竹基碳纤维/MoS2锂离子电池负极材料

随着电子产品、电动汽车以及智能电网的快速发展,不仅需要锂离子电池(LIBs)具有优异的储锂性能,而且要求电极材料成本低廉、资源丰富和绿色环保。基于碳负极材料的优点,将废弃的一次性竹筷,在碱性溶液中经过可控的热处理,利用竹子中丰富的天然纤维素,从而获得尺寸均匀的碳纤维(CFs)材料。相比于石墨电极,竹基CFs作为LIBs的负极材料时表现出优异的电化学性能。为进一步提高其储锂性能,以CFs为骨架,通过水热法在其表面制备了一层二硫化钼(MoS₂)纳米花,形成核壳结构的CFs/MoS₂复合电极材料。电化学测试结果表明,CFs电极在200 mA/g的电流密度下循环500次,放电比容量仍有381.1 mA·h/g;CFs/MoS₂复合材料在1 000 mA/g的大电流密度下经过1 000次循环,仍保持有843 mA·h/g的放电比容量。     

CoFe2O4@C复合纳米纤维膜作为自支撑锂离子电池负极

为了提高CoFe₂O₄作为锂离子电池负极材料的综合电化学性能,将其与高导电性的碳纤维进行复合。通过静电纺丝及低温碳化制备了均匀镶嵌CoFe₂O₄纳米颗粒的碳纳米纤维(CoFe₂O₄@CNFs)柔性复合膜,使用XRD、TG、Raman、SEM、TEM、CV、GCD和EIS等对复合物进行表征,着重研究了CoFe₂O₄含量对其储锂性能的影响。该复合膜直接用作自支撑锂离子电池负极时表现出较好的电化学性能。CoFe₂O₄的引入显著提高了碳纳米纤维膜的电化学性能,随着CoFe₂O₄含量的增加,CoFe₂O₄@CNFs电极的比容量先增加后减小,CoFe₂O₄含量约为33.3%(w/w)的CoFe₂O₄@CNFs...     

高性能自支撑CuS/SnS2锂电池负极材料

过渡金属硫化物作为锂电池负极材料具有极高比容量,但其制备的电极普遍存在导电性差、体积变化大等问题,本研究设计了一种新型的自支撑CuS/SnS₂镂空片状锂电池负极材料,以导电碳布作为基底,生长包覆CuS/SnS₂镂空纳米片,具备特殊的纳米包覆结构及双金属协同效应,使其在保持较高比容量的同时具备良好的循环稳定性,整体电化学性能优异。研究不同Cu/Sn含量对CuS/SnS₂负极材料电化学性能的影响,最佳配比的CuS/SnS₂负极材料在0.2 A·g?1电流密度下循环50次后比容量为1480 mAh·g?1,库伦效率稳定在99.5%,在2 A·g?1电流密度下循环200次后比容量仍能保持在697 mAh·g?1,库伦效率为99.8%。      

碳布基自支撑锂/钠离子电池负极材料的研究进展

随着可卷曲、可折叠、可穿戴及植入式柔性电子设备的出现,柔性自支撑电极材料的研究也备受瞩目。碳布是一种商用机织物,由于其高导电性、多孔网络、大表面积、良好的机械柔韧性和强度,被认为是构建柔性电极的优秀基材。近年来,各种活性物质(如金属单质、金属化合物及其复合物)直接生长或涂敷在碳布表面,当用作锂/钠离子电池负极时,它们表现出优异的机械稳定性和电化学性能。本文综述了这几类碳布基自支撑锂/钠离子电池负极材料的研究现状,重点介绍了碳布基自支撑锂/钠离子电池负极材料中的三个关键问题,具体包括碳布的预活化、活性物质在碳布上的负载形貌及电化学性能的表征,并展望了碳布基自支撑锂/钠离子电池负极材料所面临的挑战和机遇,这对于碳布用作锂/钠离子电池自支撑电极材料基底的研究具有一定的指导意义。     

