材料:石墨、各种体系炭纤维、石墨化中间相炭微球、焦炭、热解炭的结构与电性能等特点,并通过比较选择出最适宜的炭负极材料。     

世界规模最大的石油系炭纤维制造商

据日本工业新闻社报道：鹿岛石油集团采取新增设备的措施，扩大石油系沥青炭纤维的生产能力。其目的是为了适应短切纤维状炭纤维无纺布市场的需要及日益扩大的信息、通讯产业市场所急需的锂离子二次电池负极材料的需要。该公司至1998年8月，已投资30亿日元购置设备，用以增产850吨石油系沥青炭纤维。这些新增设备安装在该公司所属的茨城县鹿岛制油所内并已投入生产。这样，连同该公司原有的年产450吨的生产能力，年产可达1300吨石油系沥青炭纤维，并将成为当今世界最大规模的该类制品的制造商。世界规模最大的石油系炭纤维制造商@陆玉俊…     

煤基炭纳米纤维作为锂离子电池负极的研究

以强混酸处理的新疆黑山煤为部分碳源,通过静电纺丝法成功制备了具有丰富含氧官能团的柔性炭纤维(CCNFs).将该材料作为锂离子电池的自支撑负极,煤的加入量为0.5 g的炭纤维样品0.5-CCNFs展现出优异的循环稳定性,电池在电流密度为0.5 A·g-1下,循环1 000圈后,比容量高达524.1 mAh·g-1.在较大...     

螺旋纳米炭纤维的制备及其电化学性能

以乙炔为碳源,酒石酸铜为催化剂前躯体,氩气为保护气体,采用化学气相沉积法制备螺旋纳米炭纤维,通过扫描电镜观察不同温度下制备的螺旋纳米炭纤维的形貌;制备的螺旋纳米炭纤维作为锂离子电池负极材料,通过首次充放电、循环伏安、循环性能和交流阻抗谱测试电池的电化学性能。研究表明:在580℃下制备的螺旋纳米炭纤维管径均匀、螺旋化程度高,组装的电池具有最长的充放电平台,50次充放电循环后,库伦效率能保持在98.0%以上,比容量也保持在400 mA·h/g以上,循环伏安曲线重合性好,说明电化学性能稳定,电化学阻抗最小,导电性最好。螺旋纳米炭纤维纯度越高具有更好的电化学性能。     

由离子交换炭纤维和NaCl水溶液组成的二次电池

新二次电池约有2V的电动势,它是由离子交换炭纤维作正极和负极在NaCl水溶液中构成的。16g重的电极在放电制度为0.02A/dm~2的情况下,电池容量为0.46A-h。     

炭纤维吸波复合材料结构设计的研究进展

总结了炭纤维吸波性能的电磁改性方法,重点介绍了结构设计对炭纤维吸波复合材料吸波性能的影响,包括短切炭纤维、炭纤维排布结构、炭纤维电路模拟结构以及含炭纤维的混杂纤维排布对炭纤维复合材料吸波性能的影响.提出了炭纤维吸波复合材料今后的研究方向.     

聚丙烯腈(PAN)基炭纤维工业生产及应用

综述了炭纤维应用领域国内外市场,介绍炭纤维生产工艺过程及使用设备,指出当前国内炭纤维与国外产品的差距,并就当前我国炭纤维的发展现状给出了具体的应对措施,对发展我国炭纤维工业具有一定的指导意义。     

聚丙烯腈(PAN)基炭纤维工业生产及应用(续)

综述了炭纤维应用领域国内外市场,介绍炭纤维生产工艺过程及使用设备,指出当前国内炭纤维与国外产品的差距,并就当前我国炭纤维的发展现状给出了具体的应对措施,对发展我国炭纤维工业具有一定的指导意义。     

聚乙二醇对碳纤维电极材料性能的影响

以聚乙二醇为改性剂,采用静电纺丝法制备聚丙烯腈纤维。经预氧化、碳化过程制备了聚丙烯腈基碳纤维。用SEM、XRD等手段表征了碳纤维的微观形貌及结构。用XPS测试表征了碳纤维表面元素含量。用循环伏安测试法测试碳纤维电极材料的电化学性能。实验结果表明,当聚乙二醇加入量为4％时,得到的碳纤维电极材料电容性能最佳,其比电容值达到126．84F／g。     

活性炭纤维制备双电层电容器

研究了不同材料、比表面积和电解液对比电容的影响，不同比表面积，电解液对循环充电稳定性的影响。结果表明，作为制备双电层电容器的电极材料，活性炭纤维明显好于活性炭，同样基质的活性炭纤维，比表面积大的，比电容不一定大。     

