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

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Supercapacitors require electrode materials with high stability, surface area, porosity, and efficient ion/electron transfer.
• Two-dimensional cluster-based Ni/Co-organic layers (Ni) offer high stability due to their Kagome lattice structure and pseudocapacitance behavior.

Purpose of the Study:

• To investigate the performance and stability of an optimized crystalline Ni/Co-organic layer (CMOL) material for supercapacitor applications.
• To evaluate the material in both liquid electrolyte and all-solid-state flexible asymmetric supercapacitor (ASCs) systems.

Main Methods:

• Synthesis and characterization of the crystalline CMOL material.
• Electrochemical testing in 1.0 M KOH and in assembled All-Solid-State Flexible ASCs.
• In situ X-ray diffraction (XRD) analysis during electrochemical cycling in a three-electrode system.

Main Results:

• The Ni material exhibited specific capacitance values of 1211 F g⁻¹ and 394 F g⁻¹ and an energy density of 54.67 Wh kg⁻¹ at 1 A g⁻¹.
• Excellent cycling stability was observed, with 92.4% capacitance retention after 5000 cycles (three-electrode) and 90% after 2000 cycles at 20 A g⁻¹ (ASCs).
• In situ XRD confirmed no structural degradation affecting cyclic stability during charging and discharging.

Conclusions:

• The optimized crystalline CMOL material demonstrates superior electrochemical performance and stability.
• The Ni material is a highly promising candidate for advanced supercapacitor applications, particularly in flexible devices.