有序中孔炭的制备及电性能研究

采用微湿含浸法制备了一系列具有不同比表面积和孔径分布的超级电容器有序中孔炭材料,同时采用Al-SBA-15为模板剂制得具有六方排列的空心炭管CMK-5.所制得的有序中孔炭的BET比表面积随糠醇加入量的增加而减小.电化学性能测试结果表明,在1mA·cm-2的充放电电流密度下各中孔炭材料比电容的大小顺序与其BET比表面积的大小顺序相一致.在所有样品中AlSC-0.8由于具有最大的比表面积,因此其比电容最大,达87.8F·g-1.倍率性能测试结果表明,具有CMK-3结构的SC-2.0的倍率性能最好,在50mA·cm-2的放电电流密度下其放电比电容接近AlSC-0.8有序中孔炭的水平.     

Facile Synthesis of NiCo2O4 Nanowire Arrays/Few-Layered Ti3C2-MXene Composite as Binder-Free Electrode for High-Performance Supercapacitors

Herein, a 3D hierarchical structure is constructed by growing NiCo₂O₄ nanowires on few-layer Ti₃C₂ nanosheets using Ni foam (NF) as substrate via simple vacuum filtration and solvothermal treatment. Ti₃C₂ nanosheets are directly anchored on NF surface without binders or surfactants, and NiCo₂O₄ nanowires composed of about 15 nm nanoparticles uniformly grow on Ti₃C₂/NF skeleton, which can provide abundant active sites and ion diffusion pathways for enhancing electrochemical performance. Benefiting from the unique structure feature and the synergistic effects of active materials, NiCo₂O₄/Ti₃C₂ exhibits a high specific capacitance of 2468 F g⁻¹ at a current density of 0.5 A g⁻¹ and a good rate performance. Based on this, an asymmetric supercapacitor (ASC) based on NiCo₂O₄/Ti₃C₂ as positive electrode and activated carbon (AC)/NF as negative electrode is assembled. The ASC achieves a high specific capacitance of 253 F g⁻¹ at 1 A g⁻¹ along with 91.5% retention over 10,000 cycles at 15 A g⁻¹. Furthermore, the ACS presents an outstanding energy density of 90 Wh kg⁻¹ at the power density of 2880 W kg⁻¹. This work provides promising guidance for the fabrication of binder-free, free-standing and hierarchical composites for energy storage application.     

Effect of Manganese Valence on Specific Capacitance in Supercapacitors of Manganese Oxide Microspheres

Manganese oxides have attracted great interest in electrochemical energy storage due to high theoretical specific capacitance and abundant valence states. The multiple valence states in the redox reactions are beneficial for enhancing the electrochemical properties. Herein, three manganese microspheres were prepared by a one-pot hydrothermal method and subsequent calcination at different temperatures using carbon spheres as templates. The trivalent manganese of Mn₂O₃ exhibited multiple redox transitions of Mn³⁺/Mn²⁺ and Mn⁴⁺/Mn³⁺ during the intercalation/deintercalation of electrolyte ions. The possible redox reactions of Mn₂O₃ were proposed based on the cyclic voltammetry and differential pulse voltammogram results. Mn₂O₃ microsphere integrated the advantages of multiple redox couples and unique structure, demonstrating a high specific capacitance and long cycling stability. The symmetric Mn₂O₃//Mn₂O₃ device yielded a maximum energy density of 29.3 Wh kg⁻¹ at 250 W kg⁻¹.     

Potentiostatic and cyclic voltammetric deposition of nanostructured manganese oxide for supercapacitor applications

Nanostructured manganese oxide was produced by potentiostatic and cyclic voltammetric deposition techniques from aqueous KMnO₄ solutions. Scanning electron microscopy (SEM) and X-ray diffraction were used to study the morphology and crystal structure of the deposited films. The electrochemical properties of deposited films, that obtained by two techniques, were investigated via performing the cyclic voltammetric tests. The results showed the higher specific capacitances of the nanostructured manganese oxide electrodes which have been produced via cyclic voltammetric deposition. The good retention was obtained for all synthesized electrode materials.     

