Enhancing Stability and Capacity in Planar Zn‐Ion Micro‐Batteries via 3D Porous Ni Anode Integration

The development of planar on‐chip micro‐batteries with high‐capacity electrodes and environmentally friendly and stable architectures is critical for powering the next generation of miniaturized system‐on‐chip smart devices. However, realizing highly stable micro‐batteries remains a major challenge due to complex fabrication processes, electrode degradation during cycling, and the uncontrolled growth of dendrites in metal‐based anodes within the confined spaces between electrodes. To address these issues, this study presents an approach that incorporates a 3D porous nickel (Ni) scaffold at the metal anode, offering improved micro‐anode stability compared to conventional planar zinc and 3D porous zinc (Zn) scaffolds. Integrated into a planar configuration with a polyaniline (PANI) cathode and a zinc‐loaded 3D porous Ni scaffold anode, this design significantly enhances long‐term cycling stability, lowers charge transfer resistance, and increases charge storage capacity from 10 to 14 µAh cm −2 at 0.1 mA cm −2 compared to the same materials deposited on traditional planar gold microelectrodes. As a result, the Zn‐ion micro‐batteries achieve notable peak areal energy and power densities of 17.22 µWh cm −2 and 6.98 mW cm −2 , respectively. This work provides an effective strategy for improving the electrochemical performance and durability of planar micro‐batteries, marking a significant advancement toward the future of portable microelectronic devices.