المؤلفون: Ming Li, Wen-Qiang Chen, Shiming Gao, Pei-Bin Zhang, Songhao Guo, Fumin Liu, Jipeng Cheng

المصدر: Journal of Colloid and Interface Science. 555:284-293

مصطلحات موضوعية: Supercapacitor, Materials science, Composite number, chemistry.chemical_element, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Capacitance, Energy storage, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Biomaterials, Colloid and Surface Chemistry, chemistry, Chemical engineering, Phase (matter), Electrode, 0210 nano-technology, Ternary operation, Cobalt

الوصف: Developing safe, efficient and environment-friendly energy storage systems continues to inspire researchers to synthesize new electrode materials. Doping or substituting host material by some guest elements has been regarded as an effective way to improve the performance of supercapacitors. In this work, single-phase CuCo2−xNixS4 materials were synthesized by a facile two-step hydrothermal method, where Co in CuCo2S4 was substituted by Ni. Cobalt could be easily substituted with Ni in a rational range to keep its constant phase. But, a high content of Ni resulted in a multi-phase composite. Among a series of CuCo2−xNixS4 materials with different Ni/Co mole ratios, CuCo1.25Ni0.75S4 material presented a significantly high specific capacitance (647 F g−1 or 272 C g−1 at 1 A g−1) and the best cycling stability (∼98% specific capacitance retention after 10,000 charge-discharge cycles), which was mainly due to the modified composition, specific single phase, higher electroconductivity, more electroactive sites and the synergistic effect between Ni and Co. Moreover, the assembled asymmetric capacitor using CuCo1.25Ni0.75S4 as a positive electrode and activated carbon as a negative electrode delivered a high energy density of 31.8 Wh kg−1 at the power density of 412.5 W kg−1. These results demonstrated that ternary metal sulfides of CuCo2−xNixS4 are promising electrode materials for high-performance supercapacitors.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_________::b902ac4db27a6e9823578dcfb86101b8Test
https://doi.org/10.1016/j.jcis.2019.07.091Test

المؤلفون: Songhao Guo, Wen-Qiang Chen, Jipeng Cheng, Min Li, Fu Liu, Suqin Gao, Jiao Wang, Jiangwei Wang, Pengwei Yuan

المصدر: Journal of Electroanalytical Chemistry. 836:134-142

مصطلحات موضوعية: Supercapacitor, Chemistry, General Chemical Engineering, 02 engineering and technology, Crystal structure, 010402 general chemistry, 021001 nanoscience & nanotechnology, Electrochemistry, Microstructure, 01 natural sciences, 0104 chemical sciences, Analytical Chemistry, Metal, Crystal, Crystallinity, Chemical engineering, visual_art, visual_art.visual_art_medium, 0210 nano-technology, Solid solution

الوصف: A series of mixed metal sulfides of NixCu1−xCo2S4 were synthesized by a facile two-step hydrothermal method and they were investigated as electrode materials for supercapacitor. A substitutional solid solution can be easily formed due to the same atom occupation and similar crystal radius of Ni and Cu in the metal sulfides. The electrochemical performances of the mixed metal sulfides are strongly influenced by the chemical compositions, though they have the same crystal structure. Among all the as-prepared materials, Ni0.67Cu0.33Co2S4 shows the best electrochemical performances with the highest specific capacitance of 1340.48 F g−1 at 1 A g−1, outstanding rate capability and excellent cycling stability. The improved performances can be attributed to the high crystallinity, modified microstructure, increased electrochemical sites and improved electroconductivity caused by lattice distortion as well as the synergistic effect in the Cu-substituted NiCo2S4. Furthermore, the assembled two-electrode hybrid device Ni0.67Cu0.33Co2S4//activated carbon can deliver a high energy density of 40 Wh kg−1 at the power density of 412.5 W kg−1, showing a great potential for energy storage.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_________::299a3fe40ac01ec9a1ca668cbbb050faTest
https://doi.org/10.1016/j.jelechem.2019.02.003Test

المؤلفون: Jipeng Cheng, Fujian Liu, S.Q. Gao, Songhao Guo, Wen-Qiang Chen

المصدر: Electrochimica Acta. 286:14-21

مصطلحات موضوعية: Supercapacitor, Materials science, General Chemical Engineering, Sulfidation, chemistry.chemical_element, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Capacitance, Sodium sulfide, 0104 chemical sciences, Crystallinity, chemistry.chemical_compound, chemistry, Chemical engineering, Electrode, Electrochemistry, Hydroxide, 0210 nano-technology, Cobalt

الوصف: Low crystalline CoSx was fabricated by anion-exchange of 2-dimensional (2D) cobalt carbonate hydroxide (CoCH) using aqueous sodium sulfide solution at room temperature. It was proved that single crystalline CoCH nanoplates would transform into porous 2D CoSx with low crystallinity after the anion-exchange. When they were used as electrode materials for supercapacitor, the 2D CoSx material had a much higher specific capacitance than its precursor due to their different compositions and electroconductivities. CoSx had a high specific capacitance of 863 F g−1 at 1 A g−1 and a good stability during long time charge-discharge processes, about 64.7% of initial capacitance retention after 10000 cycles. Asymmetric hybrid devices using 2D CoSx as positive electrode and activated carbon as negative electrode were assembled, and the capacitor devices were able to achieve a high energy density of 33.56 Wh kg−1 at the power density of 400 W kg−1. The high performances of the porous CoSx make it a promising electrode material for energy storage.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_________::942f75f7fba91a7807e7f0d3ddb72fa3Test
https://doi.org/10.1016/j.electacta.2018.08.035Test

