Skin-conformable printed supercapacitors and their performance in wear

Area of Science:

• Materials Science
• Electrical Engineering
• Biomedical Engineering

Background:

• Wearable sensors require compatible energy storage solutions for practical application.
• Different wearable formats (clothing integration vs. skin attachment) impose unique device requirements.
• Printed electronics offer a potential pathway for developing conformable and biocompatible devices.

Purpose of the Study:

• To evaluate the performance and durability of printed supercapacitors directly attached to the skin.
• To assess the mechanical and electrical reliability of skin-mounted supercapacitors under realistic conditions.
• To investigate the compatibility of these supercapacitors with skin movement and deformation.

Main Methods:

• Fabrication of printed supercapacitors using benign materials (water, carbon, sodium chloride).
• Attachment of devices to the forearm or chest for 24-hour durability testing.
• Electrical characterization, including capacitive function, equivalent series resistance, and leakage current.
• Digital Image Correlation (DIC) for full-field strain measurements to assess skin-device interaction.

Main Results:

• Supercapacitors demonstrated excellent mechanical durability and maintained secure attachment to the skin throughout the 24-hour test period.
• Reliable capacitive function was observed, with only minimal changes in equivalent series resistance and leakage current.
• Digital Image Correlation confirmed good mechanical compatibility, showing supercapacitors deform with the skin without hindering movement.

Conclusions:

• Printed supercapacitors utilizing safe, abundant materials are a viable energy storage solution for skin-attachable wearable electronics.
• These devices exhibit robust mechanical and electrical performance suitable for long-term skin-based applications.
• The supercapacitors' ability to conform to skin movement suggests high potential for comfortable and functional wearable systems.