Highly Stable Two-Dimensional Cluster-Based Ni/Co–Organic Layers for High-Performance Supercapacitors

Abstract

Basic requirements for advanced and practical supercapacitors need electrode materials with strong stability, high surface area, well-defined porosity, and enhanced capability of ion insertion and electron transfer. It is worth mentioning that the two-dimensional cluster-based Ni/Co−organic layer (Ni 0.7 Co 0.3 -CMOL) inherits high stability from the Kagoḿe lattice and shows excellent pseudocapacitance behavior. As an optimized atomic composition, this crystalline CMOL exhibits excellent performance and stability both in 1.0 M KOH and All-Solid-State Flexible Asymmetric Supercapacitor (ASCs). The specific capacitance values are 1211 and 394 F g −1 and the energy density is 54.67 Wh kg −1 at 1 A g −1 . Good cycling stability is characterized by its capacitance retention, maintained at 92.4% after 5000 cycles in a three-electrode system and 90% after 2000 cycles at 20 A g −1 for assembled All-Solid-State Flexible ASCs. An in situ XRD technique was used in the three-electrode system, which showed that there was no signal of crystalline substance that affected the cyclic stability of the material while charging and discharging. These superior results prove that Ni 0.7 Co 0.3 -CMOL is a promising candidate for supercapacitor applications.

Self-Assembled Cobalt–Nickel Bimetallic-Organic Framework Materials with High Supercapacitor Performance

“…Furthermore, the Co 2.75 Ni 1 -MOF//AC device can retain 85.4% of the initial capacitance over 15,000 cycles at 4 A g –1 (Figure c). Its high cycling stability can be imputed to interfacial activity completely and the surface hydrolysis of Co 2.75 Ni 1 -MOF in an alkaline medium. , Similarly, there is little deformation in the trend within the GCD tests of the first 10 turns and last 10 turns, implying the high stability of hybrid devices.…”

Self-Reconstructed Two-Dimensional Cluster-Based Co–Organic Layer Heterojunctions for Enhanced Oxygen Evolution Reactions

“…Crystal Structure. The Kagoḿe crystal lattice was first reported by Niu's group 42 and a few research projects had developed on this structure, like high-performance supercapacitors, 41 efficient lithium storage, 43 and electrocatalytic oxygen evolution. 44 with the described structural evolution process.…”

“…The band around 745 cm −1 is associated with ortho substitution of benzene. 49,50 The different bands at 3595 and 3630 cm −1 , the former for the μ 3 -OH 41 and the latter for the O−H 51,52 stretching mode, which is indicative of free OH groups in β-Co(OH) 2 , are among the variations between the 51 Raman spectroscopy provides more sensitive information and insights into the structural evolution process (Figure 2c) so that we can tell the difference between the Co-MOF and State 1. Referring to State 2, a brand new peak appears at 506 cm −1 , which is attributable to the A 2u vibration peak of β-Co(OH) 2 , which determines the creation of β-Co(OH) 2 and the preservation of the properties of Co-MOF itself.…”

“…The Kagóme crystal lattice was first reported by Niu’s group and a few research projects had developed on this structure, like high-performance supercapacitors, efficient lithium storage, and electrocatalytic oxygen evolution Figure S3 illustrates the crystal structure and divides it into three sections: the layer structure, the Kagóme lattice, and the coordination environment of the Co (cobalt) ion.…”

“…The Co-MOF was synthesized with reference to our previous work. 41 Inside a 150 mL Teflon-lined stainless-steel autoclave, there was a mixture of 6.0 mmol CoCl 2 • 6H 2 O, 6.0 mmol 1,2-H 2 bdc, 4.8 mmol 2,4-diamino-6-phenyl-1,3,5triazine (phdat), and 120 mL of H 2 O. After sealing the autoclave, it was placed into a 180 °C drying oven and maintained for 2 days.…”