A Reversible Zinc-Ion Microbattery from a Printed Gel-Electrolyte and a Carbon-Zinc Formulation.

Aqueous zinc ion batteries (ZIBs) are attracting increasing attention due to their low cost, earth abundance, and safety. So far, they have been regarded as a promising battery system for large scale grid applications, while here, we demonstrate prospects of their use to power portable devices. We report the fabrication of a rechargeable ZIB with interdigitated geometry capable of powering a commercial sensor for days. A full battery was assembled using aqueous and scalable formulations with a printed anode based on zinc powder and carbon black, a printed colloidal electrolyte, and a printed MnO cathode. The anode withstands more than 500 h of galvanostatic plating/stripping with a low overpotential of ∼32.2 mV, and the ZIB displays a capacity of ∼1.3 mAh/cm (∼129 mAh/g) and retains ∼66% of its capacity after 100 cycles. Finally, we show how this battery can power a Bluetooth proximity sensor, providing a voltage of 3.2 V for more than 3 days of continuous operation.