Flower-like FeCoNi ternary composite formed by interweaving nano needles for positive electrode material of supercapacitor

Ternary layered double hydroxide (LDH) are potential electrode material choices for supercapacitors (SCs) due to their various oxidation states and high theoretical specific capacitance. In this paper, FeCoNi-LDH composite with cross-braided flowers of nanoneedles has been prepared by a single-step hydrothermal method. By highlighting the structural and morphological advantages, the obtained ternary LDH shows lower resistivity in comparison with the binary LDH. As electrode material, the ternary LDH exhibits excellent electrochemical properties, such as superb specific capacitance of 2163.3 F·g-1 at 0.5 A·g-1 and good cycle retention rate of 93.8% after 5,000 cycles at 20 A·g-1. Meanwhile, the assembled asymmetric flexible solid-state supercapacitor device can provide 44.8 Wh·kg-1 energy density at 807.5 W·kg-1. Moreover, two devices in series can also light up miniature light bulbs of different hues and maintain them for a long period when they are connected in series.