An aqueous Zn–MnO2 rechargeable microbattery

Microbatteries have recently attracted considerable attention due to their small-size and high energy and voltage output. However, the commonly used non-aqueous electrolytes are flammable and sensitive to moisture and oxygen contamination. In this work, an aqueous Zn–MnO2 rechargeable microbattery (micro-ZMB) with good electrochemical performance is developed. By simple laser carving and electrodeposition, in-plane interdigitated current collectors and active materials are obtained. The micro-ZMB exhibits a high specific capacity of 253.8 mA h g−1 (58.4 μA h cm−2) at a current density of 0.5 A g−1 (0.11 mA cm−2), approaching the level of conventional Zn-ion batteries. With proper packaging, a reversible specific capacity of 200 mA h g−1 is achieved even after 150 cycles. Compared with microbatteries reported previously, the as-prepared micro-ZMB exhibits longer cycling stability. Considering the safety of the aqueous electrolyte and stability of the Zn metal anode, the micro-ZMB holds great promise for use in miniaturized electronic devices.