Bifunctional oxygen evolution and supercapacitor electrode with integrated architecture of NiFe-layered double hydroxides and hierarchical carbon framework

NiFe-Coordination Polymers-Derived Layered Double Hydroxides as Bifunctional Materials: Effect of the Ni : Fe Ratio on the Electrochemical Performance

The development of an efficient and cost-effective material is highly desirable for electrochemical devices such as electrolyzers and supercapacitors. Especially, pseudomorphic transformations of metal-organic frameworks (MOFs)/coordination polymers (CPs) into layered double hydroxides (LDHs) materials endow well-defined porosities, high surface area, exchangeable interlayer anions and easily adjustable electronic structure that are truly required for oxygen evolution reaction (OER) and high-performance supercapacitor applications. Herein, we have prepared NiFe-LDHs of various Ni/Fe ratios via a facile room-temperature alkaline hydrolysis of NiFe-CPs precursors. Electrochemical studies reveal that the catalyst having high amount of Fe (Ni1.2 Fe1 -LDH) showed the better OER activity with a low Tafel slope (65 mV dec-1 ) in 1 M KOH. On the other hand, the catalyst containing higher amount of Ni with better layered structure (Ni11.7 Fe1 -LDH) showed high performance for supercapacitor (702 F g-1 at 0.25 A g-1 ) in 3 M KOH. Moreover, a solid-state asymmetric supercapacitor device Ni11.7 Fe1 -LDH/AC was fabricated which exhibited a specific capacitance of 18 F g-1 at a current density of 1 A g-1 . The device displayed high cycling stability with 88% of capacitance retention after 7000 cycles. The experimental findings in this work will help in the futuristic development of NiFe-LDH based electrocatalysts for the enhanced electrochemical performances.

LDH-derived phosphide/N-doped graphene oxide hierarchical electrocatalyst for enhanced oxygen evolution reaction

A hierarchical electrocatalyst Fe-Ni2P/N-GO was successfully synthesized via a facile method combining solvothermal and phosphorization, which shows excellent OER performance in alkaline solution.

Synthesis and Characterisation of Cobalt Ferrite Coatings for Oxygen Evolution Reaction

In this paper, two novel procedures based on powder sedimentation, thermal treatment, and galvanostatic deposition were proposed for the preparation of porous cobalt ferrite (CoFe2O4) coatings with a metallic and organic binder for use as catalysts in the oxygen evolution reaction (OER). The electrochemical properties of the obtained electrode materials were determined as well, using both dc and ac methods. It was found that cobalt ferrite coatings show excellent electrocatalytic properties towards the oxygen evolution reaction (OER) with overpotential measured at a current density of 10 mAcm−2 from 287 to 295 mV and a Tafel slope of 35–45 mVdec−1. It was shown that the increase in the apparent activity of the CoFe2O4 coatings with an organic binder results mainly from a large electrochemically active area. Incorporation of the nickel binder between the CoFe2O4 particles causes an increase in both the conductivity and the electrochemically active area. The Tafel slopes indicate that the same rate-determining step controls the OER for all obtained coatings. Furthermore, it was shown that the CoFe2O4 electrodes exhibit no significant activity decrease after 28 h of oxygen evolution. The proposed coating preparation procedures open a new path to develop high-performance OER electrocatalysts.

The role of nickel–iron based layered double hydroxide on the crystallinity, electrochemical performance, and thermal and mechanical properties of the poly(ethylene-oxide) solid electrolyte

The electrochemical performance and physical properties of PEO-based composite electrolytes were improved with the addition of a NILDH filler.

Tuning the electronic structures of self-supported vertically aligned CoFe LDH arrays integrated with Ni foam toward highly efficient electrocatalytic water oxidation

The developed Ni/CoFe LDH as an anode can provide a current density of 10 mA cm⁻² at 1.532 V vs. RHE, as well as remarkable operational stability, representing the best yet reported noble-metal-free water oxidation electrode.

Highly active hollow mesoporous NiFeCr hydroxide as an electrode material for the oxygen evolution reaction and a redox capacitor

A hollow mesoporous trimetallic NiFeCr hydroxide electrode is prepared via a four-step procedure involving the fast electrodeposition of an Ni/Cr/Fe alloy onto a nickel foam substrate, followed by dealloying, oxidation, and activation. The title electrode shows an ultralow onset overpotential of 210 mV for the oxygen evolution reaction and a high specific capacity of 1768 F g^-1 as a redox capacitor.