Lightweight, compact, integrated, and miniaturized energy devices are under high pursuit for portable and wearable electronics. However, improving the energy density per area still remains a long-standing challenge. Herein, we report the design and fabrication of a solid-state zinc-air microbattery (ZAmB) by a facile 3D direct printing technique. The interdigital electrodes, gel electrolyte, and encapsulation frame are all printed with a customized design by optimzing the composition of the printing inks to obtain the best battery performance. Multiple layers of interdigital electrodes are sequentially printed with a fine overlap to achieve an ultrahigh thickness of 2.5 mm for a remarkably increased specific areal energy of up to 77.2 mWh cm-2. To meet the practical powering requirements for different output voltages and currents, battery modules consisting of individual ZAmBs connected in series or parallel or a combination of the two are printed with a facile integration to external loads. Powering of LEDs, digital watch, and a miniature rotary motor and even charging of a smartphone by the printed ZAmB modules are successfully demonstrated. The versatile 3D direct printing technique enables the fabricated ZAmBs with an adjustable form factor and integration capability with other electronics, paving the way for exploring new energy systems with diverse structures and extended functionalities.
Keywords: 3D printing; gel polymer electrolyte; interdigital electrode; microbattery; solid-state; zinc-air battery.