Laser etching of on-chip ultra-high stability flexible micro MnO2//Zn batteries

Micro zinc batteries have great potential in fields such as smart clothing, wearable devices, and implantable medical devices, due to their high-energy density and biocompatibility, etc. However, the side reactions in Zn anode have limited their lifespan. Here we design a high stable fork-finger-shaped electrode using laser etching to obtain MnO2//Zn flexible miniature zinc ion batteries. And then, a carbon slurry is introduced to inhibit hydrogen evolution to suppress the detachment of the zinc anode. Compared with Au/PET interface, the PET/C interface had lower water retention and higher hydrogen evolution production barrier based on first-principles calculation. The interdigital electrode based on PET/C/Au had good stability. The micro MnO2–Zn flexible battery showed high specific capacity of 0.091 mAh/cm2 at 0.1 mA. After 5000 cycles at 0.5 mA, the capacity retention rate reached 83.6%. This study of interdigital electrode by laser etching brings an inspired universal pathway to fabricate a reversible Zn anode for micro-zinc storage systems.