锂离子电池SiO2负极材料的改性研究进展

SiO₂因理论比容量高(1 965 mAh·g^-1)、循环稳定性好、丰度高和低成本等特点,被认为是一种具有前景的绿色锂离子负极材料。实际上当SiO₂作为锂电池的负极材料时,由于其Si-O之间的键能大,对Li⁺表现出惰性而没有展现出良好的电化学性能。然而,通过对它进行表面修饰或构造3D纳米结构,则表现出对锂的活性。为了进一步了解这一负极材料,综述了SiO₂作为锂离子负极材料的锂化反应机理,并从尺寸大小、结构、与金属氧化物复合以及表面改性等方面讨论其电化学性能。最后,提出了SiO₂作为负极材料的挑战和工作展望。     

锂离子电池硅/碳纳米管/石墨烯自支撑负极材料研究

通过真空驱动自组装法及蒸汽处理得到结构疏松的硅/碳纳米管/石墨烯自支撑负极材料(Si/CNTs/GP)。纳米硅颗粒(50 nm)为活性物质, 均匀分布在石墨烯片层结构中间; 石墨烯作为碳基体, 通过自组装构筑形成二维导电网络; 碳纳米管(CNTs)具有超高导电性和良好的力学强度, 它通过吸附作用均匀分布在石墨烯基体上形成导电的支撑网络结构。经过蒸汽处理后, 石墨烯层间距明显增大, 层与层之间不再是紧密堆叠的结构, 而是形成一种疏松、褶皱、内部空隙丰富的片层结构。Si/CNTs/GP负极材料中丰富的内部空穴和贯穿孔洞, 提供了材料很高的比表面积, 能有效提高电解液对材料的浸润性, 极大缩短了离子传输距离。同时这些内部空穴也有效缓冲硅充放电时的体积膨胀, 提高了材料的结构稳定性和电化学性能。该负极材料在4 A/g的大电流密度下容量维持在600 mAh/g, 表现出良好的大电流循环稳定性能。     

类石墨烯二硫化钼在锂离子电池负极材料中的研究进展

综述了近年来国内外应用于锂离子电池负极材料的类石墨烯MoS2基材料的研究进展。简要介绍了其晶体结构、制备方法、嵌锂反应机理,并详细介绍了2H-MoS2基材料在锂离子电池负极领域的研究进展,包括水热法、硬模板法和溶剂热法制备特殊形貌的2H-MoS2,以及无定形碳、介孔碳分子筛、碳纳米管、石墨烯/2H-MoS2复合材料及高分子聚合物/C/2H-MoS2复合材料的最新研究现状。     

锂离子电池负极材料的研究进展

锂离子电池因其质量轻、能量密度较高，迎合了家用电器和通讯设备向小型化、微型化方向发展的需要．锂离子电池能够成功应用的关键在于嵌入与脱出可逆的锂离子负极材料的制备．因此，对负极材料的研究非常重要．主要介绍了锂离子电池的电化学反应原理、一般特性及电池负极材料的最新研究进展．其中，对最新的负极材料——纳米碳管及其它负极材料的研究情况，进行了深入的阐述和分析，同时，也提出了各种负极材料在研究中存在的问题及今后的发展前景．     

锂离子电池负极材料研究进展

锂离子电池(LIB)因其无记忆效应、环境友好且自放电小等各项优异性能得到了相关研究者的重点关注.信息电子产品、电动汽车和智能电网的发展对高能量密度、长循环寿命和低成本的LIB产生了巨大需求.负极作为LIB的重要组成部分之一,其性能对电池整体的各项指标有重要影响,要求负极所应用的材料具有高比容量和优异的循环性能等特性.传...     

锂离子电池氧化物负极材料的研究进展

综述了锂离子电池氧化物负极材料的研究进展,介绍了各材料的储锂机理、一般特点及最新研究成果.其中,对研究比较多的锡基氧化物材料及纳米材料进行了深入阐述.同时,探讨了氧化物负极材料目前存在的问题及解决的办法,对该类材料的发展趋势进行了展望.     

