锂硫电池三维石墨烯/硫复合正极材料的制备及其性能

以天然石墨粉为原料,采用改进的Hummers法制备氧化石墨烯,再通过水热还原、熔融升华法制备得到三维石墨烯/硫二元复合正极材料。对三维石墨烯/硫复合正极材料进行微观形貌和电化学性能的表征,结果显示:石墨烯具有三维多孔网状结构,能有效增加活性物质硫的利用率,并且硫均匀地负载在三维石墨烯的孔道和表面,没有发生团聚现象;电化学性能结果显示:三维石墨烯/硫复合正极材料在C/8电流密度下首次充放电容量为800mAh/g,40周次循环后容量还保持在600mAh/g左右,表明三维石墨烯/硫复合正极材料具有优异的循环与倍率性能。     

碳包覆的磷/石墨烯复合材料的制备及其储锂性能研究

以纳米黑磷和氧化石墨烯为原料,通过高温热处理的方法合成了碳包覆的磷/石墨烯复合材料,通过XRD、Raman、FT-IR、XPS及SEM对该复合材料进行表征。电化学性能测试表明,在100mA/g的电流密度下,制备的复合材料首次充电比容量为530mAh/g,循环50次后比容量仍然保持在492mAh/g,容量保持率为92.8%,表现出优异的电化学性能。     

锂硫电池石墨烯/硫复合正极材料的制备及其电化学性能

以经活化处理的石墨烯(AG)为主体材料, 通过化学还原法制备了石墨烯负载硫的复合正极材料AG/S。SEM、EDX和TEM测试结果表明经活化处理后形成手风琴结构的AG, 有利于电解液的浸润; 活性物质硫均匀地负载在AG表面, 同时沉积在AG的层间。电化学测试表明: 在400 mA/g电流密度下, AG/S复合正极材料首次放电比容量为1452.9 mAh/g, 经过200次循环之后, 放电比容量仍保持在909.7 mAh/g; 在1000 mA/g电流密度下, AG/S复合材料首次放电比容量为1309.9 mAh/g, 经过200次循环之后, 放电比容量仍保持在717.1 mAh/g。AG/S复合正极材料的倍率性能、库仑效率和循环性能优异, 这得益于小尺寸的硫在材料中均匀分布, 活化石墨烯优良的导电性以及其结构对硫的固化作用。     

三维石墨烯纳米球的制备及其在锂离子电池中的应用

采用直流电弧放电法制备出一种三维石墨烯纳米球材料。采用扫描电镜(SEM)、透射电镜(TEM)、拉曼光谱和X射线衍射光谱(XRD)等测试方法对三维石墨烯纳米球的形貌和结构进行了表征和研究。通过交流阻抗(EIS)、恒流充放电和循环稳定性测试等电化学测试手段来研究三维石墨烯纳米球作为锂离子电池负极材料的电化学性能。结果表明, 在电流密度为0.05 A/g下, 三维石墨烯纳米球作为锂离子电池负极材料的首次放电容量为485.9 mAh/g, 高于炭黑作负极的放电容量(401 mAh/g); 当电流密度为1 A/g时, 三维石墨烯纳米球负极材料仍然具有185.4 mAh/g的放电容量。在电流密度分别为0.5 A/g和2.5 A/g下, 充放电循环100次以后, 三维石墨烯纳米球的比容量几乎没有衰减, 这表明三维石墨烯纳米球作为锂离子电池的负极材料比炭黑具有更大的容量, 同时具有优异的循环稳定性。     

VO_2/rGO复合材料的制备及作为高容量锂离子电池负极的研究

采用简易的一步水热法实现了VO_2和rGO的有效复合,通过XRD、SEM、Raman等手段对复合材料的结构和形貌进行了表征,评估了该材料作为锂离子电池负极的电化学性能。结果显示,VO_2为片状形貌,氧化石墨烯在水热反应中被还原,与VO_2片形成了良好的复合结构。电化学数据显示,在100 mA/g电流密度下,VO_2/rGO复合材料可逆容量高达621.8mAh/g,远高于石墨的理论容量(372mAh/g)。在300mA/g电流密度下,该材料在100次循环后容量保持在384mAh/g。更重要的是,在2 000mA/g电流密度下,300次循环后容量仍维持在256mAh/g,容量保持率接近100%。基于rGO良好的导电性能以及VO_2与rGO的协同作用,制备的VO_2/rGO复合材料体现了较高的可逆比容量和良好的倍率性能及循环稳定性能,是一种具有前景的锂离子电池负极材料。     