碳材料在电双层电容器电极应用的最新研究

电容器与二次电池相比,有着显著的优点,尤其是高功率并能提供大电流的电双层（超级）电容器正是时代所需。对目前已用做电双层电容器电极材料的活性碳纤维、纳米碳管和膨胀性石墨的研究情况分别做了论述。与膨胀性石墨相比,如何发挥活性碳纤维和碳纳米管的实际电容效率是目前研究的重点。     

A study of the electrochemical behaviour of electrodes in operating solid-state supercapacitors

The electrochemical behaviour of electrodes and of complete solid-state supercapacitors has been studied by cyclic voltammetry (CV) and galvanostatic charge/discharge (CD) measurements using two independent electrochemical equipments. The first one controlled the execution of the test and recorded the voltage and current values of the complete supercapacitor while the other one recorded the potential changes of the single electrodes. In this work, two different types of capacitors were studied: (a) a symmetric supercapacitor using carbon electrodes, and (b) a hybrid (asymmetric) supercapacitor with ruthenium oxide/carbon in the positive electrode and carbon in the negative electrode. The studies evidenced that in the symmetric capacitors the positive electrode controlled the capacitive performance and an optimal mass ratio from 1.2:1 to 1.3:1 between the positive and the negative electrodes was found in the investigated conditions. For the hybrid supercapacitor it was observed that the ruthenium-based positive electrode influenced the capacitive performance of carbon-based negative electrode and that an accurate balance of carbon loading in the negative electrode was necessary.     

Preparation of carbon micro-coils involving the decomposition of hydrocarbons using PACT (plasma and catalyst technology) reactor

Carbon micro-coils as well as carbon fibers with various morphologies were prepared by the decomposition of hydrocarbons, such as acetylene, methane, propane, ethylene, etc., at 770°C using a PACT (plasma and catalyst technology) reactor. The preparation conditions, growth mechanism and morphology of the carbon micro-coils were examined. The Ni electrode of the PACT reactor was used as the catalyst as well as a plasma source electrode. It was found that hydrocarbons, such as methane, propane and ethylene, decomposed under the plasma and catalyst atmosphere to form acetylene as the main decomposition product, and then this acetylene was further decomposed to form carbon micro-coils. Using a Ni powder catalyst dispersed on the substrate, the carbon micro-coils with a double helix structure, in which two pieces of carbon coils entwine each other in the same coiling direction, grew among the single straight carbon fibers and paired straight fibers. On the other hand, the carbon micro-coils with a single helix structure and wide coil pitch were obtained by the indirect decomposition of acetylene using the N₂ plasma formed by the PACT reactor.     

Effect of activation on the carbon fibers from phenol–formaldehyde resins for electrochemical supercapacitors

Activated carbon fibers (ACF) are prepared from phenol–formaldehyde resin fibers through chemical activation and physical activation methods. The chemical activation process consisted of KOH, whereas the physical activation was performed by activation in CO₂. The characteristics of the electrochemical supercapacitors with carbon fibers without activation (CF), carbon fibers activated by CO₂ (ACF-CO₂), and carbon fibers activated by KOH (ACF-KOH) have been compared. The activated carbon fibers from phenol–formaldehyde resins present a broader potential range in aqueous electrolytes than activated carbon and other carbon fibers. Activation does not produce any important change in the shape of starting fibers. However, activation leads to surface roughness and larger surface areas as well as an adapted pore size distribution. The higher surface areas of fibers treated by KOH exhibited higher specific capacitances (214 and 116 F g⁻¹ in aqueous and organic electrolytes, respectively) and good rate capability. Results of this study suggest that the activated carbon fiber prepared by chemical activation is a suitable electrode material for high performance electrochemical supercapacitors.     

