3D Hollow Flower‐like CoWO4 Derived from ZIF‐67 Grown on Ni‐foam for High‐Performance Asymmetrical Supercapacitors

A three‐dimensional (3D) hollow CoWO₄ composite grown on Ni‐foam (3D?H CoWO₄/NF) based on a flower‐like metal‐organic framework (MOF) is designed by utilizing a facile dipping and hydrothermal approach. The 3D?H CoWO₄/NF not only possesses large specific areas and rich active sites, but also accommodates volume expansion/contraction during charge/discharge processes. In addition, the unique structure facilitates fast electron/ion transport of 3D?H CoWO₄/NF. Meanwhile, a series of characterization measurements demonstrate the appropriate morphology and excellent electrochemical performance of the material. The 3D?H CoWO₄/NF possesses a high specific capacitance of 1395 F g^?1, an excellent cycle stability with 89% retention after 3000 cycles and superior rate property. Furthermore, the 3D?H CoWO₄/NF can be used as a cathode to configurate an asymmetric supercapacitor (ASC), and 3D?H CoWO₄/NF//AC shows a good energy density (29.0 W h kg^?1). This work provides a facile method for the preparation of 3D‐hollow electrode materials with high electrochemical capability for advanced energy storage devices.     

Multifunctional micro-/nanoscaled structures based on polyaniline: an overview of modern emerging devices

With the advent of Materials Science-based technological advances, the fabrication of materials that could simultaneously exhibit both mechanical and processing properties of polymers and unique electrical characteristics of metals is a requirement with prior mandate. With the development of conducting polymers, great opportunities have been established, and novel devices with the significant features have emerged. Polyaniline (PANI) and its derivatives have attracted immense attention because of their fascinating properties, including high conductivity, inexpensiveness of starting material, unique redox behavior, facile synthesis, tunable properties, appropriate electrochemical and environmental stability, and strong bimolecular interactions. Nanostructures based on PANI have shown improved functionalities in various applications. In this article, different synthesis strategies such as interfacial polymerization, microwave-assisted polymerization, and sonochemical polymerization among others have been summarized. Besides, PANI-based nanocomposites and their various industrial, as well as biomedical applications in supercapacitors, batteries, gas vapor sensors, printable electronics, electrochromics, actuators, electrostatic dissipation, electromagnetic interference shielding, corrosion protection, filtration membranes, microbial fuel cell, biosensors, tissue engineering, and drug delivery systems, have been discussed in detail.     

功能化石墨烯/聚苯胺复合电极材料的制备和电化学性能

利用水合肼还原十八胺(ODA)接枝的氧化石墨烯(GO),得到了十八胺功能化石墨烯(ODA-G),将ODAG与聚苯胺(PANI)通过溶液共混法,制备了功能化石墨烯和聚苯胺纳米复合材料(ODA-G/PANI).采用傅里叶变换红外(FTIR)光谱、X射线衍射(XRD)、热重分析(TGA)、拉曼(Raman)光谱及透射电镜(TEM),对复合材料的结构和形貌进行了表征;利用循环伏安、恒流充放电及交流阻抗谱等,对复合材料的电化学性能进行了测试.结果显示,少量ODA-G的引入为PANI的电化学氧化还原反应提供了更多的电子通道和活性位置,有利于提高PANI的赝电容.在电流密度1.0 A·g-1下,2%(w)ODA-G/PANI的比电容达到787 F·g-1,而相应的PANI仅有426 F·g-1.此外,ODA-G/PANI的循环稳定性也远高于纯PANI.     

