Microscale Near-Neutral Zinc-Air Battery on Interdigitated Electrode Chips for High Current Operation.

Microbatteries are essential for powering compact electronic devices, where traditional batteries fall short due to their bulk and limited integration flexibility. Recent progress in advanced materials, 2D/3D microfabrication techniques, and printable nonlithium chemistries has enabled significant improvements in performance, safety, and scalability. Among emerging technologies, microscale zinc-air batteries (ZAMBs) offer promise, delivering high energy density while utilizing safe, earth-abundant materials and ambient oxygen as the cathodic reactant-making them a lightweight, sustainable, and cost-effective option for next-generation miniaturized electronics. In this work, underexplored compact ZAMBs specifically designed for microdevices is presented. These are fabricated using directly electrodeposited catalysts and microplotted Pt/C as bifunctional cathodes, with zinc deposited on a porous silver scaffold of interdigitated electrodes serving as the anode. The resulting devices achieve an areal capacity exceeding 20 µAh cm-2 at a high areal current of 2 mA cm-2, along with a volumetric capacity of 85 mAh cm-3 sustained over 100 cycles-outperforming previously reported most of microbatteries integrated on IDE platforms. Structural and electrochemical characterization confirmed the in situ formation of CoNi layered double hydroxide in the cathode, validating the feasibility of microscale bifunctional catalyst integration. Additionally, the use of a near-neutral electrolyte ensures robust performance under mild operating conditions, supporting seamless incorporation into compact energy storage systems.