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

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//I₂) MBs that exploit a synergistic dual-redox chemistry by introducing ZnI₂ into a Zn(CF₃SO₃)₂ gel electrolyte, enabling reversible I^-/I₃ ^- 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//I₂ 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^-/I₃ ^- 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.