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.