锂离子电池用硅/石墨/碳复合负极材料的电化学性能

采用湿法混料及高温热解法制备了锂离子电池用硅/石墨/碳复合负极材料,并研究了不同配方的复合材料结构及电化学性能。研究发现,硅含量为20%(质量分数)时,复合材料首次可逆容量为865mAh/g,循环30次后仍为757mAh/g,容量保持率可达88%,大大改善了硅基材料作为锂离子电池负极材料的电化学性能。     

Amphiphilic carbonaceous material modified graphite as anode material for lithium-ion batteries

Artificial graphite powder was coated by amphiphilic carbonaceous material (ACM) in aqueous solutions. SEM and XRD results show that the surface defects and edge sites of original graphite are uniformly covered by the ACM coating layer after modification. The overall characteristics of graphite, however, are not severely changed. Electrochemical measurements were then carried out to evaluate the anode performances of samples in lithium-ion batteries. The modified graphite shows an initial efficiency up to 90.6% and discharge capacitance of 366.4 mAhg^− 1. Meanwhile, its capacitance remains as high as 350 mAhg^− 1 after 30 cycles charge/discharge tests, evincing good cyclic performance. Compared with conventional methods, the abovementioned non-organic solvent coating presents an economic, facile, and green pathway for graphite mass utilisation as an alternative anode material in lithium-ion batteries.     

Si/C particles on graphene sheet as stable anode for lithium-ion batteries

Silicon is considered as one of the most promising anodes for Li-ion batteries (LIBs),but it is limited for commercial applications by the critical issue of large volume expansion during the lithiation.In this work,the structure of silicon/carbon (Si/C) particles on graphene sheets (Si/C-G) was obtained to solve the issue by using the void space of Si/C particles and graphene.Si/C-G material was from Si/PDA-GO that silicon particles was coated by polydopamine (PDA) and reacted with oxide graphene (GO).The Si/C-G material have good cycling performance as the stability of the structure during the lithiation/dislithiation.The Si/C-G anode materials exhibited high reversible capacity of 1910.5 mA h g-1 and 1196.1 mA h g-1 after 700 cycles at 357.9 mA g-1,and have good rate property of 507.2 mA h g-1 at high current density,showing significantly improved commercial viability of silicon electrodes in high-energy-density LIBs.     

Porous Si/Cu6Sn5/C composite containing native oxides as anode material for lithium-ion batteries

Journal of Materials Science: Materials in Electronics - Porous Si/Cu6Sn5/C composite containing native oxides was prepared via solid-state mechanical milling and wet chemical etching. This...     

锂离子电池用酚醛树脂热解碳负极材料的研究进展

简要介绍了锂离子电池负极材料的种类,硬碳材料的结构特点、突出的优异性能.重点总结了酚醛树脂热解硬碳负极材料与掺杂和包覆型酚醛树脂热解硬碳负极材料的国内外研究进展情况,并提出了展望.     

多孔硅/硅钛合金的制备及在锂离子电池负极上的应用

以钛掺杂介孔二氧化硅SBA-15为前驱体,用镁热还原法制备多孔硅/硅钛合金复合材料。采用X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)和红外光谱(FT-IR)等方法对复合材料进行表征;利用恒电流充放电对复合材料作为锂离子电池负极材料的电化学性能进行分析。结果表明,多孔结构为体积膨胀提供了缓冲空间,硅钛合金的存在起到支撑骨架的作用,同时一定程度上改善了负极材料的导电性,多孔硅/硅钛合金复合材料具有较好的循环稳定性,0.1C循环50圈后可逆容量为801mAh/g,倍率性能也较单质硅材料大大提高,1C倍率下放电容量为618.9mAh/g。     

Nickel-cobalt oxides/carbon nanoflakes as anode materials for lithium-ion batteries

Novel nickel-cobalt oxides/carbon nanoflakes with Ni/Co molar ratio = 1:1 and 1:2 have been synthesized by a convenient hydrothermal method followed by a simple calcination process. X-ray diffraction results showed that the composites were composed of NiO, Co₃O₄, and carbon. Scanning electron microscope measurements demonstrated that the composites were flakes less than 100 nm in thickness, and the corresponding energy dispersive spectroscopy mapping showed that the carbon was distributed homogeneously in the composites. The electrochemical results showed that the composite electrodes exhibited low initial coulombic efficiency and excellent charge-discharge cycling stability. Additionally, the effect of different Ni/Co molar ratios on the electrochemical properties of the composites was investigated, and better performance was obtained for the sample with a Ni/Co molar ratio of 1:2.     

