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

The scaling effects make energy supply a fundamental challenge for achieving autonomy in insect-scale robotics. Inspired by the multifunctionality of biological tissue, dual-function structural-electrochemical integration based on a microfluidic aluminum-air battery (MFAAB) paves a promising path toward energy autonomy in insect-scale robotics. However, suboptimal mono-surface anode utilization and restricted microfluidic transport dynamics of conventional AABs accelerate passivation and byproduct accumulation, hindering output performance. Here, we proposed and developed a centimeter-size MFAAB with dual reaction surfaces for anode, and decompose byproduct accumulation via F^-. Owing to the novel structural configuration and electrolyte optimization, it achieves a high capacity of 2697.05 mAh/g_Al. The developed MFAABs demonstrate operational capacities of tens of milliwatts, successfully powering LEDs, DC motors, and electric toy car. We demonstrate the first successful integration of Al-air batteries with insect-scale robots through a structural-electrochemical co-design framework, harnessing energy weight proportion of 51.38%, achieving dual energy-storage and electromechanical actuation functions for self-sustaining operation. The integrated system simultaneously serves as a body-conforming structural power source while exhibiting 2.56-fold and 1.85-fold higher endurance than a commercial lithium-polymer (401015) and two series-connected alkaline button batteries (LR44), respectively.