互通多孔碳/二氧化锰纳米复合材料的原位水热合成及电化学性能

以互通多孔碳（IPC）为载体,水热条件下在碳表面原位反应生成纳米结构的二氧化锰（MnO₂）,制备互通多孔碳/二氧化锰纳米（IPC/MnO₂）复合电极材料. 采用扫描电镜（SEM）,透射电镜（TEM）,X射线衍射（XRD）,热重分析（TGA）对其结构进行表征;采用循环伏安法、恒流充放电和交流阻抗对其电化学性能进行研究. 结果表明：生成的MnO₂均匀地负载在碳的表面,形成多层次结构,并且随着温度的升高IPC表面负载的MnO₂由纳米颗粒变为纳米片状结构;MnO₂纳米片具有典型的K-Birnessite 型晶体结构;复合物中MnO₂的含量约为34%（w）. 在100 ℃制备的IPC/MnO₂复合材料在三电极系统中最高比电容达到了411 F·g^-1;随着反应温度的升高,比容量先增长后基本保持不变. 以IPC/MnO₂为正极,活性炭（AC）为负极,1 mol·L^-1 Na₂SO₄溶液为电解液组装成IPC/MnO₂//AC 混合超级电容器,发现IPC/MnO₂电极的电容器其电位窗口从1 V扩展到1.8 V,容量可达86F·g^-1,且表现出良好的电容特性和大电流放电性能.     

有限域聚合法制备碳纳米管-聚苯胺复合材料及其电化学性能

通过有限域聚合法将聚苯胺(PANI)均匀地生长在碳纳米管(CNTs)表面, 得到CNTs-PANI纳米复合材料. 通过透射电子显微镜(TEM)、扫描电子显微镜(SEM)、傅立叶变换红外(FTIR)光谱对样品的形貌及成分进行表征. 将得到的复合材料组装成电化学超级电容器, 进行电化学的循环伏安和恒流充放电测试. 结果显示, 运用此有限域聚合法所制备的复合材料中PANI 可以非常均匀地包裹在CNTs表面, 复合材料的比容量可以达到117.7 F·g-1(有机电解液), 远远高于所用纯碳纳米管(25.0 F·g-1)和纯聚苯胺(65.0 F·g-1)的比容量, 从而表明有限域聚合法是一良好的纳米复合材料的制备方法.     

Reconstructing Hydrogen Bond Network Enables High Voltage Aqueous Zinc-Ion Supercapacitors

High-voltage aqueous rechargeable energy storage devices with safety and high specific energy are hopeful candidates for the future energy storage system. However, the electrochemical stability window of aqueous electrolytes is a great challenge. Herein, inspired by density functional theory (DFT), polyethylene glycol (PEG) can interact strongly with water molecules, effectively reconstructing the hydrogen bond network. In addition, N, N-dimethylformamide (DMF) can coordinate with Zn²⁺, assisting in the rapid desolvation of Zn²⁺ and stable plating/stripping process. Remarkably, by introducing PEG400 and DMF as co-solvents into the electrolyte, a wide electrochemical window of 4.27 V can be achieved. The shift in spectra indicate the transformation in the number and strength of hydrogen bonds, verifying the reconstruction of hydrogen bond network, which can largely inhibit the activity of water molecule, according well with the molecular dynamics simulations (MD) and online electrochemical mass spectroscopy (OEMS). Based on this electrolyte, symmetric Zn cells survived up to 5000 h at 1 mA cm⁻², and high voltage aqueous zinc ion supercapacitors assembled with Zn anode and activated carbon cathode achieved 800 cycles at 0.1 A g⁻¹. This work provides a feasible approach for constructing high-voltage alkali metal ion supercapacitors through reconstruction strategy of hydrogen bond network.     

Fabrication of MnS/GO/PANI nanocomposites on a highly conducting graphite electrode for supercapacitor application

