Vertical crosslinking MoS2/three-dimensional graphene composite towards high performance supercapacitor

The vertical crosslinking MoS₂/three-dimensional graphene composite has been prepared by hydrothermal method, which delivered a superior and stable electrochemical capacitive performance.     

Cysteamine Capped Silver Nanoparticles and Single‐walled Carbon Nanotubes Composite Coated on Glassy Carbon Electrode for Simultaneous Analysis of Hydroquinone and Catechol

A stable complex of silver nanoparticles (Ag NPs) capped by cysteamine (Cst) together with single‐walled carbon nanotube (CNTs) was used to modify a glassy carbon electrode (GCE) for simultaneous detection of hydroquinone (HQ) and catechol (CT). The resulting electrode (AgCst‐CNTs/GCE) showed excellent electrocatalysis and reversibility towards this electroactive pair. The peak separations of their oxidation‐reduction peaks decreased significantly, compared with those of the unmodified GCE. The signal responses of the AgCst‐CNTs/GCE were 5‐fold higher while its peak potential separation remained unchanged (ca. 130 mV), compared to the CNTs‐modified GCE. The oxidation peak currents obtained for HQ and CT exhibited linearly from submicromolar to hundred micromolar concentrations without any cross‐interference. The modified electrode possessed a very large active surface area with a detection limit (S/N=3) of 10 and 40 nM for HQ and CT, respectively. The sensor was demonstrated for the analysis of river water and topical cream as evinced by high accuracy and reproducibility.     

Additive-free porous assemblies of Ti_3C_2T_x by freeze-drying for high performance supercapacitors

Ti_3C_2T_x has shown great potential in energy storage filed,but the restacking between Ti_3C_2T_x nanosheets seriously hampers the maximization of its capacitance.In this study,we rationally designed and synthesized porous Ti_3C_2T_x assemblies without any additive by introducing ice as spacers using a facile freeze-drying method.The porous Ti_3C_2T_x assemblies have a three-dimensional network structure,which consists of ultra large Ti_3C_2T_x lamellar walls and lots of macro-and mesopores.It has been proven that there are more-O groups on the surface of the porous Ti_3C_2T_x assemblies than the Ti_3C_2T_x film.The porous Ti_3C_2T_x assemblies deliver a maximum areal capacitance of 1668 mF/cm2 when the mass loading is 8.4 mg/cm2,an optimized specific capacitance of 247.2 F/g when the mass loading is 5.3 mg/cm2,and87% capacitance retention over 10000 cycles.The symmetric solid-state supercapacitors based on the porous Ti_3C_2T_x assemblies show an areal capacitance of 355.8 mF/cm2,the maximum power density of50 mW/cm2 and an outstanding flexibility under different deformation.     

A novel concept of hybrid capacitor based on manganese oxide materials

A novel asymmetric hybrid capacitor using LiMn₂O₄ and manganese oxide (MnO₂)/carbon nanotube (CNT) nanocomposite as the positive and negative electrode materials, respectively, and 1 M LiClO₄ in propylene carbonate (PC) as the electrolyte has been developed. To the best of our knowledge, this is the first reported assembly of an asymmetric hybrid capacitor with metal oxides for both electrode materials, and, especially, with MnO₂ as the negative electrode material. The discharge profile of the asymmetric hybrid capacitor shows a typical capacitive behavior with a linear slope. The asymmetric hybrid capacitor was able to deliver a specific energy as high as 56 Wh/kg at a specific power of 300 W/kg, based on the total weight of LiMn₂O₄ and MnO₂/CNT nanocomposite in both electrodes. These results clearly demonstrated a superior performance of this new type of capacitor with a higher specific energy compared to other types of asymmetric hybrid capacitors.     

以多层次聚苯胺颗粒为电极活性物质的超级电容器的电化学性能

以(NH₄)₂S₂O₈为氧化剂用化学氧化法合成了具有多层次结构的聚苯胺颗粒，其二次颗粒由一次颗粒集结而成，一次颗粒的粒径基本上在1 μm以下，一次颗粒由多层微小薄片叠合而成. 用这种聚苯胺为活性物质制成电极，以2 mol•L^-1的H₂SO₄水溶液作电解液，组装成了聚苯胺电极超级电容器. 用循环伏安法、电化学阻抗谱和恒电流充放电技术测试了该超级电容器的电化学性能.在7 mA的充放电电流下，它的比能量可达6.35 Wh•kg^-1，比功率可达132 W•kg^-1，电极材料的比容量可达408 F•g^-1. 在20 mA的充放电电流下，它的比能量可达4.39 Wh•kg^-1，比功率可达328 W•kg^-1，电极材料的比容量可达324 F•g^-1. 在100次的充放电循环中，聚苯胺电极超级电容器的电容量没有下降，电荷充放电效率一直保持在95%左右.     

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.     

The effect of the polyaniline morphology on the performance of polyaniline supercapacitors

The polyaniline (PANI) prepared by the pulse galvanostatic method (PGM) or the galvanostatic method on a stainless steel substrate from an aqueous solution of 0.5 mol/l H₂SO₄ with 0.2 mol/l aniline has been studied as an electroactive material in supercapacitors. The electrochemical performance of the PANI supercapacitor is characterized by cyclic voltammetry, a galvanostatic charge–discharge test and electrochemical impedance spectroscopy in NaClO₄ and HClO₄ mixed electrolyte. The results show that PANI films with different morphology and hence different capacitance are synthesized by controlling the synthesis methods and conditions. Owing to the double-layer capacitance and pseudocapacitance increase with increasing real surface area of PANI, the capacitive performances of PANI were enhanced with increasing real surface area of PANI. The highest capacitance is obtained for the PANI film with nanofibrous morphology. From charge–discharge studies of a nanofibrous PANI capacitor, a specific capacitance of 609 F/g and a specific energy density of 26.8 Wh/kg have been obtained at a discharge current density of 1.5 mA/cm². The PANI capacitor also shows little degradation of capacitance after 1,000 cycles. The effects of discharge current density and deposited charge of PANI on capacitance are investigated. The results indicate that the nanofibrous PANI prepared by the PGM is promising for supercapacitors.     

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.     

快速沉淀法制备多孔纳米NiO及其电容性质研究

本文提出一种简单、低成本和无污染的快速沉淀法, 在没有添加任何有机试剂的条件下, 制备了高比表面积并具有良好孔径分布的Ni(OH)2, 于300 ℃下焙烧得到了多孔纳米NiO, 它在2.0 mol/L KOH电解液中的单电极比容量约为255 F/g.     

From interpenetrating polymer networks to hierarchical porous carbons for advanced supercapacitor electrodes

A novel and effective strategy to fabricate hierarchical porous carbons for supercapacitors is developed via in-situ activation of interpenetrating polymer networks obtained from simultaneous polymerization of the monomers for two polymeric networks.