3D Hollow Flower‐like CoWO4 Derived from ZIF‐67 Grown on Ni‐foam for High‐Performance Asymmetrical Supercapacitors

A three‐dimensional (3D) hollow CoWO4 composite grown on Ni‐foam (3D−H CoWO4/NF) based on a flower‐like metal‐organic framework (MOF) is designed by utilizing a facile dipping and hydrothermal approach. The 3D−H CoWO4/NF not only possesses large specific areas and rich active sites, but also accommodates volume expansion/contraction during charge/discharge processes. In addition, the unique structure facilitates fast electron/ion transport of 3D−H CoWO4/NF. Meanwhile, a series of characterization measurements demonstrate the appropriate morphology and excellent electrochemical performance of the material. The 3D−H CoWO4/NF possesses a high specific capacitance of 1395 F g−1, an excellent cycle stability with 89% retention after 3000 cycles and superior rate property. Furthermore, the 3D−H CoWO4/NF can be used as a cathode to configurate an asymmetric supercapacitor (ASC), and 3D−H CoWO4/NF//AC shows a good energy density (29.0 W h kg−1). This work provides a facile method for the preparation of 3D‐hollow electrode materials with high electrochemical capability for advanced energy storage devices.