Chemical bubbling of 3D porous elastomers toward stretchable high-energy-density Zn-Ag₂O microbattery

The development of stretchable microbatteries lags behind emerging wearable electronics and implantable devices. The main challenge is the mechanical mismatch between commonly used stretchable substrates and rigid conductive and active materials. Here, we proposed a 3D porous elastomer to significantly buffer this displacement of rigid components under strains. We develop a mild chemical bubbling strategy to prepare the highly porous elastomer, which proves superior for the fabrication of high-areal-energy–density and stretchable microbatteries. This design enables the excellent capacity retention of up to 123% under 100% strain for the fabricated Zn-Ag₂O microbatteries (ZAMBs), and also provides enormous surface areas to load abundant active materials to achieve a high areal energy density of 3.73 mWh/cm². Further vertical integrations with other functional modules realize real-time body monitoring on a smartphone, highlighting the critical role of stretchable microbatteries in wearable and implantable systems used under practical dynamic conditions. © 2025 Elsevier B.V.