储能电池用空心介孔碳/硫复合正极材料的制备及性能改进

针对高比能二次电池中,锂硫电池在反应过程中出现的中间产物溶解流失及体积膨胀等问题,采用模板法制备了一种具有空心结构的高孔容介孔碳球(标记为SiO_2~-空心碳),不仅提高了载硫量,而且可将多硫化物吸附在球体的空心结构和壳层的介孔孔隙中,从而抑制活性物质的溶解流失。扫描电子显微镜(SEM)和透射电子显微镜(TEM)、氮气吸脱附表征结果表明多孔碳呈空心球结构,壳层布满介孔孔隙,孔径约为2～4 nm; X-射线衍射(XRD)图谱说明单质硫均匀分散在空心碳孔隙结构中;热重分析结果显示,SiO_2~-空心碳/S复合材料的硫含量为74. 2%;电化学测试表明,其首周放电比容量增加至1608. 6(mA·h·g~(-1)),循环100周后仍保持在863. 4(mA·h·g~(-1))以上,说明SiO_2~-空心碳/S复合材料具有较好的电化学活性及循环稳定性。采用KS6为导电剂,可以使复合硫电极循环100周后的可逆比容量提高至961(mA·h·g~(-1)),容量保持率提高至61. 7%,可见KS6导电剂可以明显改善SiO_2~-空心碳/S复合材料的循环性能。     

MnO/C自支撑复合纳米纤维膜的制备及其电化学性能

以MnO_2/PAN/DMF为前驱体,通过静电纺丝和惰性气氛下退火处理制备出MnO/C纳米纤维,对样品进行了XRD、SEM以及电化学性能分析。结果表明:制得的复合膜纤维直径为300~500 nm;其中MnO_2添加量为1.0g时制得的纳米纤维膜的形貌和性能最理想,当电流密度为1.0 A·g~(-1)时,经过200个循环,容量仍然保持在320mA·h·g~(-1);在电流密度3.0 A·g~(-1)下,可逆容量为201 mA·h·g~(-1),展现了极好的倍率性能和循环性能。     

多孔五氧化二铌球的合成及其电化学性能研究

以表面活性剂CTAB为模板,通过水热法及煅烧过程合成了多孔Nb_2O_5微球。对所得产品的表征和电化学性能测试结果表明:合成了正交结构的Nb_2O_5球,且其单分散性能较好,直径为900 nm左右,球上分布有很多孔径为2~70 nm的小孔,形成了独特的多孔结构,该结构增加了材料的比表面积,其比表面积为340 m~2/g。独特的多孔结构和较大的比表面积使得其作为锂离子电池负极材料时表现出优异的电化学性能:首次容量较高,多孔Nb_2O_5球的首次充放电容量分别为297.8和395.9 m A·h·g~(-1);循环性能稳定,在电流密度为20 m A/g下充放电时,第3次循环后的库伦效率几乎达到100%;倍率性能优异,在50,100 m A/g电流密度下,经过20次循环后的容量分别为139.6,117.1 m A·h·g~(-1),容量保持率都为90%以上。     

钠离子电池负极材料 SbSn/石墨烯复合物的合成及电化学性能测试

通过化学共沉淀法制备SnSb纳米合金,并以此为主体材料表面包覆石墨烯的核壳结构复合材料SbSn/rGO用作钠离子电池负极材料。通过XRD、SEM、EDS测试分析材料的物相结构与形貌,通过循环伏安、恒流充放电测试分析材料的电化学性能。研究表明,SbSn/rGO复合材料缓解了SnSb纳米合金团聚和体积膨胀效应,增强了材料的循环稳定性和倍率性能。SbSn/rGO复合材料150 mA·g~(-1)电流密度及0～3 V充放电电压测试,首次充放电容量为650、700 mA·h·g~(-1),第50次循环的放电比容量保持在350 mA·h·g~(-1),大幅度提高钠电负极材料比容量和循环稳定性。     