基于离子液体的超级电容在3 V及65 oC老化条件下的铝碳界面效应

相比于传统乙腈电解液体系的超级电容器,离子液体基超级电容器具有工作窗口电压高,能量密度大,不可燃等优点,适用于碳中和时代清洁但不稳定电力领域的大规模储能。然而,目前的工作主要集中在对纽扣型离子液体-超级电容器的研究上,有关软包式离子液体-超级电容器的长循环寿命评测的报道较少。构建可靠的超级电容器用于长时间测试或在高温下开展加速老化测试,应考虑集流体/电极界面的良好接触,以最小化电荷转移电阻。本文以包覆不同碳层的泡沫铝为集流体,研究了超级电容器新系统中的碳-铝界面效应。通过环氧树脂薄膜碳化得到的均匀无定形碳层,相比通过PVDF粘附石墨烯碳层,赋予了铝相和碳相更强的相互作用。此外,为了充分挖掘大离子尺寸的离子液体电解液的潜力,本文采用介孔碳电极实现离子在介孔间的快速扩散。因此,本工作首次制备了由介孔碳电极、离子液体电解液和覆碳三维泡沫铝集流体组成的新结构软包式超级电容器。以自制的容量为37 F的不同软包式超级电容器件,通过3 V、65 ^oC、500 h加速老化试验,研究了其时间依赖性的电化学性能,包括CV测试、恒流充放电测试、电容值、接触电阻、电化学阻抗谱等。相比石墨烯包覆的泡沫铝基器件,无定形碳层包覆的泡沫铝基器件表现出更高的电容保持率。此外,我们还对ESR进行了等效电路拟合,并深入分析了接触电阻、电荷转移电阻、韦伯电阻,研究了C-Al界面对高能量密度超级电容器的高性能和稳定性的影响。500小时老化测试前后的极片表征证实了上述结果。高温、高压条件使粘附石墨烯碳层的泡沫铝界面结构不可靠。而泡沫铝表面原位包覆的碳层在老化过程中表现出较强的相互作用和稳定的结构。这些坚实的数据为面向高能量密度、高功率密度和长循环寿命,进一步优化高窗口电压超级电容器提供了充足的信息。     

Application of Octanohydroxamic Acid for Salting out Liquid–Liquid Extraction of Materials for Energy Storage in Supercapacitors

The ability to achieve high areal capacitance for oxide-based supercapacitor electrodes with high active mass loadings is critical for practical applications. This paper reports the feasibility of the fabrication of Mn₃O₄-multiwalled carbon nanotube (MWCNT) composites by the new salting-out method, which allows direct particle transfer from an aqueous synthesis medium to a 2-propanol suspension for the fabrication of advanced Mn₃O₄-MWCNT electrodes for supercapacitors. The electrodes show enhanced capacitive performance at high active mass loading due to reduced particle agglomeration and enhanced mixing of the Mn₃O₄ particles and conductive MWCNT additives. The strategy is based on the multifunctional properties of octanohydroxamic acid, which is used as a capping and dispersing agent for Mn₃O₄ synthesis and an extractor for particle transfer to the electrode processing medium. Electrochemical studies show that high areal capacitance is achieved at low electrode resistance. The electrodes with an active mass of 40.1 mg cm⁻² show a capacitance of 4.3 F cm⁻² at a scan rate of 2 mV s⁻¹. Electron microscopy studies reveal changes in electrode microstructure during charge-discharge cycling, which can explain the increase in capacitance. The salting-out method is promising for the development of advanced nanocomposites for energy storage in supercapacitors.     

