Oriented Nanosheet-Assembled CoNi-LDH Cages with Efficient Ion Diffusion for Quasi-Solid-State Hybrid Supercapacitors

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Fast-charging energy storage is crucial for applications like electric vehicles.
• Hybrid supercapacitors (HSCs) combine capacitor speed with battery energy density.
• Developing advanced materials with high pseudocapacitive activity remains a challenge.

Purpose of the Study:

• To synthesize and characterize a novel material for high-performance HSCs.
• To investigate the potential of metal-organic framework derivatives for energy storage.
• To optimize the structure of cobalt-nickel layered double hydroxide (CoNi-LDH) for enhanced performance.

Main Methods:

• Utilized ZIF-67 as a precursor for CoNi-LDH synthesis via ion exchange.
• Controlled the mass ratio of ZIF-67 to Ni salt to optimize material properties.
• Fabricated HSC devices using the synthesized CoNi-LDH material and a gel electrolyte.

Main Results:

• Synthesized polyhedral CoNi-LDH cages in nanosheet arrays.
• Achieved ultrahigh capacities from 1031.4 to 667.3 C g⁻¹ over a current density range of 1-25 A g⁻¹.
• Demonstrated remarkable energy output of 49 Wh kg⁻¹ and excellent cyclability with minimal decay after 12,000 cycles.

Conclusions:

• The synergistic effect of nanosheet arrays and hollow structures in CoNi-LDH enhances electrochemical performance.
• The developed CoNi-LDH material shows significant promise for advanced energy storage applications.
• This work presents a viable strategy for overcoming limitations in current supercapacitor technology.