丝网状镍钴硫金属化合物电化学性能研究

通过简单两步水热的方法在泡沫镍基底上成功制备出丝网状三维网络结构的Ni Co2S4,研究了材料的电化学性能,结果表明,Ni Co2S4@泡沫镍电极材料具有高的面积比电容,在电流密度为10 m A/cm~2时,面积比电容可达到2.87 F/cm~2;电流密度从10 m A/cm~2增大到50 m A/cm~2,电容保持率为60.9%;在负载量为6.21 mg/cm~2时,在30 m A/cm~2的高电流密度下充放电1 000次,电容保持率仍为67.3%。     

泡沫镍负载球状NiCo_2O_4电极的制备及超级电容性能研究

采用水热法在泡沫镍上生长了球状钴酸镍(NiCo_2O_4)电极材料,利用扫描电镜(SEM)观测了纳米球的表面形貌,利用X射线衍射(XRD)分析了纳米球的结构,通过循环伏安、恒流充放电测试了电极的超级电容性能。结果表明:球状NiCo_2O_4直径500~600nm,均匀生长在泡沫镍骨架上,球状之间存在空隙,可以增大与电解液的接触面积。在电流密度为1A/g,NiCo_2O_4/泡沫镍复合电极放电比电容为970F/g,循环1000次后比电容仍保持在844F/g,放电比容量保持率为82.5%,具有优异的超级电容性能。     

聚吡咯包覆NiCo_2S_4纳米管阵列的制备及其赝电容性能北大核心CSCD

使用两步水热法在泡沫镍表面生长NiCo_2S_4纳米管阵列,再通过电化学聚合技术将聚吡咯包覆在NiCo_2S_4纳米管表面形成核壳式复合材料。通过多种手段表征复合材料的物相与微结构,表明管外径约130nm,管壁厚约15nm,聚吡咯包覆膜平均厚度约8nm。研究聚吡咯包覆对NiCo_2S_4纳米管赝电容性能的影响,揭示聚吡咯改善了NiCo_2S_4纳米管的比电容、充放电性能、倍率性能和循环性能。放电比容量与未包覆的相比从1123F·g^(-1)增长到1524F·g^(-1),增加了36%;3000次循环后,聚吡咯包覆NiCo_2S_4仍释放比容量1096F·g^(-1),相比于第一次的保持率为78.5%,而未包覆的比容量只有22%的保持率。赝电容性能的改善主要是由于聚吡咯提高了NiCo_2S_4纳米管的电导率和结构稳定性。     

NiCo_2O_4微球的制备及其电化学性能

通过简单的水热法以及后续热处理,成功合成介孔NiCo_2O_4微球。利用FESEM、TEM、XPS和电化学工作站对样品的表面形貌、元素价态和电化学性能进行表征。结果表明:合成的NiCo_2O_4拥有丰富的多孔纳米针状结构,表现出较高的比表面积。由于这种三维多孔纳米结构,当NiCo_2O_4微球作为电极材料时,展现出优异的电容特性,在1A·g-1的电流密度下比电容高达1 554F·g-1,而且当电流密度增加到20A·g-1时,电容保持率为87.5%。另外,在5A·g-1的电流密度下,经过2 000次的充放电循环后,比电容仍能保持初始电容的90.4%。良好的电化学性能表明,NiCo_2O_4微球是一种理想的超级电容器电极材料。     

泡沫镍负载Co_3O_4纳米线制备及其超电容性能研究

以硝酸钴、尿素为原料,泡沫镍为基底,通过水热、煅烧法制备了Co_3O_4纳米线阵列,并采用扫描电子显微镜、透射电子显微镜及X射线衍射对Co_3O_4纳米线的微观形貌及晶体结构进行了分析。采用电化学工作站测试了Co_3O_4纳米线阵列作为超级电容器电极的电化学性能。结果显示:Co_3O_4纳米线阵列作为超级电容器电极材料在5mA/cm~2的电流密度下,具有高达1670F/g的比电容。同时显示出良好的倍率特性和较高的循环稳定性,应用前景良好。     

