Controllable Transformation of Metal–Organic Framework Nanosheets into Oxygen Vacancy Ni_xCo_3–xO₄ Arrays for Ultrahigh-Capacitance Supercapacitors with Long Lifespan

Abstract

The amino-functionalized bimetal NH2-NiCo-MOF nanosheet array is first fabricated on Ni foam substrates and then controllably transformed into oxygen vacancy bimetal oxide arrays by simply thermal annealing in air. This NiCo-based oxide array (Ni x Co3–x O4/NF) achieves high capacitance (2484 F g–1 at 1 A g–1), excellent rate performance (91.4%), and long cycling life when assessed as promising electrode material for supercapacitors. Notably, the existing oxygen vacancy in Ni x Co3–x O4 promotes the electrochemical performance of Ni x Co3–x O4/NF due to the enhancement of electrical conductivity and capture capability for OH–. In addition, the assembled asymmetric supercapacitor (ASC) device exhibits an excellent energy density of 39.3 W h kg–1 at a power density of 800.2 W kg–1, which still remains 32.2 W h kg–1 even at a high power density of 7994.5 W kg–1. Furthermore, a light-emitting diode can be lightened for more than 6 min, demonstrating a great potential for practical application of ASC devices. This work knocks on the door of a feasible strategy for designing and synthesizing 2D metal oxide nanosheet arrays with excellent electrochemical properties.

Dual Functionality of Dichalcogenide-Supported Pentagon Core–Hexagon Ring-Structured NiCo2O4 Nanoplates: An Effective Hybridization for Tuning of a Diffused- to a Surface-Controlled Process and Boosting of CO2 Electrocatalysis

“…The ASC device renders an enhanced specific energy value of 68.9 W h kg –1 at a specific power of 1.28 kW kg –1 at a current density of 1 A g –1 . The E and P values of the NiCo 2 O 4 /MoSe 2 //AC device are superior to those of different ASC devices reported previously based on NiCo 2 O 4 and its composites such as NiCo 2 O 4 //AC (24.5 W h kg –1 and 175 W kg –1 ), NiCo 2 O 4 /carbon cloth//porous graphene paper [(32.9 W h kg –1 and 970.1 W kg –1 ), NiCo 2 O 4 /NiCoSe/nickel foam (NF)//AC (54.5 W h kg –1 and 350 W kg –1 ), NiCo 2 O 4 //AC cocoa-700 (47.7 W h kg –1 and 430 W kg –1 ), Ni x Co 3– x O 4 /NF//AC (39.3 W h kg –1 and 800.2 W kg –1 ), NiCo 2 O 4 –S@graphdiyne and AC (62.8 W h kg –1 and 747.9 W kg –1 ), Vo-NiCo 2 O 4 @carbon cloth-16 h//AC@C (43.6 W h kg –1 and of 281 W kg –1 ), and NiCo 2 O 4 –rGO//rGO (67.89 W h kg –1 and 1 kW kg –1 ) . The cyclic stability of the ASC device (Figure h) is examined up to continuous 10,000 GCD cycles at a current density of 30 A g –1 , and it withstands 95% of the initial capacitance at the end GCD cycle.…”

“…Moreover, nonnoble metals have drawn more interest for supercapacitors and CO 2 electro-reduction reactions. Single or mixed transition metal oxides with stoichiometric or non-stoichiometric structures have recently been paid more attention in energy storage 9 and electrocatalysis application 10 due to their excellent electrochemical properties, low cost, and eco-friendly nature. In this regard, spinel (AB 2 O 4 )-structured NiCo 2 O 4 was found to be a significant bifunctional material for supercapacitors and CO 2 electro-reduction reactions since it satisfies the aforementioned perquisites.…”

“…−1 . The E and P values of the NiCo 2 O 4 /MoSe 2 //AC device are superior to those of different ASC devices reported previously based on NiCo 2 O 4 and its composites such as NiCo 2 O 4 //AC (24.5 W h kg −1 and 175 W kg −1 ),60 NiCo 2 O 4 /carbon cloth//porous graphene paper [(32.9 W h kg −1 and 970.1 W kg −1 ),61 NiCo 2 O 4 /NiCoSe/ nickel foam (NF)//AC (54.5 W h kg −1 and 350 W kg −1 ),62 NiCo 2 O 4 //AC cocoa-700 (47.7 W h kg −1 and 430 W kg −1 ),63 Ni x Co 3−x O 4 /NF//AC (39.3 W h kg −1 and 800.2 W kg −1 ),9 …”

One-Step Solvothermal Synthesis of Raspberry-like NiCo-MOF for High-Performance Flexible Supercapacitors for a Wide Operation Temperature Range

“…Five elements, namely, C, N, O, Co, and Ni, are present on NiCo-MOF-3. The content of these elements varies with O, Co, and Ni predominating; nevertheless, all the five elements are evenly distributed on it, with no one location being particularly prominent and other locations loading tiny elements …”

“…The content of these elements varies with O, Co, and Ni predominating; nevertheless, all the five elements are evenly distributed on it, with no one location being particularly prominent and other locations loading tiny elements. 28 The N 2 adsorption−desorption isotherms and pore size distributions of NiCo-MOF-1/2/3/4 are demonstrated in Figure S1a−d. It is observed that all their adsorption− desorption isotherms are primely consistent with H3 hysteresis returns (type IV), proving their mesoporous laminar structures with commendable specific surface areas.…”