An Embodied Paper-Based Microfluidic Al-Air Battery for Enduring Untethered Insect-Scale Robots

Area of Science:

• Robotics
• Materials Science
• Electrochemistry

Background:

• Energy supply is a major hurdle for autonomous insect-scale robots.
• Conventional aluminum-air batteries (AABs) suffer from poor anode utilization and byproduct accumulation.
• Biological tissue inspires dual-function structural-electrochemical integration for energy autonomy.

Purpose of the Study:

• To develop an efficient microfluidic aluminum-air battery (MFAAB) for insect-scale robotics.
• To overcome limitations of conventional AABs, such as passivation and restricted transport dynamics.
• To achieve energy autonomy in insect-scale robots through structural-electrochemical co-design.

Main Methods:

• Designed and fabricated a centimeter-size MFAAB with dual reaction surfaces for the anode.
• Optimized the electrolyte to decompose byproduct accumulation using fluoride ions (F⁻).
• Integrated the MFAAB with insect-scale robots using a structural-electrochemical co-design framework.

Main Results:

• Achieved a high specific capacity of 2697.05 mAh/g_Al.
• Demonstrated operational power output in the tens of milliwatts, powering LEDs, motors, and a toy car.
• The integrated system achieved an energy weight proportion of 51.38% and showed 2.56x and 1.85x higher endurance than commercial lithium-polymer and alkaline batteries, respectively.

Conclusions:

• The developed MFAAB offers a promising solution for energy autonomy in insect-scale robotics.
• Dual-function structural-electrochemical integration enables self-sustaining operation and electromechanical actuation.
• This approach significantly enhances operational endurance compared to existing battery solutions.