Preparation of CoS supported flower-like NiFe layered double hydroxides nanospheres for high-performance supercapacitors.

Layered double hydroxides (LDHs) are a kind of classic pseudocapacitive materials with lamellar structure and large specific surface area, which have attracted swinging attention in the electrochemical energy storage area. The CoS@Ni is synthesized through a hydrothermal process, followed by surface generation of the flower-like nickel-iron layered double hydroxide (NiFe-LDH) nanospheres through a hydrothermal process, which is directly used to design a binder-free electrode with a splendid capacitance capability. The as-synthesized NiFe-LDH@CoS@Ni electrode presents an outstanding specific capacitance of 11.28 F cm (3880 F g) at 2 mA cm (1.17 A g) in a three electrodes system. Also, the all-solid-state asymmetric supercapacitor (ASC) is combined utilizing the NiFe-LDH@CoS@Ni hybrid as the positive electrodes and active carbon covered Ni foam as negative electrodes, respectively. The as-fabricated ASC exhibits a high energy density of 15.84 Wh kg at the power density of 375.16 W kg and can be able to lighten a blue LED indicator for more than 30 min, revealing that the prepared NiFe-LDH@CoS@Ni owns great potential in the aspect of practical applications. Therefore, the prepared NiFe-LDH@CoS@Ni with outstanding electrochemical properties could be applied for high-performance supercapacitors.