MOF-5衍生碳作为水系锌离子复合电容器阴极储能性能研究

采用锌金属有机配合物(MOF-5)煅烧得到的多孔碳材料作为阴极材料,以锌箔作为阳极,硫酸锌中系水溶液作为电解液构建了锌离子复合电容器。在电化学性能测试中,锌离子复合电容器表现出了优异的电化学性能,如高放电比容量(在1 A·g~(-1)的电流密度下放电比容量为55 mAh·g~(-1)),良好的倍率性能,高能量密度(46 Wh·kg~(-1)),优异的循环稳定性(在1 A·g~(-1)的电流密度下进行8 000次充放电循环后,锌离子复合电容器的放电比容量保持率接近100%)。     

新型铝离子电池正极材料MoS_2的制备及其电化学性能

以钼酸钠和硫代乙酰胺为原料,水为溶剂,采用水热法制备出具有优异电化学性能的花瓣状MoS_2纳米结构。研究了制备过程中反应温度、时间对产物形貌及电化学性能的影响。利用X射线衍射(XRD)、扫描电子显微镜(SEM)对产物的微观结构和形貌进行了表征,并对其电化学性能及反应过程机理进行了研究。结果表明:在水热温度为200℃,反应时间为28h条件下,所制备产物的结晶性最好,组成花瓣状的片层结构堆垛最为有序;以该花瓣状MoS_2作为铝离子电池正极材料,在充放电电流密度为10 mA·g~(-1)时,首次放电容量达到127.8mA·h·g~(-1),循环80圈后,其放电容量依然保持在44.4mA·h·g~(-1),上述结果表明,所制备产物具有优异的电化学性能和良好的循环稳定性。     

纳米多孔SnSb合金在钠离子电池中的应用

采用化学脱合金法制备了具有纳米多孔结构的SnSb合金材料,并将其应用于钠离子电池的负极.电化学性能测试结果表明,与SnSb颗粒相比,这种具有孔道与韧带双连续结构的合金负极具有高的放电比容量、优良的循环性能和倍率性能.在50 mA·g~(-1)的电流密度下首次放电比容量为419.9 mAh·g~(-1);25次循环之后容量可达264.3 mAh·g~(-1);在150 mA·g~(-1)的放电倍率下,其放电比容量仍可达350.2 mAh·g~(-1).     

锂离子电池负极材料SnO_2掺杂石墨烯与多孔碳的改性研究

为改善SnO_2作为锂离子电池负极材料的电化学表现性能,利用溶剂热法制备SnO_2纳米颗粒,通过球磨法将SnO_2与多孔导电碳和石墨烯掺杂制得SnO_2/石墨烯/多孔碳复合材料,并研究了掺杂不同比例多孔碳的复合材料的电化学性能。结果表明:含15.79%多孔碳的SnO_2/石墨烯/多孔碳复合材料性能最好,初始可逆容量达1 221 m Ah·g~(-1);拥有良好的循环稳定性,在200 m A·g~(-1)电流密度下循环50次后,放电容量维持在834 m Ah·g~(-1);在100,200,400,800,1 600 m A·g~(-1)电流密度下,放电容量分别为1 221,1 093,993,796,526 m Ah·g~(-1),表现出良好的倍率性能。适量的多孔碳结合层状石墨烯形成特殊的物理结构,强化了SnO_2在充放电过程中的结构稳定性,进而提高了其电化学循环稳定性;石墨烯/多孔碳复合材料的掺杂提高了锂离子电池负极材料SnO_2的导电性,同时提高了其电化学性能。     

CTAB辅助二次水热法合成o-LiMnO_2微米棒及其电化学性能

通过十六烷基三甲基溴化铵(CTAB)辅助二次水热法合成了o-LiMnO_2微米棒。首先以KMnO_4和CTAB为原料合成了γ-MnOOH微米棒,然后再以γ-MnOOH为前驱物在LiOH溶液中通过第2步水热反应制备出表面粗糙的o-LiMnO_2微米棒。实验结果表明:当第2步水热反应温度为200℃、时间为15 h、n(Li)∶n(Mn)=12∶1时所得样品的电化学性能最优。该样品在电流密度为30、200 mA·h·g~(-1)时最大放电容量分别达到220、117 mA·h·g~(-1),且经过40次循环后放电容量仍高达176、112 mA·h·g~(-1),表现出较好的循环稳定性和倍率性能。     

