Coordination Nanosheet-Based Electrochromic Supercapacitor with High Energy Storage, Switching Durability, and Long...

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Electrochromic (EC) supercapacitors combine energy storage with optical functions.
• Developing devices with high performance, long optical memory, and stability is crucial for advanced energy storage systems.

Purpose of the Study:

• To fabricate high-performance EC supercapacitors with long-term optical memory.
• To evaluate the electrochromic and supercapacitive properties of the fabricated devices.

Main Methods:

• Fabrication of EC supercapacitors using coordination nanosheets (CONASH) and nickel hexacyanoferrate (NiHCF).
• Characterization of electrochromic properties including optical contrast, switching times, coloration efficiency, and energy consumption.
• Assessment of supercapacitive performance including volumetric capacitance, energy density, power density, and cycling stability.
• Evaluation of self-discharge properties and long-term optical memory retention.

Main Results:

• The EC supercapacitor demonstrated a large optical contrast (57.4%) with short switching times (1.28/1.69 s).
• High coloration efficiency (619 cm2 C-1) and low energy consumption (3.6 mJ/cm2) were achieved, with over 50,000 EC switching cycles.
• The device exhibited excellent supercapacitive performance with high volumetric capacitance (248.1 F/cm3), energy density (29.37 mW h/cm3), and power density (7.5 W/cm3), stable over 40,000 cycles.
• Notably, the device showed significantly reduced self-discharge, retaining 33% optical contrast after 36 hours, indicating long optical memory.

Conclusions:

• The developed EC supercapacitor integrates superior electrochromic functionality with robust supercapacitive performance.
• The device's long optical memory and efficient energy storage capabilities offer a promising foundation for sustainable energy technology.
• This work highlights the potential of combining coordination nanosheets and redox-complementary materials for advanced energy storage applications.