三维结构石墨烯与硫的复合正极材料研究

在蔗糖辅助下以一步水热法制备了具有三维网络结构的石墨烯材料,以其作为与硫复合的载体实现了硫在石墨烯中的均匀分布,将此复合材料(3DGNS/S)应用于锂硫电池中表现出了优异的电化学性能:该材料在285mA/g下,首次放电比容量为1396mAh/g。2142mA/g下,首次放电比容量为713mAh/g,循环100周后,仍具有681mAh/g的放电比容量,平均每周的容量衰减率为0.04%,表现出优秀的循环性能。     

ZnO/石墨烯纳米复合材料一步水热法制备及电化学性能研究

通过一步水热法成功制得氧化锌(ZnO)/石墨烯(GN)纳米复合材料。测试表明,ZnO/GN复合材料中纤锌矿结构的ZnO纳米棒直径100~200nm,均匀担载在GN网状结构中。ZnO/GN复合材料展现出了优异的电化学性能:在0.1A/g电流密度下的可逆放电比容量达1171mAh/g;0.4A/g充放电循环测试100次后,放电容量仍然维持在305mAh/g。     

MoS2@GO三维絮状结构的制备及电化学储锂性能

以改良Hummers法制备了氧化石墨烯(GO),通过水热以及热处理制备了MoS_2@GO复合材料,探讨了MoS_2与GO物质的量比对复合材料结构、电化学性能的影响。结果表明,当MoS2与GO的物质的量比为1∶1时,所得复合材料呈现三维絮状结构并具有良好的电化学性能。其作为锂离子电池负极材料,在0.1A/g电流密度下,50次循环后放电比容量仍有879mAh/g,容量基本没有衰减。在2A/g的高电流密度下还能保持530mAh/g,当电流密度从2A/g恢复到0.1A/g,循环容量能恢复到0.1A/g时的水平,表现出优异的倍率性能。     

氧化铁和石墨烯复合负极材料的制备及性能研究

通过简易的常温搅拌复合,冷冻干燥和热处理过程合成了负极氧化铁和石墨烯复合材料,采用X射线衍射(XRD)、热重(TG)、扫描电镜(SEM)、荧光分析(EDX)、循环伏安(CV)、充放电及倍率测试探讨了材料颗粒形貌,结构和电化学性能。XRD和SEM测试表明成功合成了Fe_2O_3颗粒尺寸较小且均匀分布的复合材料。电化学性能测试结果显示,复合材料的电化学性能比纯的氧化铁及还原氧化石墨烯材料的性能有明显提升,循环50周可逆比容量保持在680mAh/g。     

石墨烯负载Fe_2O_3纳米复合材料及储能性能研究

针对锂离子电池体系,以提高负极材料可逆充放电容量为目的,制备了Fe2O3-石墨烯纳米复合材料,并利用XRD、SEM对其结构和形貌进行了表征分析,通过恒流充放电测试对其电化学性能进行系统研究。采用水热法成功制备了二元的Fe2O3-石墨烯纳米复合材料,纳米Fe2O3分布较为均匀,形貌多为菱形块状或类球状多面体,且与石墨烯片相互交叠,有效抑制了双方的团聚,形成了有利于储锂的堆砌结构。电化学性能测试表明,Fe2O3-石墨烯纳米复合材料的储锂性能大大优于石墨烯和纳米Fe2O3,30次循环后,可逆容量仍高达1 252mAh/g,循环性能优异;随着石墨烯加入量的增大,Fe2O3-石墨烯纳米复合材料的可逆容量越高。     

