Tailoring the Composition of Ternary Layered Double Hydroxides for Supercapacitors and Electrocatalysis

Abstract

Layered double hydroxides (LDHs) have attracted great consideration in electrochemical systems such as supercapacitors and water splitting due to their layered structures, flexible interlayer distances, and tunable elemental compositions. Recently, ternary LDHs have been considered as efficient materials for energy-related applications due to their superior performance as compared to binary LDHs. To optimize the composition of ternary LDHs for electrochemical applications, herein, Co-, Ni-, and Fe-based ternary LDHs (CNFLs) at different molar ratios are prepared by a facile electrodeposition method. Among them, a sample with a higher concentration of Ni (Ni-rich CNFL) exhibits a maximal specific capacity of 467 C g–¹ at the sweep rate of 5 mV s–¹ with a capacity retention of 81% after 2000 cycles. In the case of electrocatalytic activity, the Ni-rich CNFL shows an appreciable overpotential of 139 mV to reach the current density of 10 mA cm–² along with the smallest Tafel slope (46 mV dec–¹). The Ni-rich CNFL shows excellent electrocatalytic stability over 8 h of stable operation. This enhanced performance of Ni-rich CNFL is attributed to the synergic effect of Co, Ni, and Fe hydroxides and the anticipated growth of more Coᴵⱽ active sites with the higher surface area. Thus, CoNiFe LDH with a high concentration of Ni acts as a potential electrode material for electrochemical applications.