High areal energy zinc-ion micro-batteries enabled by 3D printing

Rechargeable zinc-ion micro-batteries (ZIMBs) are promising candidates for powering various microelectronic devices, although they typically exhibit low areal energy of ∼0.1 mWh cm−². In this study, we reported the design and assembly of zinc micro-batteries through an ink extrusion-based printing approach. In the process, a three-axis printer was adopted, allowing for the fabrication of microelectrodes with large areal loading and diverse morphologies. Vanadium oxide anchored with carbon nanotubes was employed as the cathode material, zinc powder was used as the anode material, and a polyacrylamide gel containing ethylene glycol was selected as the electrolyte. The printed micro-batteries demonstrate an areal capacity of 0.51 mAh cm−² and an energy density of 0.37 mWh cm−² at a charge-discharge current of 0.2 mA, outperforming state-of-the-art zinc counterparts. This work provides a simple yet efficient solution to the development of high-energy micro-batteries.