Penn State Engineers Develop Eel-Inspired Flexible Power Sources
Researchers at Penn State have engineered flexible and non-toxic power sources, drawing inspiration from electric eels. These innovative power sources are specifically intended for devices used in or near biological tissue, such as medical devices or soft robotics, where sufficient power is a critical requirement.
Inspired by Nature: The Research Approach
The team utilized a specialized fabrication method to layer multiple types of hydrogels, which are water-rich materials capable of conducting electricity. This intricate layering technique precisely mimics the ionic processes employed by electric eels to generate powerful electrical bursts.
Breakthrough Performance and Properties
This novel approach has resulted in power sources that boast higher power densities compared to other hydrogel-based designs. Furthermore, these new power sources are notably flexible, support-free, environmentally stable, and biologically compatible. The groundbreaking findings were officially published in the journal Advanced Science.
Overcoming Previous Challenges
Joseph Najem, an assistant professor of mechanical engineering and a corresponding author on the paper, addressed the limitations of prior research in this field.
"Prior research has examined electric fish biology as inspiration for soft power sources. However, previous eel-inspired devices exhibited limited power output and often required mechanical support."
To effectively address these persistent issues, the team meticulously modified the material chemistry. This modification allowed them to create thin hydrogels, thereby enabling increased power generation without the need for additional mechanical support. Najem highlighted that electric eel electrocytes are themselves ultra-thin biological cells capable of generating over 600 volts of electricity in short bursts, achieving remarkable high-power densities from very small volumes.
Innovative Material Selection and Fabrication
The power sources were constructed solely from hydrogel. This deliberate choice ensures they maintain non-toxic and flexible properties, even with their enhanced power output. Najem underscored the critical requirements for medical applications:
"For biomedical applications, batteries must be compatible, flexible, safe, and ideally rechargeable using available resources."
This guiding principle informed the meticulous development of these hydrogel-based power sources, specifically designed for seamless integration within biological environments.
The team utilized spin coating, a precise method for depositing ultra-thin material layers onto a rotating surface, to apply four distinct hydrogel mixtures. Each individual layer measured a mere 20 micrometers in thickness. Najem further explained that this exceptionally thin geometry is vital as it significantly reduces internal resistance, a key factor for achieving high power output, while simultaneously preserving both mechanical strength and flexibility.