纳米多孔铁掺杂钒氧化物电极材料的制备及其电化学性能

为了利用简单的生产工艺制备性能优异的锂离子电池负极材料,采用电弧熔炼-甩带的工艺制备出铁钒合金条带,再通过氧化还原方法成功制备出纳米多孔铁掺杂钒氧化物(Fe-VO_x)复合材料,对材料物相和结构进行了表征,并且对比分析了在不同还原温度下纳米多孔Fe-VO_x复合材料的电化学性能。结果表明:在还原温度为500℃、5%H_2/Ar混合气氛下,材料电化学性能最优,在电流密度为0.1 A/g下,初始放电比容量为563.4 mA·h/g,在循环100圈后的放电比容量仍能达到441 mA·h/g,循环容量保持率达到78.2%,远大于石墨的理论比容量372 mA·h/g。这说明纳米多孔铁掺杂钒氧化物复合材料能够有效提高锂离子电池的能量密度,并且具有良好的电化学性能。     

Graphene as a high-capacity anode material for lithium ion batteries

Graphene was produced via a soft chemistry synthetic route for lithium ion battery applications. The sample was characterized by X-ray diffraction, nitrogen adsorption-desorption, field emission scanning electron microscopy and transmission electron microscopy, respectively. The electrochemical performances of graphene as anode material were measured by cyclic voltammetry and galvanostatic charge/discharge cycling. The experimental results showed that the graphene possessed a thin wrinkled paper-like morphology and large specific surface area (342 m²·g^?1). The first reversible specific capacity of the graphene was as high as 905 mA·h·g^?1 at a current density of 100 mA·g^?1. Even at a high current density of 1000 or 2000 mA·g^?1, the graphene maintained good cycling stability, indicating that it is a promising anode material for high-performance lithium ion batteries.     

锂离子电池负极材料多孔硅/硅铁合金的制备及性能

为改善锂离子电池硅负极材料的电化学性能,利用镁热还原法制备了不同铁掺杂量的多孔硅/硅铁合金复合材料,并对其结构以及在锂离子电池中的充放电性能进行了研究.材料均呈现多孔结构,硅铁合金均匀分布在孔道内部.多孔硅/硅铁合金复合材料具有较好的循环稳定性,在0.1C倍率下循环100圈后可逆容量为1 133.5 m A·h/g,容量保持率为66%;在1C倍率下可逆容量仍可以达到776.9 m A·h/g.     

锂离子电池负极材料SnO2-Gn-C三元复合物的制备及其电化学性能

通过两步水热法合成了可用作锂离子电池负极材料的二氧化锡-石墨烯-炭（SnO2-Gn-C）三元复合物.采用X射线粉末衍射（XRD）、透射电镜（TEM）和电化学测试研究了SnO2-Gn-C复合物的晶型结构、形貌和电化学性能,并考察了反应温度和Sn/Gn物质的量比对复合物电化学性能的影响.实验结果显示,SnO2-Gn-C复合物在200mA· g-1电流密度下初始放电比容量达到1 225mA·h·g-1,50次充放电循环后比容量仍有约229mA.h·g-1.SnO2-Gn-C良好的电化学性能主要归结于大比表面积的石墨烯对SnO2纳米粒子的良好分散作用、石墨烯和炭的高导电性以及炭包覆后的复合物充放电时体积效应的显著减小.     

Co-MOF Derived NiCo-LDH Three-Dimensional Nanostructure on Carbon Cloth for High-Performance Supercapacitors

A well-designed cobalt-based metal organic framework(Co-MOF)derived NiCo layered doubleh ydroxides(NiCo-LDH)three-dimensional porous nanostructures has been fabricated on carbon cloth(CC)b y the ion etching/exchange reaction method. The morphology and structure of the synthesized samples have been characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),transmissione lectron microscopy(TEM)and X-ray photoelectron spectroscopy(XPS). As an electrode,the optimalN iCo-LDH shows a hi...     

