In Situ Growth of Ultrathin NiO Nanosheet‐Arrays on MOF‐Derived Porous Co3O4 Scaffolds as High‐Performance Cathode for Asymmetric Supercapacitors

Abstract

AbstractThe ever‐increasing market for portable and wearable electronic devices creates a demand for high‐efficiency electrochemical energy storage devices with excellent flexibility. Herein, MOF‐derived porous Co3O4 scaffolds as the core, ultrathin NiO nanosheet‐arrays as the shell, well‐aligned core‐shell structured Co3O4@NiO were constructed on carbon cloth (CC/Co3O4@NiO) via facile chemical bath methods. Composition, morphological structure, and electrochemical performance of the hybrid nanomaterials were analyzed in detail. Benefiting from the MOF‐derived porous Co3O4 core, the NiO shell with large specific surface area, and close conductive linkages between the core and shell, CC/Co3O4@NiO presents an outstanding areal capacitance of 3015.1 mF cm−2 (1206 F g−1) at 5 mA cm−2 and an exceptional rate performance. Additionally, the flexible SASC device assembled with the CC/Co3O4@NiO cathode possesses an ultra‐high volumetric energy density of 3.11 mWh cm−3 at a volumetric power density of 116 mW cm−3 with a satisfactory cycling stability (90.1 % of after 10000 cycles). These values are superior to the great majority of the state‐of‐the‐art flexible electrochemical capacitors. Thereby, the core‐shell structured CC/Co3O4@NiO is a promising candidate material for energy storage devices, and this work can provide a reference for the structural design and constructing of electrode materials.