Cathodic titania nanotube arrays as anode material for lithium-ion batteries

The titanium dioxide nanotube arrays (TNAs) have been synthesized at cathode and anode via standard electrochemical method for their subsequent use as anode material for lithium-ion batteries (LIBs). The TNAs fabricated at cathode have higher Ti³⁺ in comparison to TNAs at anode, which was confirmed using X-ray photoelectron spectroscopy and Raman spectrometry. Moreover, the lattice parameters of cathodic TNAs are estimated via Rietveld refinement of X-ray diffraction, which also conform to Ti³⁺ doping and insertion of protons (H⁺). The electrochemical impedance spectroscopy hints an increment in the electronic conductivity of TNAs fabricated at cathode. As a result, high reversible areal–specific capacity (~385.5 µAh cm^?2 at 100 µA cm^?2) with excellent rate capability is acquired by utilizing TNAs fabricated at cathode as anode material in LIBs.     

Silicon nanowire array films as advanced anode materials for lithium-ion batteries

Silicon nanowire array films were prepared by metal catalytic etching method and applied as anode materials for rechargeable lithium-ion batteries. The films completely consisted of silicon nanowires that were single crystals. Aluminum films were plated on the backs of the silicon nanowire films and then annealed in an argon atmosphere to improve electronic contact and conduction. In addition to easy preparation and low cost, the silicon nanowire film electrodes exhibited large lithium storage capacity and good cycling performance. The first discharge and charge capacities were 3653 mAh g⁻¹ and 2409 mAh g⁻¹, respectively, at a rate of 150 mA g⁻¹ between 2 and 0.02 V. A stable reversible capacity of about 1000 mAh g⁻¹ was maintained after 30 cycles. The good properties were ascribed to the silicon nanowires which better accommodated the large volume change during lithium-ion intercalation and de-intercalation.     

Pineapple leaf fibers (PALF) as the sustainable carbon anode material for lithium-ion batteries

Journal of Materials Science: Materials in Electronics - Pineapple leaf fiber (PALF) is considered as a promising low cost carbon precursor to produce a high graphitic carbon material, regarding to...     

Enhanced cycling performance of nanocrystalline Fe3O4/C as anode material for lithium-ion batteries

Fe3O4-carbon composite was prepared by the sol-gel method. The crystal structure, morphology, and phases present in the product were investigated by X-ray diffraction and by scanning electron microscopy (SEM) combined with energy dispersive X-ray spectroscopy and field-emission SEM. Electrochemical characterization was performed using constant current charge-discharge testing and electrochemical impedance spectroscopy. The Fe3O4/C electrode has high initial columbic efficiency (87%) and outstanding cycling performance (775.3 mAh g(-1) after 90 cycles at a current density of 100 mA g(-1)).     

Electrochemical properties of Super P carbon black as an anode active material for lithium-ion batteries

A new approach to investigate upon the electrochemical properties of Super P carbon black anode material is attempted and compared with conventional mesophase pitch-based carbon fibers (MPCFs) anode material for lithium-ion batteries. The prepared Super P carbon black electrodes are characterized using transmission electron microscope (TEM). The assembled 2032-type coin cells are electrochemically characterized by ac impedance spectroscopic and cyclic voltammetric methods. The electrochemical performance of charge and discharge was analyzed using a battery cycler at 0.1 C rate and cut-off potentials of 1.20 and 0.01 V vs. Li/Li⁺. The electrochemical test illustrates that the discharge capacity corresponding to Li intercalation into the Super P carbon black electrode is higher and coulombic efficiency is maintained approximately 84% at the end of the 20th cycling at room temperature.     

Structure and electrochemical performance of ZnO/CNT composite as anode material for lithium-ion batteries

Metal oxides are well-known potential alternatives to graphite as anode materials of lithium-ion batteries, and they can deliver much higher reversible capacities than graphite even at high current densities. In this study, hexagonal disk-shaped ZnO are synthesized by a facile solution reaction of ZnCl₂ and its composite is prepared in the presence of carbon nanotubes (CNTs). The as prepared ZnO/CNT composite has been characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, fourier transform-infrared spectroscopy and Rutherford backscattering spectroscopy. Electrochemical characterization by cyclic voltammetry, electrochemical impedance spectroscopy, and galvanostatic discharge/charge tests demonstrate that the conversion reactions in ZnO and ZnO/CNT electrodes enable reversible capacity of 478 and 602 mAh g^?1, respectively for up to 50 cycles. Our investigation highlights the importance of anchoring of small ZnO particles on CNTs for maximum utilization of electrochemically active ZnO and CNTs for energy storage application in lithium-ion batteries.     

