This work presents NiS/graphene/carbon nanotube （NiS/GNS/CNT） composites as electrode material for the supercapacitor application in sea flashing signal systems. NiS nanosheets were closely anchored on the conductiv...This work presents NiS/graphene/carbon nanotube （NiS/GNS/CNT） composites as electrode material for the supercapacitor application in sea flashing signal systems. NiS nanosheets were closely anchored on the conductive GNS-CNT networks. As a result, the NiS/GNS/CNT electrode showed a high specific capacitance of 2 377 F.g^-1 at 2 mV.s^-1 and good cycling stability compared with the pure NiS （1 599F.g^-1）. The enhanced electrochemical performances are attributed to the synergetic effect between the conductive carbon and the pseudo-capacitive NiS. The high performance supercapacitor may provide application in the sea flashing signal system.展开更多
Nanostructured Mn3O4 was introduced to activated C （AC） by a novel sonochemical reaction, and the resulting nanocomposites were examined as supercapacitor electrodes. The sonication not only catalyzed the redox reac...Nanostructured Mn3O4 was introduced to activated C （AC） by a novel sonochemical reaction, and the resulting nanocomposites were examined as supercapacitor electrodes. The sonication not only catalyzed the redox reaction but also promoted the diffusion of the precursors, causing the formation of coherent nanocomposites with Mn3O4 nanoparticles grown and uniformly distributed inside the mesopores of the AC. In addition, the extreme local condition in the sonochemical synthesis yielded an excessive amount of divalent manganese ions and oxygen vacancies. This novel microstructure endowed the sample with a superior performance, including a specific capacitance of 150 F/g compared with the value of 93 F/g for AC at a charge/discharge rate of 100 mA/g. A Li-ion capacitor delivered an energy density of 68 Wh/kg, compared with 41 Wh/kg for the AC capacitor at a power density of 210 W/kg.展开更多
MnO2/carbon nanocomposites with hierarchical pore structure and controllable MnO2 loading have been synthesized using a self-limiting growth method. This was achieved by the redox reactions of KMnO4 with sacrificed ca...MnO2/carbon nanocomposites with hierarchical pore structure and controllable MnO2 loading have been synthesized using a self-limiting growth method. This was achieved by the redox reactions of KMnO4 with sacrificed carbon substrates that contain hierarchical pores. The unique pore structure allows the synthesis of nanocomposites with tunable MnO2 loading up to 83 wt.%. The specific capacitance of the nanocomposites increased with the MnO2 loading; the conductivity measured by electrochemical impedance spectroscopy, on the other hand, decreased with increasing MnO2 loading. Optimization of the MnO2 loading resulted in nanocomposites with high specific capacitance and excellent rate capability. This work provides important fundamental understanding which will facilitate the design and fabrication of high-performance supercapacitor materials for a large variety of applications.展开更多
Electrochemical ion exchange has been used to tailor the composition of transition metal oxides （Co3O4） electrode with enhanced capacity while maintaining its crystal structure and morphology. Specifically, Ni ions ...Electrochemical ion exchange has been used to tailor the composition of transition metal oxides （Co3O4） electrode with enhanced capacity while maintaining its crystal structure and morphology. Specifically, Ni ions were incorporated to C03O4 nanosheets sandwiched by nanoneedles to form Co3O4/NiCo2O4 composite. As positive electrode for supercapacitors, the Co3O4/NiCo2O4 composite presents a high areal capacitance of 3.2 F cm^-2 （1060 F g^-1） at a current density of 5 mA cm^-2 and outstanding rate capability as well as long cycle stability. Moreover, the assembled aqueous asymmetric supercapacitor based on Co3O4/NiCo2O4//carbon cloth electrodes delivers a considerable energy density of 3.0 mW hcm^-3 at power density of 136 mW cm^-3, and high rate capability （85% retention at a current density of 30 mA cm^-2）. A safety light composed of ten green LEDs in parallel was lit for -360 s using two identical supercapacitors in series, indicating a promising practical application.展开更多
基金Foundation item： Supported by the National Natural Science Foundation of China （Nos. 51077014, 21003028 and 51202043）： the Fundamental Research funds for the Central Universities, the Program for New Century Excellent Talents in University （NCET-10-0050）, and the Excellent Youth Foundation of Heilongjiang Province of China.
