Layered Double Hydroxide Hollowcages with Adjustable Layer Spacing for High Performance Hybrid Supercapacitor

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Layered double hydroxides (LDHs) show promise for supercapacitors due to tunable properties and high theoretical capacity.
• Limited experimental capacity in LDHs stems from small interlayer spacing, hindering ion diffusion.
• Expanding interlayer spacing is crucial for enhancing LDH performance in energy storage devices.

Purpose of the Study:

• To design and fabricate novel cobalt-nickel layered double hydroxide hollow cages.
• To improve the specific capacity and rate performance of LDH electrodes.
• To investigate the effect of 1,4-benzenedicarboxylic acid (H2BDC) intercalation on LDH structure and electrochemical properties.

Main Methods:

• Fabrication of metal-organic framework derived cobalt-nickel layered double hydroxide hollow cages.
• In-situ cationic etching and organic ligand intercalation using varying concentrations of H2BDC.
• Electrochemical characterization of LDH electrodes and hybrid supercapacitors.

Main Results:

• The intercalation of H2BDC successfully increased the interlayer spacing of the LDH hollow cages.
• The LDH sample with the largest interlayer spacing achieved a maximum specific capacity of 229 mA h g⁻¹ at 1 A g⁻¹.
• The hybrid supercapacitor demonstrated a maximum specific capacity of 158 mA h g⁻¹ at 1 A g⁻¹, with an energy density of 126.4 Wh kg⁻¹ and good cycle stability.

Conclusions:

• Intercalation of H2BDC effectively enhances the electrochemical performance of LDH electrodes by increasing interlayer spacing and surface area.
• The developed LDH hollow cages offer a promising electrode material for high-performance supercapacitors.
• The strategy of using organic ligand intercalation provides a viable route for optimizing LDH-based energy storage materials.