Continuously powering intelligent microrobots through an electrochemical polymer skin membrane

Autonomous microrobots require electric power, sensing capability, and intelligence. However, at the microscale, traditional technologies struggle to simultaneously provide sufficient energy density and power while enabling intelligent environment recognition. This paper reports an open polymer engineering system enabling continuous microrobot operation without energy density limitations and active energy seeking through electrochemical environment recognition. The core innovation is a membrane design based on a crosslinked potassium polyacrylate membrane attached to the microrobot’s foot. This engineered skin membrane extracts chemical energy from contacting metal or silicon substrates and converts it into electricity via controlled reaction kinetics of an electrochemical process that utilizes atmospheric moisture and oxygen. Fabricated down to ∼1 mm2 area and 0.05 mm thickness, this open system is ideal for millimeter-to-centimeter scale microrobots. The skin membrane delivered a power density of 133 mW cm−2, an order of magnitude higher than microbatteries, and powered a microrobot for over 10,000 walking steps. Furthermore, the system demonstrates intelligent control of mass transport; internal ion migration within the membrane enables recognition of substrate material and roughness, facilitating active energy pursuit.