Gravitational and Magnetic Bi‐Field Assisted One‐Step Quick Fabrication of Implantable Micro Zn‐Ion Hybrid Supercapacitor

Abstract The rapid advancement of implantable medical electronic devices has spurred substantial research into implantable energy storage systems. However, the presence of multiple film resistors in traditional sandwich structures impedes further enhancements in the electrochemical performance of supercapacitors and may result in contact failures between electrodes and separators or catastrophic short‐circuit failures during tissue deformation. This study introduces a novel approach for fabricating all‐in‐one Zn‐ion hybrid supercapacitors, which effectively mitigates performance degradation and safety concerns arising from interfacial issues. By leveraging the directed diffusion of magnetic carbon nanotubes and zinc particles within a cellulose acetate solution under the influence of magnetic and gravitational fields, coupled with rapid non‐solvent induced phase separation, an all‐in‐one Zn‐ion hybrid supercapacitor successfully fabricated. Thanks to the porous structure generated by polymer phase separation, the final prepared all‐in‐one device has a connected and fast ion transport channel between the cathode and anode. This innovative design demonstrates both superior electrochemical performance and high biocompatibility, achieving a maximum voltage output of 2 V and long‐term stability for up to 10,000 cycles. When connected in series, the integrated Zn‐ion hybrid supercapacitor can power an, showcasing its potential for next‐generation in vivo implants and micro‐robotic systems.