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Traditional asymmetric supercapacitors are severely restricted due to the low specific capacitance of carbon negative materials. The rational design of positive and negative electrodes that afford the asymmetric device with high performances is particularly important. In this paper, we fabricate a novel cost-effective and environmental-friendly aqueous asymmetric supercapacitor by using CuCo 2 O 4 /CuO nanowire arrays as positive electrode and RGO/Fe 2 O 3 composites as negative electrode. The assembled device exhibits a high energy density of 33.0 Wh kg -1 at a power density of 200 W kg -1 , and can still operate at a high power density of 8.0 KW kg -1 with an energy density of 9.1 Wh kg -1 . The current strategy will provide a fresh route for design and fabricate of novel asymmetric supercapacitors with both high energy density and high power density.

In this study, nanocrystals of a cerium-based metal–organic framework (Ce-MOF), Ce-MOF-808, are directly grown on the surface of carboxylic acid-functionalized carbon nanotubes (CNTs) by a facile one-step solvothermal synthesis method. Ce-MOF–CNT nanocomposites with various Ce-MOF-to-CNT ratios are synthesized, and their crystallinity, morphology, porosity, and electrical conductivity are examined. The redox-hopping and electrochemical behaviors of the pristine Ce-MOF in aqueous electrolytes are investigated, suggesting that the pristine Ce-MOF is electrochemically active but possesses a limited charge-transport behavior. As a demonstration, all the Ce-MOF, CNT, and nanocomposites are used as active materials for application in aqueous-based supercapacitors. The capacitive performance of the CNT can be significantly boosted with the help of redox-active Ce-MOF-808 nanocrystals.

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A NiCo2S4@Ni3V2O8//AC asymmetric supercapacitor was successfully fabricated and it can deliver both high energy density and high power density.