MnO2/NiCo2O4复合材料的控制合成及其电化学性能研究

采用两步合成法制备了MnO_2/NiCo_2O_4核壳结构纳米棒,使用场发射扫描电子显微镜、X射线衍射和电化学工作站研究了其形貌特征和电化学性能。研究结果表明,在α-MnO_2纳米棒上生长了均匀的NiCo_2O_4纳米片,这种核壳结构纳米棒所制备的电极在充放电电流密度为0.5A/g时比电容达到了434F/g,明显比纯α-MnO_2的比电容(256F/g)高,循环测试2 000次后,比电容保留量为91.8%,表现出了优秀的电化学性能,具有广阔的应用前景。     

Mn/NiO@Ni_3S_2复合材料的制备及性能研究

人们在享受经济快速发展带来的好处的同时,煤、石油等也化石燃料的燃烧也带来了一系列环境问题。那么在这样的时代背景下,发展可再生资源显得尤为重要。超级电容器,一种新型储能元件,由于其优良的性能被广泛研究。电极材料,超级电容器的重要组成部分,它会直接影响超级电容器的性能。本文利用两步水热法在泡沫镍表面成功制备出了电极材料Ni O@Ni_3S_2与Mn/Ni O@Ni_3S_2。通过电化学分析,我们发现添加了少量Mn后电极材料的电容提高了。详细地,在电流密度为5 m A cm~(-2)时,Mn/Ni O@Ni_3S_2电极的电容为3.94 F cm~(-2),而Ni O@Ni_3S_2的为2.59 F cm~(-2),且前者的电容值约为后者的1.5倍。在循环了1000圈后,我们发现Mn/Ni O@Ni_3S_2的电容保持率为82.1%,这说明掺Mn后的电极材料有良好的循环稳定性。根据以上的分析,我们可以确定Mn/Ni O@Ni_3S_2比Ni O@Ni_3S_2更适合于做超级电容器的电极材料。从某种程度上来说,这个实验也可以为以后遇到类似的改善电极材料的电容提供参考。     

原位氧化法制备Zn-Ni氢氧化物纳米片及其电荷存储特性研究

通过简单、低成本的化学浴沉积法在泡沫镍上原位生成了Zn-Ni 氢氧化物(Zn-Ni double hydroxides)纳米片。SEM观察结果表明, Zn-Ni 氢氧化物纳米片均匀附着在泡沫镍表面, 形成均一的多孔纳米片阵列层。此外, 还有大量的Zn-Ni 氢氧化物纳米片聚集成多孔团聚体, 分布于泡沫镍骨架的空隙处, 从而获得较高的活性物质负载量(4.27 mg/cm²)。CV、CP和电化学阻抗测试表明, Zn-Ni 氢氧化物纳米片在2 mol/L KOH电解液中充放电电流密度1 A/g时, 比电容为746.2 F/g(面积电容为3.18 F/cm²); 3000次充放电循环后, 仍保持70.9%的初始比电容。     

自支撑TiO_(2)@NiCo_(2)S_(4)阵列生长在柔性Ti箔上用于高性能非对称超级电容器(英文)