Synthesis and characterization of SnO-carbon nanotube composite as anode material for lithium-ion batteries

SnO-carbon nanotube composite was synthesized by a sol-gel method. The electrochemical behavior of the composite using an anode active material in lithium-ion batteries was investigated. It was found that the composite showed enhanced anode performance compared with the unsupported SnO or carbon nanotube (CNT). The capacity fade of the composite electrode was reduced over unsupported SnO or CNT. We attribute the results to the conductivity and ductility of the CNT matrix, and the high dispersion of SnO.     

碳包覆空心Fe3O4纳米粒子作为锂离子电池负极材料的电化学性能研究

以二茂铁为铁源,石油渣油为碳源,通过加压热解和空气氧化制备了碳包覆空心Fe3O4纳米粒子。采用X射线衍射(XRD)、透射电镜(TEM)以及高倍透射电镜(HRTEM)等测试方法对样品的形貌和结构进行表征。采用恒流充放电和交流阻抗方法测试碳包覆空心Fe3O4纳米粒子作为锂离子电池负极材料的电化学性能。在电流密度为0.2mA/cm2时,首次放电比容量高达1294.7mAh/g,30次循环之后其放电比容量为392.1mAh/g;电流密度为1mA/cm2时,首次放电比容量为216.3mAh/g,30次循环之后其放电比容量为113mAh/g。     

Synthesis and characterization of Sb/CNT and Bi/CNT composites as anode materials for lithium-ion batteries

Sb/CNT and Bi/CNT composites were prepared by a heating treatment method. SEM imaging showed that the metal particles were uniformly deposited on the CNTs exterior and in the CNTs web. It was found that the composites showed improved cyclability than unsupported Sb and Bi and higher reversible capacities than CNTs. The improvement may be attributed to the small-scale dimension and high dispersion of the metal particles and the conductivity and ductility of the CNTs matrix. Moreover, the first reversibility was also increased comparing to CNTs, resulted from the lower surface of the composites.     

Facile preparation of TiO2/C nanocomposites as anode materials for lithium-ion batteries

TiO₂/C nanospheres with diameter of 300–400 nm were synthesized by controlled thermal decomposition of titanium glycolate spheres in inert atmosphere. The effect of the calcination temperature and atmosphere on the structure and composition of the product are investigated. The products obtained by calcination of the precursor in nitrogen at 500°C consist of anatase and rutile nanoparticles, and amorphous carbon that is in situ generated from the organic components of glycolate precursor. When used as anode material for lithium-ion batteries, the as-prepared TiO₂/C nanocomposite delivers a capacity of 166 mAh/g after 250 charge/discharge cycles at a current rate of 0.2 C and give a good rate capability. The native carbon not only improves the local conductivity but also prevents the aggregation and growth of TiO₂ nanoparticles during calcination, allowing efficient electronic conductivity and Li ion diffusion.     

鳞片石墨取向对鳞片石墨/聚丙烯、鳞片石墨/尼龙66复合材料导热性能的影响

为了研究鳞片石墨在基体中的取向对复合材料导热性能特别是不同方向导热性能的影响,通过双螺杆挤出混合及注射成型制备了鳞片石墨/聚丙烯（PP）、鳞片石墨/尼龙66（PA66）导热复合材料,并利用扫描电子显微镜和超声波测试对制备的样品进行了分析。结果表明：鳞片石墨的粒径越小,平面取向度越高,平面与垂直方向的热导率差值越大。加工中双螺杆挤出机的过度剪切会破坏鳞片石墨的片层结构,影响鳞片石墨导热网络的形成,降低复合材料的热导率,但提高了材料导热的各向均匀性。适度的剪切可以打开鳞片石墨的片层结构,提高复合材料的热导率,注射成型更多影响到制品导热的各向异性。     

Two-dimensional metallic BP as anode material for lithium-ion and sodium-ion batteries with unprecedented performance

Improving the storage capacities of electrode materials is one of the most critical points for ion batteries. Two-dimensional (2D) topological semimetals with high carrier mobility are naturally suitable as electrode materials. Herein, using the first-principle calculations, 2D BP monolayer with Dirac-type band structure is predicted to be a superior anode material with ultrahigh capacity for both Li/Na-ion batteries. The BP monolayer remains metallic after the adsorption of Li/Na ions, ensuring a good conductivity. Furthermore, BP owns low diffusion barriers (0.35 eV for Li ions and 0.16 eV for Na ions) and a moderate lattice change (3%) during the process of charging and discharging. Remarkably, the storage capacity of monolayer BP is enhanced to 1924 mAh/g by multilayer adsorption of both Li/Na ions, much higher than those of most previous 2D anode materials. All these characteristics strongly suggest that BP has great potential as a superior anode material in Li/Na-ion batteries.