In situ synthesis of SnO2/graphene nanocomposite and their application as anode material for lithium ion battery

SnO₂/graphene nanocomposite was prepared via an in situ chemical synthesis method. The nanocomposite was characterized by X-ray diffraction, filed emission scanning electron microscope and transmission electron microscope, which revealed that tiny SnO₂ nanoparticles could be homogeneously distributed on the graphene matrix. The electrochemical performance of the SnO₂/graphene nanocomposite as anode material was measured by galvanostatic charge/discharge cycling. The SnO₂/graphene nanocomposite showed a reversible capacity of 665 mAh/g after 50 cycles and an excellent cycling performance for lithium ion battery, which was ascribed to the three-dimensional architecture of SnO₂/graphene nanocomposite. These results suggest that SnO₂/graphene nanocomposite would be a promising anode material for lithium ion battery.     

SnO2-reduced graphene oxide nanoribbons as anodes for lithium ion batteries with enhanced cycling stability

A nanocomposite material of SnO2-reduced graphene oxide nanoribbons has been developed. In this composite, the reduced graphene oxide nanoribbons are uniformly coated by nanosized SnO2 that formed a thin layer of SnO2 on the surface. When used as anodes in lithium ion batteries, the composite shows outstanding electrochemical performance with the high reversible discharge capacity of 1,027 mAh/g at 0.1 A/g after 165 cycles and 640 mAh/g at 3.0 A/g after 160 cycles with current rates varying from 0.1 to 3.0 A/g and no capacity decay after 600 cycles compared to the second cycle at a current density of 1.0 A/g. The high reversible capacity, good rate performance and excellent cycling stability of the composite are due to the synergistic combination of electrically conductive reduced graphene oxide nanoribbons and SnO2, The method developed here is practical for the large-scale development of anode materials for lithium ion batteries.     

锂离子电池SiOx/C/CNTs复合负极材料的制备及其电化学性能

通过机械球磨、喷雾干燥和高温热解制备锂离子电池SiO_x/C/CNTs复合负极材料,采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线能谱仪(EDS)和恒流充放电测试仪,对其物相组成、颗粒形貌及电化学性能进行了表征,并与SiO_x/C和SiO_x/C/石墨烯复合材料的性能对比。研究结果表明,CNTs的引入不仅可以增加复合材料的可逆容量,还可以有效提高材料的循环稳定性。SiO_x/C/CNTs复合负极材料在100mA/g下首次放电比容量为1 981.5mAh/g,循环100周后,放电容量仍有474.0mAh/g,倍率性能较优,具有良好的应用前景。     

Preparation of MoS2‐Coated Three‐Dimensional Graphene Networks for High‐Performance Anode Material in Lithium‐Ion Batteries

A novel composite, MoS₂‐coated three‐dimensional graphene network (3DGN), referred to as MoS₂/3DGN, is synthesized by a facile CVD method. The 3DGN, composed of interconnected graphene sheets, not only serves as template for the deposition of MoS₂, but also provides good electrical contact between the current collector and deposited MoS₂. As a proof of concept, the MoS₂/3DGN composite, used as an anode material for lithium‐ion batteries, shows excellent electrochemical performance, which exhibits reversible capacities of 877 and 665 mAh g^?1 during the 50^th cycle at current densities of 100 and 500 mA g^?1, respectively, indicating its good cycling performance. Furthermore, the MoS₂/3DGN composite also shows excellent high‐current‐density performance, e.g., depicts a 10^th‐cycle capacity of 466 mAh g^?1 at a high current density of 4 A g^?1.     

