Stepwise Artificial Yarn Muscles with Energy-Free Catch States Driven by Aluminum-Ion Insertion

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Current artificial muscles lack precise control and require continuous energy, limiting their practical applications.
• Weak material interactions and unstable structural changes hinder performance and energy efficiency.

Purpose of the Study:

• To develop artificial muscles with enhanced actuation precision and energy-free holding capabilities.
• To overcome limitations of existing artificial muscles using novel electrochemical mechanisms.

Main Methods:

• Utilized reversible faradaic insertion/extraction reactions between tetrachloroaluminate ions and collapsed carbon nanotubes.
• Engineered a yarn muscle capable of programmable stepwise actuation and energy-free states.

Main Results:

• Achieved nearly 100% maintenance of contractile strokes without power, even under loads 96,000 times the muscle weight.
• Demonstrated programmable control of actuation steps down to 1% with high precision.
• Generated high isometric stress (14.6 MPa), lockable and controllable without continuous energy input.
• Showcased energy storage capacity (102 mAh g⁻¹) enabling the muscle to act as a battery.

Conclusions:

• The developed artificial muscle offers unprecedented precision, energy efficiency, and load-bearing capacity.
• The novel mechanism enables energy-free actuation states and precise, programmable control.
• The dual functionality as an actuator and battery opens new avenues for advanced robotics and wearable devices.