3D Engineered Dual‐Redox Zinc‐Iodine Microbatteries for Intrinsically Safe on‐Chip Energy Storage

ABSTRACT The ongoing miniaturization of electronic technologies—from medical implants and microrobots to IoT and sensor networks—demands compact, intrinsically safe, and high‐energy‐density microbatteries (MBs). Yet, achieving on‐chip energy storage that simultaneously delivers high capacity, rapid kinetics, and scalability remains a formidable challenge. Here, we report advance zinc‐iodine (Zn//I ₂ ) MBs that exploit a synergistic dual‐redox chemistry by introducing ZnI ₂ into a Zn(CF ₃ SO ₃ ) ₂ gel electrolyte, enabling reversible I ⁻ /I ₃ ⁻ conversion in tandem with Zn ^{2 +} plating/stripping. Coupled with a polyaniline (PANI) micro‐cathode, zinc micro‐anode, and 3D porous Au interdigitated current collector, this architecture delivers over 26‐fold enhancement in charge storage relative to conventional Zn‐ion MBs using identical electrodes. The optimized Zn//I ₂ MBs achieve an improved areal capacity of 314 µAh cm ^{− 2} , energy density of 363 µWh cm ^{− 2} , and power density of 5385 µW cm ^{− 2} . Density functional theory (DFT) calculations and electrochemical analyses reveal strong I ⁻ /I ₃ ⁻ adsorption on PANI, confirming its superior redox hosting capability and hybrid charge storage behavior. This work establishes a new design paradigm for intrinsically safe, and CMOS‐compatible Zn‐based MBs, offering a transformative pathway toward on‐chip powered, fully integrated microsystems and next‐generation smart electronics.