用于锂离子电池的高性能SiOx/C/石墨烯复合负极材料

以SiO、丁苯橡胶(SBR)及石墨烯为原料,通过高温歧化、机械球磨、喷雾干燥和高温热解制备电化学性能优异的锂离子电池SiO_x/C/石墨烯复合负极材料。采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线能谱仪(EDS)和恒流充放电测试仪对复合材料的物相、颗粒形貌及电化学性能等进行表征。结果表明,热解后的SiO_x/C/石墨烯复合负极材料的首次放电容量为1 807mAh/g,100次循环后,可逆容量高达1 349mAh/g,库伦效率为99.1%,循环稳定性远高于SiO_x/C和SiO_x/C/graphene前驱体,具有良好的倍率性能。     

Interface Chemistry Engineering of Protein‐Directed SnO2 Nanocrystal‐Based Anode for Lithium‐Ion Batteries with Improved Performance

A novel uniform amorphous carbon‐coated SnO₂ nanocrystal (NCs) for use in lithium‐ion batteries is formed by utilizing bovine serum albumin (BSA) as both the ligand and carbon source. The SnO₂–carbon composite is then coated by a controlled thickness of polydopamine (PD) layer through in situ polymerization of dopamine. The PD‐coated SnO₂–carbon composite is finally mixed with polyacrylic acid (PAA) which is used as binder to accomplish a whole anode system. A crosslink reaction is built between PAA and PD through formation of amide bonds to produce a robust network in the anode system. As a result, the designed electrode exhibits improved reversible capacity of 648 mAh/g at a current density of 100 mA/g after 100 cycles, and an enhanced rate performance of 875, 745, 639, and 523 mAh/g at current densities of 50, 100, 250, and 500 mA/g, respectively. FTIR spectra confirm the formation of crosslink reaction and the stability of the robust network during long‐term cycling. The great improvement of capacity and rate performance achieved in this anode system is attributed to two stable interfaces built between the active material (SnO₂–carbon composite) and the buffer layer (PD) and between the buffer layer and the binder (PAA), which effectively diminish the volume change of SnO₂ during charge/discharge process and provide a stable matrix for active materials.     

Polycrystalline SnO2 nanowires coated with amorphous carbon nanotube as anode material for lithium ion batteries

One-dimensional (1D) SnO₂ nanowires, coated by in situ formed amorphous carbon nanotubes (a-CNTs) with a mean diameter of ca. 60 nm, were synthesized by annealing the anodic alumina oxide (AAO) filled with a sol of SnO₂. X-ray diffraction (XRD) and selected area electron diffraction (SAED) patterns revealed that the prepared SnO₂ nanowires exist in polycrystalline rutile structure. The coating of carbon nanotubes has some defects on the wall after the internal SnO₂ nanoparticles were removed. The 1D SnO₂ nanowires present a reversible capacity of 441 mAh/g and an excellent cycling performance as an anode material for lithium ion batteries. This suggests that 1D nanostructured materials have great promise for practical application.     

三维花状MoS2锌离子电池正极材料的设计构筑及其储能机制研究

采用水热法设计构筑三维花状二硫化钼,并利用XRD、SEM、RAMAN、TG等测试方法对产物的结构和形貌进行了表征,进而作为正极材料组装成锌离子电池并对其进行电化学测试分析,在充放电电压区间为0.2~1.2V、电流密度为1.0A/g条件下,首次放电比容量可达63.9 mAh/g,100次循环后其放电比容量保持在53.6mAh/g,容量保持率为83.9%。较高的比容量和循环稳定性使MoS_2成为有前景的锌离子电池正极材料之一。     

In situ synthesis of SnO2 nanosheet/graphene composite as anode materials for lithium-ion batteries

A novel SnO₂/graphene composite has been synthesized via an in situ chemical synthesis method, in which single crystal SnO₂ nanosheets are uniformly grown on graphene support. The as-prepared products were characterized by X-ray diffraction, field emission scanning electron microscope, transmission electron microscope, Thermogravimetric analyses and Nitrogen adsorption/desorption. When used as an anode material for lithium ion batteries, the SnO₂/graphene composite exhibits an enhanced reversible lithium storage capacity and good cyclic performance. The first discharge and charge capacities are 1,366 and 975 mAh g^?1, respectively. After 100 cycles, the reversible discharge capacity is still maintained at 451 mAh g^?1 at the current densities of 100 mA g^?1, indicating that it’s a promising anode material for high performance lithium ion batteries.