CuCo₂O₄/NiCo-Metal–Organic Framework Nanoflake Arrays for High-Performance Supercapacitors

Abstract

Developing hybrid metal−organic frameworks (MOFs) with ordered structure is significant to obtain promising electrode materials for supercapacitors. Herein, the special electrodes of CuCo 2 O 4 /NiCo-MOF nanoflake vertical arrays are constructed on Ni foam by using the CuCo 2 O 4 nanorods as a selfsacrifice template. Because of the multidirectional interconnected channels of spinel CuCo 2 O 4 , great electrochemical activity of NiCo-MOF, well-arranged morphology, and synergy effect at the interface, the resulting CuCo 2 O 4 /NiCo-MOF nanoflakes exhibit remarkable specific capacity (12.81 F/cm 2 or 1423 F/g at 2 mA/ cm 2 ) and excellent rate performance (remaining 79.2% at 30 mA/ cm 2 ). The asymmetric supercapacitor assembled by CuCo 2 O 4 / NiCo-MOF and an activated carbon electrode shows excellent energy density of 0.48 mWh/cm 2 at a power density of 1.50 mW/cm 2 . This work inspires insight into exploiting hybrid MOFs with highly aligned arrays for energy storage.

Construction of Binder‐Free, Self‐Supported, Hetero‐Core–Shell Honeycomb Structured CuCo2O4@Ni0.5Co0.5(OH)2 with Abundant Mesopores and High Conductivity for High‐Performance Energy Storage

“…Figure 4e exhibits the fine spectrum of Co 2p in CCO@N 0.5 C 0.5 OH/NF; the peaks at 798.08, 796.58, 782.18, and 780.78 eV correspond to Co 2+ 2p 1/2 , Co 3+ 2p 1/2 , Co 2+ 2p 3/2 , and Co 3+ 2p 3/2 , while the two satellite peaks are located at 802.78 and 785.98 eV, respectively. [ 33 ] From the spectra, it can be observed that the content of Co 3+ ions is higher than that of Co 2+ ions, which can be attributed to the presence of Cu atoms that occupy some of the tetrahedral sites of Co 2+ ions, resulting in a relatively higher content of Co 3+ ions in the octahedral sites compared with Co 2+ ions. [ 67 ] Additionally, the binding energy of Co 2p is increased by 0.7 eV after the modification of CCO/NF by anchoring N 0.5 C 0.5 OH.…”

“…The superior electrochemical performance of the CCO@N 0.5 C 0.5 OH/NF electrode may result from the following factors: 1) the porous mesh structure of the NF effectively prevents the aggregation of nanomaterials, reduces the “dead volume” in the electrode, and enhances the utilization rate of the active material. [ 33 ] Additionally, the excellent electrical conductivity of NF promotes efficient electron transfer between the nanomaterials and the current collector, facilitating the redox reaction of the electrode material. [ 22 ] Furthermore, the stable framework structure of NF mitigates mechanical deformation during the charge–discharge process, contributing to the improved cycling stability of the electrode material.…”

“…[32] This unique structure allows for rapid carrier conduction and high electrical conductivity. [33] As an exceptional member of the spinel metal oxide family, CuCo 2 O 4 (CCO) is both nontoxic and inexpensive to produce. [34] The synergistic effect of Co 3+ and Cu 2+ ions in CCO results in significant redox, [35] low electron transfer barriers, [36] and excellent charge storage capacity, [37] making it a highly promising material for constructing high-performance SC electrodes.…”

Sn0.1-Li4Ti5O12/C as a promising cathode material with a large capacity and high rate performance for Mg–Li hybrid batteries

“…[1][2][3][4][5] However, Li resources are limited, and the actual energy density of Li-ion batteries is approaching the technological limit, making the development prospects of traditional Li-ion batteries indistinct. [6][7][8][9][10] Mg is considered one of the options for the generation of energy storage technologies because of its abundance, low price, dendrite-free nature, and higher theoretical volumespecific capacity (3833 mA h cm −3 ) than that of Li (2046 mA h cm −3 ). [11][12][13] However, Mg 2+ has two positive charges, which creates an intense coulombic force between Mg 2+ and the cathode material, resulting in the slow diffusion of Mg 2+ in the cathode material and easy polarization.…”

“…1–5 However, Li resources are limited, and the actual energy density of Li-ion batteries is approaching the technological limit, making the development prospects of traditional Li-ion batteries indistinct. 6–10…”