Synthesis of polycrystalline SnO2 nanotubes on carbon nanotube template for anode material of lithium-ion battery

Polycrystalline tin oxide nanotubes have been prepared by a layer-by-layer technique on carbon nanotubes template. Firstly, the surface of carbon nanotubes was modified by polyelectrolyte. Then, a uniform layer of tin oxide nanoparticles was formed on the positive charged surface of carbon nanotubes via a redox process. At last, the polycrystalline tin oxide nanotubes were synthesized after calcination at 650 °C in air for 3 h. The as-synthesized polycrystalline nanotubes with large surface area exhibit finer lithium storage capacity and cycling performance, which shows the potentially interesting application in lithium-ion battery.     

Facile synthesis and electrochemical properties of porous SnO2 micro-tubes as anode material for lithium-ion battery

Porous SnO₂ micro-tubes were synthesized by the thermal decomposition of SnC₂O₄ precursor. The morphology of SnC₂O₄ could be preserved after the controlled heat treatment and a lot of mesopores left due to the release of gases. The mesoporous nature with a range of 3-50 nm was characterized by BET method. SEM images showed that the obtained SnO₂ samples were rhombic tube-like with swallow-tailed nozzles. When the porous SnO₂ micro-tubes were used as anode materials for lithium-ion battery, they exhibited high lithium storage capacity and coulomb efficiency. In addition, CV results demonstrated that the formation of Li₂O at high voltage was partially reversible reactions.     

锂离子电池富锂正极材料Li[Li0.2Ni0.16Mn0.56Co0.06Al0.02]O2的合成和电化学性能

用溶胶-凝胶法首次合成了富锂正极材料Li[Li0.2Ni0.16Mn0.56Co0.06Al0.02]O2,它可以看成是Li[Li1/3Mn2/3]O2和LiNi0.4Mn0.4Co0.15Al0.05O2形成的固溶体。XRD测试表明该材料具有ɑ-NaFeO2层状结构,用SEM观察材料粒径为100nm左右。充放电测试得到,材料在2～4.8V范围内,0.1C的电流下,20℃时,首次放电比容量达221.8mAh/g,库伦效率为85.3%;55℃时,首次放电比容量达281.7mAh/g,库伦效率为93.0%;且该材料具有很好的循环稳定性及优良的倍率性能。通过循环伏安测试分析了该材料的充放电机理。     

Electrochemical properties of carbon-coated TiO2 nanotubes as a lithium battery anode material

To use as an anode material of lithium batteries, carbon-coated TiO₂ nanotubes are prepared by hydrothermal reaction of rutile particles, subsequent sol–gel mixing with poly(vinyl pyrrolidone), and heat treatment at 300–500 °C. The carbon-coated TiO₂ nanotubes are also characterized by morphology observation, crystalline property analysis, potentiostatic redox behaviors, and galvanostatic discharge–charge evaluations at low and high rates. When annealed at 300 °C, the amorphous phase of carbon layers which are covered on the TiO₂ nanotubes dominates the anatase TiO₂ nanocrystalline phase. When annealed at 500 °C, the carbon-coated TiO₂ nanotubes exhibit superior cyclic performance and high-rate capability, due to the crystalline phase in the carbon-coated layer formed by annealing at high temperature.     

Structure and electrochemical performance of Fe3O4/graphene nanocomposite as anode material for lithium-ion batteries

Using hydrothermal method, Fe₃O₄/graphene nanocomposite is prepared by synthesizing Fe₃O₄ particles in graphene. The synthesized Fe₃O₄ is nano-sized sphere particles (100–200 nm) and uniformly distributed on the planes of graphene. Fe₃O₄/graphene nanocomposite as anode material for lithium ion batteries shows high reversible specific capacity of 771 mAh g⁻¹ at 50th cycle and good rate capability. The excellent electrochemical performance of the nanocomposite can be attributed to the high surface area and good electronic conductivity of graphene. Due to the high surface area, graphene can prevent Fe₃O₄ nanoparticles from aggregating and provide enough space to buffer the volume change during the Li insertion/extraction processes in Fe₃O₄ nanoparticles.     