木质素纳米颗粒/天然纤维基活性碳纤维材料的制备及其电化学性能

以木质素纳米颗粒（LNPs）负载的天然纤维复合材料为研究对象,利用KOH活化的方法对其进行处理制备生物质基复合多孔活性碳纤维电极材料。随后在三电极体系中对合成的复合多孔活性碳纤维电极材料进行了电化学性能测试。研究表明,在0.5A/g的电流密度下,KOH活化的复合碳纤维电极材料的比电容为351.13F/g,远高于相同条件下未活化的复合碳纤维电极材料的比电容（7.88F/g）和未负载LNPs的天然纤维基活性碳纤维材料（306.50F/g）。而且在活化过程中,负载在纤维表面的LNPs会形成多孔的活性碳层结构,这会进一步提高复合活性碳纤维材料的循环稳定性,同时LNPs中丰富的羟基赋予复合材料额外的赝电容。在10A/g的电流密度下经过10000次循环后,复合活性碳纤维电极材料的电容保持率仍然为95%,高于未负载LNPs的活性碳纤维电极材料的电容保持率87%。结果表明,木质素纳米颗粒/天然纤维基活性碳纤维材料是一种理想的电极材料,本研究也为LNPs在生物质碳纤维作为储能电极材料的高值化应用提供了一条新途径。     

A study of nitroxide polyradical/activated carbon composite as the positive electrode material for electrochemical hybrid capacitor

We present a new concept of the hybrid electrochemical capacitor technology in which a poly(2,2,6,6-tetramethylpiperidinyloxy methacrylate) nitroxide polyradical/activated carbon composite (PTMA-AC) is used as the positive electrode material and activated carbon is used as the negative electrode material. On the positive electrode, both reversible reduction and oxidation of nitroxide polyradical and non-faradic ion sorption/de-sorption of activated carbon are involved during charge and discharge process. The capacity of the composite electrode is 30% larger than that of the pure activated carbon electrode. A hybrid capacitor fabricated by the PTMA-AC composite positive electrode and the activated carbon negative electrode shows a good cycling life, it can be charged/discharged for over 1000 cycles with slight capacity loss. The hybrid capacitor also has a good rate capability, it maintains 80% of the initial capacity even at the high discharge current of up to 20C.     

Piezoelectric Fibers with Uniform Internal Electrode by Co-Extrusion Process

Piezoelectric fibers with internal electrodes were fabricated by the co-extrusion process. The initial feedrods, which were composed of an outer piezoelectric PZN–PZT layer, a thin conducting PZN–PZT/Ag layer inside, and fugitive carbon black at the center, were co-extruded through a reduction die (1 mm) to form a continuous fiber. After thermal treatment and sintering, the PZN–PZT/Ag layer became the inner electrode, while the carbon black at the center was removed by oxidation to form an empty space. Three different types of fibers were produced: (i) solid fiber filled with an inner electrode, (ii) hollow fiber clad with a uniform inner electrode, and (iii) hollow fiber clad with a partial inner electrode. The piezoelectric properties of the fibers were evaluated in terms of their longitudinal strain (s₃₁) or transverse displacement. When the dimensions of the fiber were 840 μm (outer diameter) × 420 μm (inner diameter) × 40 mm (length), the longitudinal strains of the solid fiber with the inner electrode and hollow fiber clad with the uniform inner electrode were 5.25 × 10⁻⁵ and 8.5 × 10⁻⁵ m/m, respectively, under an applied voltage of 100 V (0.48 kV/mm) at a frequency of 100 Hz. For the hollow fiber clad with a partial inner electrode with the same dimensions, the transverse displacement was 80 μm under the same applied electric field.     

Preparation and characterization of ultrafine electrospun polyacrylonitrile fibers and their subsequent pyrolysis to carbon fibers

The present contribution reports the fabrication and characterization of ultrafine polyacrylonitrile (PAN) fibers by electrospinning and further development of the as‐spun PAN fibers into ultrafine carbon fibers. The effects of solution conditions (i.e., solution concentration, viscosity, conductivity, and surface tension) and process parameters (i.e., applied electrostatic field strength, emitting electrode polarity, nozzle diameter, and take‐up speed of a rotating‐drum collector) on morphological appearance and average diameter of the as‐spun PAN fibers were investigated by optical scanning (OS) and scanning electron microscopy (SEM). The concentration, and hence the viscosity, of the spinning solutions significantly affected the morphology and diameters of the as‐spun PAN fibers. The applied electrostatic field strength and nozzle diameter slightly affected the diameters of the as‐spun fibers, while the emitting electrode polarity did not show any influence over the morphology and size of the as‐spun fibers. Utilization of the rotating‐drum collector enhanced the alignment of the as‐spun fibers. Within the investigated concentration range, the average diameter of the fibers ranged between 80 and 725 nm. Finally, heat treatment of the as‐spun fibers with their average diameter of about 450 nm was carried out at 230 and 1000 °C, respectively. Various characterization techniques revealed successful conversion into carbon fibers with an average diameter of about 250 nm. Copyright © 2006 Society of Chemical Industry