近年来,随着可穿戴电子产品的出现,具有可穿戴功能的高电化学性能的储能设备也备受关注。超级电容器具有循环寿命长、充放电速度快、功率密度高等优点,被认为是一种很有前途的储能设备。双金属化合物作为超级电容器的电极材料具有理论比电容较高,成本较低,环境相对友好,耐碱腐蚀等优势而受到了研究人员的关注和研究。例如典型的双金属硫化物硫钴镍便具有以上优点,但仍面临着以下几个问题：(1) 硫钴镍导电性差;(2) 硫钴镍在充放电过程中存在严重的体积膨胀。目前,很多研究方案中将导电活性物质直接生长在集流体上形成自支撑结构,这种结构形式既简化超级电容器电极制作流程又提高电化学性能。本工作以Ti片为基底,采用分步水热法先在Ti片表面生长TiO_(2)纳米带阵列,然后在其基础上包覆生长NiCo_(2)S_(4)纳米片,得到NiCo_(2)S_(4)纳米片包覆TiO_(2)纳米带的核/壳阵列结构。三电极测试结果表明,1 A·g~(-1)时TiO_(2)@NiCo_(2)S_(4)电极的比电容达到1 300 F·g~(-1)。此外,对组装的TiO_(2)@NiCo_(2)S_(4)//煤基多孔碳(CPC)不对称超级电容器(ASC)的电化学性能进行测试,结果表明：TiO_(2)@NiCo_(2)S_(4)//CPC具有较高的能量密度和功率密度(在400 W·kg~(-1)时为41.6 Wh·kg~(-1))。这种交织的三维(3D)帧结构和柔性衬底的设计开辟了在能量存储领域获得高性能柔性衬底电极材料的新机会。     

高性能CoAl-LDH六边形纳米片超级电容器电极材料的制备

采用简单的共沉淀法,制备了分散性良好且尺寸均一的钴铝层状双金属氢氧化物(CoAl-LDH)六边形纳米片电极材料,其尺寸约为2μm。三电极体系电化学测试结果表明,在电流密度为1A/g时,CoAl-LDH纳米片电极材料的质量比电容为723F/g,电流密度增加至20A/g时,电容保持率高达72%。CoAl-LDH纳米片电极材料有望成为组装高性能超级电容器的可选电极材料。     

NiCo2S4/CNTs复合材料的制备及电化学性能

采用一步水热法合成NiCo2S4和NiCo2S4/CNTs复合材料,通过进行XPS、XRD以及SEM对NiCo2S4、NiCo2S4/CNTs复合材料进行物理表征,采用三电极测试体系在电化学工作站上进行电化学测试。测试结果表明：通过掺杂CNTs改变了NiCo2S4的形貌结构,NiCo2S4在1 A/g电流密度下,比电容可以达到830 F/g,在10 A/g的大电流密度下,比电容保持率仅为78.3%;而NiCo2S4/CNTs复合材料在10 A/g下的比电容保持率可达到78.6%,并且在3 A/g电流密度下循环1000次,比电容保持率高达98.2%。     

对苯二酚增强纤维素/石墨烯电极的制备

目的 以纳米纤维素气凝胶为骨架,对苯二酚为增强相,并加入还原氧化石墨烯,制备纳米纤维素/还原氧化石墨烯复合电极薄膜,将其应用于超级电容器。方法 采用超声处理制备纳米纤维素/氧化石墨烯混合溶液;在高温高压的环境下,加入对苯二酚,采用水热合成法和冷冻干燥法制备纳米纤维素/还原氧化石墨烯气凝胶,并最终制成电极膜。结果 在纳米纤维素/还原氧化石墨烯复合气凝胶中,石墨烯可将纳米纤维素均匀包裹,形成三维多孔网络结构;纳米纤维素/还原氧化石墨烯复合电极具有良好的电化学性能,在1 mol/L的H2SO4溶液中,当电流扫描速率为1 mA/cm2时,超级电容器比面积电容高达1.621 F/cm2,且在2000次循环测试后,电容保留率为88.3％。结论 以纳米纤维素为基体制备的纳米纤维素/还原氧化石墨复合电极具有良好的电化学性能,可以用作超级电容器电极。     

碳包覆介孔四氧化三铁纳米阵列:高性能Ni/Fe水相电池阴极材料

阴极材料的开发对于可充电水相电池的发展具有重要意义.本文通过自牺牲模板法和碳包覆法相结合制备了碳包覆介孔Fe₃O₄纳米阵列阴极材料(Fe₃O₄@C MNAs).得益于包覆碳层、介孔结构和纳米阵列结构的优异特性, Fe₃O₄@C MNAs电极表现出良好的倍率性能和优秀的循环稳定性.在组装的Ni/Fe电池器件中, Fe₃O₄@C MNAs表现出较高的能量密度及功率密度(在能量密度为213.3 W h kg^-1时功率密度为0.658 kW kg^-1和在功率密度为20.7 kW kg^-1时能量密度为113.9 W h kg^-1)和出色的循环稳定性(约5000次循环后保持81.7%).     