以Mn3O4为锰源合成高性能LiMn2O4正极材料

以Mn3O4为锰源,采用固相反应法,在较低的温度(650℃)制得尖晶石LiMn2O4正极材料。采用X射线衍射(XRD)、扫描电镜(SEM)、循环伏安和恒流充放电等技术对其相组成、微结构和电化学性能进行表征。结果表明该正极材料结晶良好,一次粒径约为150 nm。它的电化学性能,尤其是循环性能,明显优越于在较高温度合成的LiMn2O4。在电流密度为74 mA?g-1时,测得比容量为128 mAh?g-1,在1 480 mA?g-1时,比容量为105 mAh?g-1;在室温、148 mA?g-1充放电200次循环后,容量保持率为93%。     

Controllable preparation and superior rate performance of spinel LiMn<Subscript>2</Subscript>O<Subscript>4</Subscript> hollow microspheres as cathode material for lithium-ion batteries

Spinel LiMn₂O₄ microspheres and hollow microspheres with adjustable wall thickness have been prepared using controllable oxidation of MnCO₃ microspheres precursors and following solid reactions with lithium salts. Scanning electron microscopy (SEM) investigations demonstrate that the microsphere morphology and hollow structure of precursors are inherited. The effect of hollow structure properties of as-prepared LiMn₂O₄ on their performance as cathode materials for lithium-ion batteries has been studied. Electrochemical performance tests show that LiMn₂O₄ hollow microspheres with small wall thickness exhibit both superior rate capability and better cycle performance than LiMn₂O₄ solid microspheres and LiMn₂O₄ hollow microspheres with thick wall. The LiMn₂O₄ hollow microspheres with thin wall have discharge capacity of 132.7 mA·h·g^-1 at C/10 (14.8 mA·g^-1) in the first cycle, 94.1% capacity retention at C/10 after 40 cycles and discharge capacity of 116.5 mAh·g^-1 at a high rate of 5C. The apparent lithium-ion diffusion coefficient (D _app) of as-prepared LiMn₂O₄ determined by capacity intermittent titration technique (CITT) varies from 10^-11 to 10^-8.5 cm²·s^-1 showing a regular “W” shape curve plotted with test voltages. The Dapp of LiMn₂O₄ hollow microspheres with thin wall has the largest value among all the prepared samples. Both the superior rate capability and cycle stability of LiMn₂O₄ hollow microspheres with thin wall can be ascribed to the facile ion diffusion in the hollow structures and the robust of hollow structures during repeated cycling.     

Electrochemical performance of LiFePO4/（C＋Fe2P） composite cathode material synthesized by sol-gel method

A LiFePO4/(C+Fe2P) composite cathode material was prepared by a sol-gel method using Fe(NO3)3·9H2O,LiAc·H2O,NH4H2PO4 and citric acid as raw materials,and the physical properties and electrochemical performance of the composite cathode material were investigated by X-ray diffractometry(XRD),scanning electron microscopy(SEM),transmission electron microscopy(TEM) and electrochemical tests.The Fe2P content,morphology and electrochemical performance of LiFePO4/(C+Fe2P) composite depend on the calcination tempera...     

Modification of natural graphite using pitch through dynamical melt-carbonization

The graphite was modified using pitch through dynamical melt-carbonization, and the effects of modification temperature and the amount of pitch on the characteristics of graphite were investigated. The structure and characteristics of the graphite were determined by X-ray diffractometry(XRD), scanning electron microscopy(SEM), particle size analysis and electrochemical measurements. The results show that the modified graphite has a disordered carbon/graphite composite structure, larger average particle diameter, greater tap density, and better electrochemical characteristics than the untreated graphite. The sample coated with 10% pitch dynamical melt-carbonized at 400 ℃ for 3 h and heat-treated at 850 ℃ for 2 h has better electrochemical performances with a reversible capacity of 360.5 mA·h/g, a irreversible capacity of 41.0 mA·h/g, and an initial coulombic efficiency of 89.8% compared with natural graphite and disordered carbon. The cycling stability of the Li/C cell with modified graphite as anodes is improved, and its capacity retention ratio at the 30th cycle is up to 94.37%.     

Soft chemical synthesis and electrochemical properties of tin oxide-based materials as anodes for lithium ion batteries

1　INTRODUCTIONWiththedevelopmentoflithiumionbatteries ,thereisanincreasingdemandforelectrodematerialspossessinghighcapacity .Muchresearchwasunder takentosearchfornewanodematerialsin placeofcarbon (theoreticalmaximumcapacityof 372mA·h·g- 1)toimproveenergydensityforrechargeablelithi umionbatteries[110 ] .Notably ,tinoxide basedmate rials ,aspossiblecandidatesforthenextgenerationanodematerialsforLi ionbatteriesduetotheirhighlithiumstoragecapacityandlow potentialoflithiumionintercalation ,…