We demonstrate a high surface area of manganese sulfide (MnS) nanoparticles via a simple solution method and investigated its morphology, physicochemical, and electrochemical studies. For the first time, we attempted to exploit the polymerization of aniline without adding HCl, as it is corrosive to the metal sulfide. Instead, the acidic group present on the graphene oxide surface plays a significant role to some extent as an acidic dopant in the polymerization process. This in-situ polymerization results in the uniform coverage of granular PANI on the entire MnS/GO nanocomposite, which enhances the interfacial interactions between PANI and MnS/GO nanoparticles. The introduction of graphene oxide (GO) to pristine MnS improved the specific capacitance, surface area, and average pore size. And incorporating PANI to MnS/GO leads to an increase in the interfacial interaction between the different pore sized nanoparticles giving enhanced specific capacitance. The specific capacitance for MnS/GO/PANI nanocomposite as measured by galvanostatic charge-discharge measurements was found to be 773 F/g at 1 A/g current density, and even at higher current density, it showed a specific capacitance of 484 F/g at 3.8 A/g. The specific capacitance obtained for MnS/GO/PANI nanocomposite from CV shows 822 F/g at 10 mV/s and 315 F/g at 200 mV/s. The combinatorial effects without destroying the metal sulfide nanostructure can provide an alternate route to design, promising electroactive nanocomposites is an ideal choice as a cost-effective, next-generation high-performance supercapacitor application.     

Hydrothermal Synthesis of NiCo-layered Double Hydroxide Nanosheets Decorated on Biomass Carbon Skeleton for High Performance Supercapacitor

Afacile hydrothermal strategy is adopted to synthesize the composite of NiCo-layered double hydroxide(NiCo-LDH) with biomass carbon as substrate for supercapacitor electrodes. The prepared NiCo@BC was characterized by means of X-ray diffraction(XRD), scanning electronic microscopy(SEM), Fourier transform infrared spectroscopy(FTIR) and Raman spectroscopy, and electrochemical tests. The SEM images demonstrated that numerous NiCo-LDH nanosheets directly grew on the surface of biomass carbon uniformly. Electrochemical tests indicated that the NiCo@BC electrode exhibited good capacitive behavior with a specific capacitance of 606.4 F/g at the current density of 0.5 A/g. In addition, the composite electrode showed excellent cyclic stability of 87.1% even after 1000 cycles. These results manifest that NiCo@BC nanocomposite is a promising candidate for the electrode material for future supercapacitor practical applications.     

基于过渡金属硫化物/还原氧化石墨烯复合物的高性能超级电容器

组装高能量密度的非对称超级电容器需要使用比电容大、 体积变化小且循环稳定性好的电极材料. 过渡金属硫化物(TMSs)与纳米碳材料的复合物是此类电极材料之一. 采用水热法合成了由Cu-Mo硫化物在微波剥离的还原氧化石墨烯表面生长的复合材料(CuS-MoS₂/MErGO). 此复合材料在电流密度为2 A/g时具有高达861.5 F/g的比电容和良好的循环稳定性. 将1.6 V的电池电压施加在由NiS/MErGO为正极, CuS-MoS₂/MErGO为负极组装成的不对称超级电容器上时, 该电容器的功率密度为1.28 kW/kg, 且能量密度保持为54.2 W·h·kg^-1. 结果表明, TMS复合材料是一种很有前途的高性能电化学储能材料, 尤其是用于非对称超级电容器的组装.     

石英晶体微天平分析不同介孔二氧化锰材料的电化学性能

以碳酸锰(MnCO3)为前体,空气氛围下采用不同温度(300℃、350℃、400℃)煅烧, 制备了3种介孔二氧化锰(MnO2)材料,分别与粘结剂混合喷涂至石英晶片作为电极,利用石英晶体微天平(QCM)监测了3种材料在0.1 mol/L Na2SO4溶液中随循环伏安过程的电化学性能变化.分析结果表明,3种材料在首圈循环中都呈现出显著的质量增加,发生了不可逆反应过程; 300℃煅烧制备的MnO2材料具备更好的电化学稳定性和容量保持能力.将300℃, 350℃和400℃煅烧的MnO2各自作为正极与活性炭负极组成超级电容器, 进行充放电测试,首圈均有35％～40％的容量损失; 三者稳定循环时放电容量分别为15.9, 12.9和11.7 mA h/g.QCM的分析与充放电测试结果相一致,表明QCM可用于比较不同介孔二氧化锰材料的电化学性能.