MgCo_(2)O_(4)海胆状电极材料的制备及其电化学性能EI北大核心CSCD

采用水热法制得一种尖晶石型MgCo_(2)O_(4)海胆状电极材料,并通过X射线衍射(XRD)、X射线光电子能谱分析(XPS)、扫描电镜(SEM)、透射电镜(TEM)以及电化学工作站对产物进行了表征和电化学性能测试。通过改变所制备材料的水热反应时间,制备出团簇结构、分布较均匀以及密集度较高的MgCo_(2)O_(4)海胆状形貌。结果表明,当水热反应时间为6 h时所获得的MgCo_(2)O_(4)电极材料结构较为完善、尺寸较为均匀、电化学性能较为优异,而且在电流密度为1 mA/cm^(2)情况下,面积比电容高达6.75 F/cm^(2)。另外,对该MgCo_(2)O_(4)海胆状材料在20 mA/cm^(2)的电流密度下循环1000周次后,面积比电容保持为原来的88.4%,表现出良好的循环性能。     

Facile one-pot synthesis of NiCo<Subscript>2</Subscript>O<Subscript>4</Subscript> hollow spheres with controllable number of shells for high-performance supercapacitors

In this work,single-and double-shelled NiCo2O4 hollow spheres have been synthesized in situ by a one-pot solvothermal method assisted by xylose,followed by heat treatment.Employed as supercapacitor electrode materials,the double-shelled NiCo2O4 hollow spheres exhibit a remarkable specific capacitance (1,204.4 F·g-1 at a current density of 2.0 A·g-1) and excellent cycling stability (103.6％ retention after 10,000 cycles at a current density of 10 A·g-1).Such outstanding electrochemical performance can be attributed to their unique internal morphology,which provides a higher surface area with a larger number of active sites available to interact with the electrolyte.The versatility of this method was demonstrated by applying it to other binary metal oxide materials,such as ZnCo2O4,ZnMn2O4,and CoMn2O4.The present study thus illustrates a simple and general strategy for the preparation of binary transition metal oxide hollow spheres with a controllable number of shells.This approach shows great promise for the development of next-generation high-performance electrochemical materials.     

聚酰亚胺基活性炭的制备及其电化学性能的研究

通过炭化和进一步KOH化学活化的方法制备了聚酰亚胺基炭材料, 并将其用作双电层电容器电极材料. 采用DFT、XPS方法对其孔结构和表面化学性质进行了研究, 并通过恒流充放电等方法探讨了其电化学特性. 结果表明: 样品CPI的质量比电容是双电层电容和表面氮原子(尤其是N-5)所提供的赝电容共同作用的结果. 经活化后, 样品API比表面积达到1941m²/g, 主要形成0.7～2.0nm之间的微孔, 氮原子的影响可以忽略, 在50mA/g的放电电流密度下质量比电容达300F/g, 且电流密度达到1000mA/g时, 电容保持率仍为86.1%; 交流阻抗测试也表明样品API具有良好的双电层电容特性, 是一种新型的双电层电容器电极材料.     