المؤلفون: Jiao Wang, Meixun Li, Fujian Liu, Jipeng Cheng, WenQiang Chen, Songhao Guo, K.Y. Ma

المصدر: Applied Surface Science. 451:280-288

مصطلحات موضوعية: Supercapacitor, Materials science, Nanowire, General Physics and Astronomy, Heterojunction, 02 engineering and technology, Surfaces and Interfaces, General Chemistry, Substrate (electronics), 010402 general chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Electrochemistry, 01 natural sciences, Capacitance, Hydrothermal circulation, 0104 chemical sciences, Surfaces, Coatings and Films, law.invention, Chemical engineering, law, Calcination, 0210 nano-technology

الوصف: In this work, hierarchical NiCo2O4@Co-Fe layered double hydroxide (LDH) core-shell nanowire arrays on Ni foam were synthesized by facile hydrothermal and calcination methods. The pre-formed NiCo2O4 nanowires on Ni foam acted as a substrate and then guided the deposition of Co-Fe LDH nanoflakes on their surface to form a highly porous hierarchical core–shell heterostructure. Meanwhile, NiCo2O4 nanowires and Co-Fe LDH nanoflake films were also deposited on Ni foam. The materials were well characterized and used for electrochemical energy storage. The unique core-shell configuration of NiCo2O4@Co-Fe LDH can make full use of the synergistic effects of two components, provide sufficient electroactive sites as well as facilitate the charge transportation process. The as-prepared NiCo2O4@Co-Fe LDH nanowire arrays displayed outstanding electrochemical performances with a high specific capacitance of 1557.5 F g−1 at 1 A g−1. The assembled two-electrode hybrid device NiCo2O4@Co-Fe LDH//activated carbon could deliver an energy density of 28.94 Wh kg−1 at the power density of 950 W kg−1, showing a promising potential in energy storage and conversion.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_________::5d773de7979ed092c364747255788cd7Test
https://doi.org/10.1016/j.apsusc.2018.04.254Test

المؤلفون: Jipeng Cheng, Fujian Liu, Wen-Qiang Chen, Songhao Guo, Jun Wang, M. Li

المصدر: Electrochimica Acta. 271:498-506

مصطلحات موضوعية: Supercapacitor, Materials science, General Chemical Engineering, Sulfidation, chemistry.chemical_element, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Cobalt sulfide, Hydrothermal circulation, 0104 chemical sciences, Amorphous solid, chemistry.chemical_compound, Crystallinity, chemistry, Chemical engineering, Electrode, Electrochemistry, 0210 nano-technology, Cobalt

الوصف: Amorphous and crystalline copper cobalt sulfides are successfully synthesized via a hydrothermal method at different temperatures and researched as electrode materials for supercapacitor. The reaction mechanisms during the sulfidation and hydrothermal processes are investigated and clarified. It is demonstrated that the hydrothermal temperature is a crucial factor for the crystallinity, morphology and electrochemical performance of CuCo2S4. Among all the samples, the CuCo2S4 synthesized at 150 °C shows the highest specific capacitance of 515 F g-1 at 1 A g−1 as well as good cycling stability with ∼93.3% capacitance retention after 10000 cycles at 5 A g−1. An asymmetric device which is assembled by using optimized CuCo2S4 electrode as positive electrode and activated carbon as negative electrode material is able to deliver an ultrahigh energy density of 50.56 Wh kg−1 at a power density of 4.6 kW kg−1, and remains 20.93 Wh kg−1 at a high power density of 22.5 kW kg−1, with ∼99% capacity retention after 10000 cycles. Based on the results above, the CuCo2S4 materials prepared by our method possess a considerable potential as electrode materials for supercapacitor applications.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_________::77d6e2d01f6c001913692bd38515897bTest
https://doi.org/10.1016/j.electacta.2018.03.189Test

المؤلفون: Pengwei Yuan, Songhao Guo, Fu Liu, Jipeng Cheng, Min Li

المصدر: International Journal of Hydrogen Energy. 42:28797-28806

مصطلحات موضوعية: Supercapacitor, Materials science, Renewable Energy, Sustainability and the Environment, Layered double hydroxides, Energy Engineering and Power Technology, 02 engineering and technology, engineering.material, 010402 general chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Electrochemistry, 01 natural sciences, Capacitance, 0104 chemical sciences, Fuel Technology, Chemical engineering, Electrode, medicine, engineering, 0210 nano-technology, Porosity, Activated carbon, medicine.drug, Power density

الوصف: The development of electrode materials with hierarchically porous structure and high electrochemical stability is crucial for the electric energy density of supercapacitors. Hollow microspheres of Ni-Co layered double hydroxides (LDHs) and Ni-Mn LDHs are fabricated with a simple co-precipitation method at low temperature using SiO2 microspheres as a sacrifice template. The as-fabricated two LDH hollow microspheres possess a unique 3D architecture and exhibit high specific capacitance, as well as excellent rate and cycling performances as electrode materials of supercapacitors. A specific capacitance of 1766.4 F g−1 at 1 A g−1 is achieved for Ni-Co LDHs electrode, much higher than that of Ni-Mn LDHs. A hybrid capacitor composed of Ni-Co LDHs hollow spheres and activated carbon is fabricated and evaluated for practical application, providing an energy density of 44.3 Wh kg−1 at a power density of 0.425 kW kg−1. This study indicates that the hollow LDH microsphere prepared by our method is a promising material for supercapacitors.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_________::594024f1cb04de5cefef356f9a1b35eeTest
https://doi.org/10.1016/j.ijhydene.2017.10.019Test