Three-Dimensional Core-Branch α-FeO@NiO/Carbon Cloth Heterostructured Electrodes for Flexible Supercapacitors.

A convenient and scalable hydrothermal method was developed for the fabrication of the core-branch FeO@NiO nanorods arrays directly grown on flexible carbon cloth (denoted as FeO@NiO/CC). Such a unique architecture was applied as an electrode of the supercapacitors. As a result, the FeO@NiO/CC exhibited a high areal capacitance ~800 mF cm at 10 mA cm, which was about 10 times increase with respect to FeO nanorods array grown on carbon cloth (FeO/CC). The FeO@NiO/CC also had the long life cycle (96.8 % capacitance retention after 16,000 cycles) and remarkable rate capability (44.0 % capacitance loss at a very large current density of 100 mA cm). The superior performance of the FeO@NiO/CC should be ascribed to the reduction of the contact resistance and the free-standing structure of the flexible electrode. This study provides a novel strategy to construct high-performance flexible electrode materials with unique core-branch structure by incorporating two different pseudocapacitive materials.