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 cm-2 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.