A novel anode material of Fe2VO4 for high power Lithium ion battery

Spinel Fe₂VO₄ was synthesized by solid state method and its properties were characterized using XRD, SEM, TG-DSC and specific surface area measurements. The average size of the particles was 500 nm. TG-DSC test demonstrated that the Fe₂VO₄ was thermally stable in nitrogen atmosphere within 300 °C. Lithium insertion into the sample at room temperature and 55 °C has been investigated and the highest discharge capacity approached 250 mAh/g at an average voltage of 0.6 V vs Li⁺/Li. Capacity retention was unexpectedly good at 1C discharge rate at room temperature and 55 °C. At 5C discharge rate, the specific capacity was still 136 mAh/g. The results show that the Fe₂VO₄ is a promising anode material due to its high specific capacity, thermal stability and rate performances.     

Preparation of Mn2SnO4 nanoparticles as the anode material for lithium secondary battery

The ultrafine Mn₂SnO₄ nanoparticles with diameters of 5-10 nm have been prepared by thermal decomposition of precursor MnSn(OH)₆. The MnSn(OH)₆ nanoparticles precursor was synthesized by a hydrothermal microemulsion method. X-ray diffraction, transmission electron microscopy, high-resolution transmission electron microscopy and electron diffraction have been employed to characterize the crystal structures and morphologies of the as-prepared samples. High-resolution transmission electron microscopy observations revealed that the as-synthesized nanoparticles were single crystals. The thermal characterization was studied by differential thermal analysis and thermogravimetry analysis measurements. Electrochemical test showed that the Mn₂SnO₄ nanoparticles exhibited a high initial charge-discharge capacity of 1320 mAh/g.     

锂离子电池正极材料热稳定性研究进展

对常见正极材料的热稳定性进行了综述,通过对正极材料的DSC数据的比较,可见表面包覆可以提高正极材料的热稳定性,原因是包覆材料能有效抑制活性材料和电解液的直接接触,减少热量的产生,提高电池的安全性.     

Li3SbO4: A new high rate anode material for lithium-ion batteries

Electrochemical properties of Li₃SbO₄ have been investigated as an anode in lithium-ion coin cells. X-ray powder diffraction of the material, synthesized by the conventional solid state technique with thermal treatment at 800 °C in air, confirmed a monoclinic structure with lattice parameters of a = 5.159 Å, b = 6.048 Å, c = 5.144 Å and β = 109°. Electrochemical measurements in 2032 type coin cells show that Li insertion and extraction in this material take place at 0.72 and 1.05 V vs Li/Li⁺ respectively. Although the material shows a low average reversible capacity of 81 mAhg⁻¹ at a current density of 0.05 mAcm⁻² (C/5), an excellent rate performance with nearly 100% Coulombic efficiency has been observed. Continuous cycling up to 200 cycles at current densities of 0.05, 4.0 and 8.0 mAcm⁻² shows that by increasing the current rate from C/5 to 43 C i.e. 215 times, the average reversible capacity decreases only 10%. Thus, the material might be very useful for applications requiring high rate of charge and discharge.     

TiB2 and TiC stainless steel matrix composites

Stainless steel matrix composites reinforced with TiB₂ or TiC particulates have been in situ produced through the reactive sintering of Ti, C and FeB. X-ray diffraction analysis confirmed the completion of reaction. The TiB₂, TiC and steel were detected by X-ray diffraction analysis. No other reaction product or boride was found, indicating the stability of TiB₂ and TiC in steel matrix. The SEM micrographs revealed the morphology and distribution of in situ synthesized TiB₂ and TiC reinforcements in steel matrix. During sintering the reinforcements TiB₂ and TiC grew in different shapes. TiB₂ grew in hexagonal prismatic and rectangular shape and TiC in spherical shape.