| Coal and fossil fuel etc gradually consume and produce much pollutant with burning to discharge in the air. Therefore, environmental problem has been increasingly serious. Many researchers pay much attention to the phenomenon that the process of power consumption transfers to power recycle. In the system of power transformation system, pesudocapacitor has been a large potential development that the pseudocapacitors have a higher power density than battery and energy density than double electrode layer supercapacitor. The transition oxides/sulfides have been fabricated from single metal oxides/sulfides to bimetal and ternary metal oxides/sulfides to provide a novel ways to fabricate by the process of electrochemical reaction, which exhibited an excellent electrochemical performance.Mushroom-like Ni3S2 consisting of a thin film on nanorod arrays have been successfully synthesized via a dissolution-precipitation route, which was carried out through a hydrothermal process using the Ni foam in thioacetamide alcohol solution without the introduction of other Ni sources. The thin film, which increases the specific area surface and electrochemical active sites, played a key role in exhibiting an excellent electrochemistry performance of the mushroom-like Ni3S2 electrode. As a pseudocapacitor material, the as-obtained mushroom-like Ni3S2 electrode showed a significant specific capacitance (1190.4 F g-1 at 8 A g-1). Moreover,an asymmetric supercapacitor, with the mushroom-like Ni3S2 as the positive electrode material and activated carbon powder (AC) as the negative electrode material, exhibited a high energy density (60.3 W h kg-1) at an average power density of 3600 W kg-1 based on the mass of the active material.The transition bimetal oxides/sulfides have been extensively investigated and shown to have more excellent energy storage properties than single metal oxides/sulfides, but their low rate performance and poor cycle stability are serious problems in practical applications. We present here a design for the architecture of these electrode materials to fabricate the core-shell hierarchical structures with the aim of improving the rate performance and cycle stability of pseudocapacitors by using an interface ion-exchange method. Such core-shell nanostructure electrode materials can make full use of both components with synergistic effects. Excellent results were obtained with a capacitance of 956.4 F g-1 at a current density of 4 A g-1 in the three-electrode system and an actual energy density of 32.3 W h kg-1 and power density of 1835 W kg-1 in the asymmetrical supercapacitor.Directly inspired by N-doped graphene to transform the chemical bond and band gap width,the Co2Ni3ZnO8 nanowire arrays have been successfully fabricated by the means of interface ion exchange. In addition, the Co2Ni3ZnOs electrode materials, considered as Ni and Zn ions doped into Co3O4. The Co, Ni ions interplay to provide a multi-valence and enhance the electrochemical response capability. After adding the Zn ions, high degree of crystal defect has been provided. Therefore, it has more adsorption site to adsorb the electrolyte ions to storage charge. Hence,the Co2Ni3ZnO8 electrode exhibits a high rate performance and excellent cycle stability after the electrochemical analysis of the relationship between IR drop, Coulomb efficiency,specific capacitance and different current densities. From the results of electrochemical performance the Co2Ni3ZnO8 electrode exhibits a specific capacitance of 1115 F g-1 and retains 89.9% capacitance after 2000 cycles at a current density of 4 A g-1 in the three-electrode system of electrochemical measurement. The energy density of asymmetric supercapacitor (Co2Ni3ZnO8// AC) is 54.04 W h kg-1 at the power density of 3200 W kg-1. |
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