三维钴基MOF[KCo7(OH)3(ip)6(H2O)4]·12H2O作为超级电容器的高容量电极材料

为了开发较高能量密度的超级电容器,我们通过简单的溶剂热反应合成了一种三维的钴基金属有机框架(MOF)化合物([KCo7(OH)3(ip)6(H2O)4]·12H2O,Co?ip;ip=间苯二甲酸根),并考察了其作为超级电容器电极材料的性能。Co?ip电极显示出高比电容、良好的循环稳定性和优良的倍率性能。在1 mol·L^-1 KOH溶液中,电流密度为1 A·g^-1时,其最大比电容为1660 F·g^-1。在电流密度为2 A·g^-1条件下,循环3000次后,其比电容的保持率为82.7%。优异的超级电容性能可归因于Co?ip具有纳米尺寸颗粒和三维的多孔结构。     

Improving the performance of all-solid-state supercapacitors by modifying ionic liquid gel electrolytes with graphene nanosheets prepared by arc-discharge

Ionic liquid gel polymers have widely been used as the electrolytes in all-solid-state supercapacitors, but they suffer from low ionic conductivity and poor electrochemical performance. Arc discharge is a fast, low-cost and scalable method to prepare multi-layered graphene nanosheets, and as-made graphene nanosheets （denoted as ad-GNSs） with few defects, high electrical conductivity and high thermal stability should be favorable conductive additive materials. Here, a novel ionic liquid gel polymer electrolyte based on an ionic liquid （EM1MNTF2） and an copolymer （P（VDF-HFP）） was modified by the addition of ad-GNSs as an ionic conducting promoter. This modified gel electrolyte shows excellent thermal stability up to 400 ℃ and a wide electrochemical window of 3 V. An all-solid-state supercapacitor based on commercial activated carbon was fabricated using this modified ionic liquid gel polymer electrolyte, which shows obviously improved electrochemical behaviors compared with those of the corresponding all-solid-state supercapacitor using pure ionic liquid gel polymer electrolyte. Specially, smaller internal resistance, higher specific capacitance, better rate performance and cycling stability are achieved. These results indicate that the ionic liquid gel polymers modified by ad-GNSs would be promising and suitable gel electrolytes for high performance all-solid-state electrochemical devices.     

对苯二胺缩对苯二甲醛席夫碱及其配合物的制备和电化学性能

以对苯二胺和对苯二甲醛为原料缩合制备出对苯二胺缩对苯二甲醛席夫碱聚合物（PT）,研究了采用不同物质的量之比的单体所制备的聚合物的电化学性能。利用席夫碱聚合物中N原子上的孤对电子与不同金属离子配位形成席夫碱配位聚合物（PT-M）,并对所形成聚合物的电化学性能进行了研究。采用X射线衍射（XRD）、红外（IR）、热重-差示扫描量热法（TG-DSC）、扫描电子显微镜（SEM）和能谱（EDS）对产物进行了表征,PT-M的XRD峰强度相比于PT明显降低,表明金属离子配位进入分子链骨架中引起的空间位阻减少了分子链排列的有序性。采用循环伏安、恒电流充放电和交流阻抗评价了所制备的配位聚合物材料的电化学性能。研究发现,聚席夫碱铝配合物（PT-Al）表现出较优的电化学性能,在0.5 A·g^-1的电流密度下其电容值为649.6 F·g^-1,并且具有较好的循环稳定性,在8 A·g^-1的电流密度下循环1 000次后仍有80.9%的电容保持率。     

CeO2 quantum dots doped Ni-Co hydroxide nanosheets for ultrahigh energy density asymmetric supercapacitors

By integrating the merits of lanthanide elements and quantum dots, we firstly design CeO₂ quantum dots doped Ni-Co hydroxide nanosheet via a controllable synthetic strategy, which exhibits a large specific capacitance (1370.7 F/g at 1.0 A/g) and a good cyclic stability (90.6% retention after 4000 cycles). Moreover, we assemble an aqueous asymmetric supercapacitor with the obtained material, which has an extremely high energy density (108.9 Wh/kg at 378 W/kg) and outstanding cycle stability (retaining 88.1% capacitance at 2.0 A/g after 4000 cycles).