Metal-organic framework derived hierarchical NiCo2O4 triangle nanosheet arrays@SiC nanowires network/carbon cloth for flexible hybrid supercapacitors

To overcome the disadvantages of traditional powder electrodes,such as the insufficient performance,the aggregation of active materials,and the complex fabrication process,rationally constructing free-standing electrode materials with hierarchical architecture is an effective and promising method,which could further improve the electrochemical properties.Herein,using metal-organic framework nanoar-rays (MOFNAs) as self-sacrificial templates and SiC nanowires (SiCNWs) network as nanoscale conductive skeletons,we successfully fabricated the hierarchical core-shell SiCNws@NiCo2O4NAs on carbon cloth (CC)substrate.Taking advantages of structural merits,such as hierarchical porous triangle-like NiCo2O4NAs,the interwoven SiCNWs network and conductive CC substrate,when evaluated as a binder-free superca-pacitor electrode,the CC/SiCNWs@NiCo2O4NAs shows a high specific capacitance of 1604.7 F g-1 (specific capacity of 222.9 mA h g-1) at 0.5 A g 1,good rate performance,and excellent cycling stability.Signifi-cantly,the hybrid supercapacitor assembled with CC/SiCNWs@NiCo2O4NAs as the cathode and MOF derived CC/SiCNWs@CNAs as the anode,could deliver a high specific density of 49.9 W h kg-1 at a specific power of 800 W kg-1,stable cycling performance,and good flexibility.Impressively,this feasible strategy for fabricating hierarchical structure displays great potential in the field of energy storage.     

Promoting the Na+-storage of NiCo2S4 hollow nanospheres by surfacing Ni-B nanoflakes

Sodium ion battery(SIB)is considered as the potential alternative for next generation energy system to succeed the lithium ion battery(LIB)due to the low price and vast abundance of Na resource.Ternary metal sulfide is identified as an important redox conversion type of negative electrode for SIB.In this study,amorphous nickel boride(Ni-B)nanoflakes are introduced into the hollow Ni-Co sulfide nanospheres by a facile in situ solution growth route to promote the electrochemical performance of Na+-storage.Elec-trochemical measurements demonstrate that the Ni-B component could effectively improve the redox kinetics of the conversion reaction and structural stability during long-term Na+insertion/extraction.For example,the NiCo2S4@Ni-B composites display a high reversible capacity of 251.9 mA h g-1 at the current density of 1.0 A g-1 after 200 cycles,much higher than that of bare NiCo2S4(37.4 mA h g-1 at 1.0 A g-1 after 200 cycles).As a consequence,these results demonstrate a new sight to explore heterostructures of mixed metal-sulfides electrode materials with superior Na+-storage performances.     

High performance flexible energy storage device based on copper foam supported NiMoO4 nanosheets-CNTs-CuO nanowires composites with core-shell holey nanostructure

Because of the intensified electrochemical activities,mixed metal oxides as a representative for pseudo-capacitive materials play a key role for high performance supercapacitor electrodes.Nevertheless,low ion and electron transfer rate and poor cycling performance in the electrode practically restrict further promotion of their electrochemical performance.In order to offset the defect,a novel copper(Cu)foam-supported nickel molybdate nanosheet decorated carbon nanotube wrapped copper oxide nanowire array(NiMoO4 NSs-CNTs-CuO NWAs/Cu foam)flexible electrode is constructed.The as-prepared elec-trode demonstrates a unique core-shell holey nanostructure with a large active surface area,which can provide a large number of active sites for redox reactions.Besides,the CNTs networks supply improved conductivity,which can hasten electron transport Through this simple and efficient design method,the spatial distribution of each component in the flexible electrode is more orderly,short and fast electron transport path with low intrinsic resistance.As a result,the NiMoO4 NSs-CNTs-CuO NWAs/Cu foam as an adhesiveless supercapacitor electrode material exhibits excellent energy storage performance with high specific areal capacitance of 23.40 F cm-2 at a current density of 2 mA cm-2,which outperforms most of the flexible electrodes reported recently.The assembled asymmetric supercapacitor demonstrates an energy density up to 96.40 mW h cm-3 and a power density up to 0.4 W cm-3 under a working voltage window of 1.7 V.In addition,outstanding flexibility of up to 100° bend and good cycling stability with the capacitance retention of 82.53％after 10,000 cycles can be obtained.