Three dimensional integrated architecture of Sr-Fe LDH on hierarchical NiS framework as a flexible electrode for efficient energy storage and conversion applications

摘要

It is vital to examine the abundance of non-precious transition metal di-chalcogenides (TMDs) and layered double hydroxides (LDH) with greater storage capability and excellent electrocatalytic activity. Nowadays, the robust coupling of TMDs and LDH based materials emerged as an efficient electrocatalyst for significant electrochemical applications. The binder-free, flexible, bi-functional catalysts, 3D hybrid nanostructures of coupled TMDs/LDH on the carbon cloth (CC) electrode substrate. Initially, the hierarchical NiS nanoflowers were self assembled on a flexible CC substrate via hydrothermal approach. Herein, the Sr-Fe LDH nanosheets are vertically anchored on high conductive and flexible NiS/CC electrodes without destroying the original architecture by the electrodeposition method. This enriched 3D hybrid NiS@ Sr-Fe OH/CC nanostructure provides enormous nucleation active sites with interconnected layers leading to the enhancement of electrocatalytic behaviour. The outstanding structural and morphological advantages accelerate the electrochemical activities and reaction kinetics of prepared NiS/CC, Sr-Fe OH/CC and NiS@ Sr-Fe OH/CC flexible electrode based supercapacitor exhibits the specific capacitance of 556, 1151 and 1553 F g-1 at 1 A g-1 current density respectively. NiS@ Sr-Fe OH/CC//AC/CC device has a favourable energy density of 53.07 Wh kg-1 at a high power density of 4.4 kW kg-1. Additionally, these 3D flexible hybrid electrodes also favour oxygen evolution reaction at an extremely lower overpotential (n) of 131 mV @ 10 mA cm-2 current density with a Tafel slope of 53 mV dec- 1. The electrodeposited NiS@ Sr-Fe OH/CC electrodes exhibit a bi-functional catalyst with better performance due to their greater surface area of 76.304 m2 g-1, pore volume of 0.113 nm, fast electron transfer kinetic, hierarchical nanostructures and function as a promising candidate for future energy storage and conversion applications.