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

초록

Layered double hydroxides (LDHs) have attracted great consideration in electrochemical systems such as super-capacitors 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 Co-IV 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.

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