文摘This work presents NiS/graphene/carbon nanotube （NiS/GNS/CNT） composites as electrode material for the supercapacitor application in sea flashing signal systems. NiS nanosheets were closely anchored on the conductive GNS-CNT networks. As a result, the NiS/GNS/CNT electrode showed a high specific capacitance of 2 377 F.g^-1 at 2 mV.s^-1 and good cycling stability compared with the pure NiS （1 599F.g^-1）. The enhanced electrochemical performances are attributed to the synergetic effect between the conductive carbon and the pseudo-capacitive NiS. The high performance supercapacitor may provide application in the sea flashing signal system.
基金This work was supported by the ＂Thousands Talents＂ Program for Pioneer Researcher and His Innovation Team, China. This work was also supported by the National Natural Science Foundation of China （No.51374029）, Program for New Century Excellent Talents in University （No. NCET-13-0668）, Fundamental Research Funds for the Central Universities （No. FRF-TP-14-008C1） and China Postdoctoral Science Foundation （No. 2014M550675）.
文摘Nanostructured Mn3O4 was introduced to activated C （AC） by a novel sonochemical reaction, and the resulting nanocomposites were examined as supercapacitor electrodes. The sonication not only catalyzed the redox reaction but also promoted the diffusion of the precursors, causing the formation of coherent nanocomposites with Mn3O4 nanoparticles grown and uniformly distributed inside the mesopores of the AC. In addition, the extreme local condition in the sonochemical synthesis yielded an excessive amount of divalent manganese ions and oxygen vacancies. This novel microstructure endowed the sample with a superior performance, including a specific capacitance of 150 F/g compared with the value of 93 F/g for AC at a charge/discharge rate of 100 mA/g. A Li-ion capacitor delivered an energy density of 68 Wh/kg, compared with 41 Wh/kg for the AC capacitor at a power density of 210 W/kg.
文摘MnO2/carbon nanocomposites with hierarchical pore structure and controllable MnO2 loading have been synthesized using a self-limiting growth method. This was achieved by the redox reactions of KMnO4 with sacrificed carbon substrates that contain hierarchical pores. The unique pore structure allows the synthesis of nanocomposites with tunable MnO2 loading up to 83 wt.%. The specific capacitance of the nanocomposites increased with the MnO2 loading; the conductivity measured by electrochemical impedance spectroscopy, on the other hand, decreased with increasing MnO2 loading. Optimization of the MnO2 loading resulted in nanocomposites with high specific capacitance and excellent rate capability. This work provides important fundamental understanding which will facilitate the design and fabrication of high-performance supercapacitor materials for a large variety of applications.
基金supported by the National Natural Science Foundation of China (61376011)Gansu Provincial Natural Science Foundation of China (17JR5RA198)the Fundamental Research Funds for the Central Universities (lzujbky-2017-k21)
文摘Electrochemical ion exchange has been used to tailor the composition of transition metal oxides （Co3O4） electrode with enhanced capacity while maintaining its crystal structure and morphology. Specifically, Ni ions were incorporated to C03O4 nanosheets sandwiched by nanoneedles to form Co3O4/NiCo2O4 composite. As positive electrode for supercapacitors, the Co3O4/NiCo2O4 composite presents a high areal capacitance of 3.2 F cm^-2 （1060 F g^-1） at a current density of 5 mA cm^-2 and outstanding rate capability as well as long cycle stability. Moreover, the assembled aqueous asymmetric supercapacitor based on Co3O4/NiCo2O4//carbon cloth electrodes delivers a considerable energy density of 3.0 mW hcm^-3 at power density of 136 mW cm^-3, and high rate capability （85% retention at a current density of 30 mA cm^-2）. A safety light composed of ten green LEDs in parallel was lit for -360 s using two identical supercapacitors in series, indicating a promising practical application.
