Carbon Nanotube Based Robust and Flexible Solid-State Supercapacitor

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• All solid-state flexible electrochemical double-layer capacitors (EDLCs) are essential for powering wearable electronics and bendable micro/nanotechnology.
• Existing flexible EDLCs often face challenges with mechanical robustness and maintaining performance under stress.

Purpose of the Study:

• To develop robust, flexible, all solid-state EDLCs with enhanced energy storage capabilities.
• To investigate the performance and stability of these devices under various mechanical and thermal conditions.

Main Methods:

• Fabrication of EDLCs using aligned multiwalled carbon nanotubes (MWCNTs) grown on thin metal foils.
• Integration of MWCNTs within a poly(vinyl alcohol)/phosphoric acid (PVA/H3PO4) polymer gel electrolyte and separator.
• Testing device performance under static, flexed, and cyclic bending conditions, as well as across a temperature range.

Main Results:

• Achieved high areal specific capacitance (∼14.5 mF cm−2) and energy density (∼1 μW h cm−2), surpassing many existing flexible EDLCs.
• Demonstrated excellent mechanical robustness and flexibility, with no loss of capacity under flexed conditions and stability over ~2500 bending cycles.
• Devices maintained functionality across a temperature range of 20 to 70 °C.

Conclusions:

• The developed aligned MWCNT-based flexible EDLCs offer a promising solution for high-performance, durable energy storage in flexible electronic applications.
• Strategies like device stacking and thermal annealing can further enhance capacitive charge storage.
• These findings significantly advance the development of robust, stackable, and flexible all solid-state supercapacitors.