A paper-based microfluidic aluminum–Air battery with intrinsic migration of electrolyte

The aluminum-air battery is one of the most promising candidates for next-generation miniaturized energy storage devices due to its high theoretical energy and capacity density. However, anodic self-corrosion and bulky liquid transportation systems have severely limited its practical energy density, hindering its usage for miniaturized applications. Here, we developed a microfluidic aluminum-air battery with zinc oxide (ZnO) as the inhibitor to overcome the abovementioned hurdles. The ZnO embedded alkaline electrolyte and microfluidic structure gain a maximum power density of 18.94 mW/cm2, an open circuit voltage of over 1.6 V, and a specific capacity of 2335.25 mAh/g (at 20 mA/cm2), while maintaining a low self-corrosion rate of 0.3043 mL/(cm2 min). In addition, the microfluidic design and ZnO embedment support the batteries to continuously work at 20 mA/cm2 for 120 min, 6.0 times the non-microfluidic ones and 1.18 times the microfluidic ones without ZnO. The performance of the battery can be improved by series connection or enlargement of the geometric active area. The design and method analogy proposed in this work can be readily migrated to the construction of miniaturized aluminum-air cell as reliable power sources.