Performance Comparison of Paper‐ and Cotton‐Based Al‐Air Batteries without Catalysts for Low‐Cost Portable Micro Devices

Abstract Conventional Al‐air batteries are not suitable as portable power devices due to their complicated water management and bulky system. To resolve this issue, the fiber paper‐ and cotton cloth‐based Al‐air batteries were proposed, which exploited the capillary force from the paper (FP) and cotton cloth (CC) to deliver the solutions and eliminated the external pump. The physical features of the FP and CC were gained including the surface morphologies, surface elementary analysis, liquid absorption and flow rates. CC owned larger liquid absorption and faster flow rate due to its hierarchically woven‐spun fiber structure, compared to the randomly oriented fibers of the FP, although the surface of the CC demonstrated lower O/C ratio than that of the FP. So, the performance of the CC‐based Al‐air battery was largely higher than that of the FP‐based battery. The performance of the CC‐based Al‐air battery was optimal at 1.0 M NaOH electrolyte and the anode‐to‐cathode surface area ratio of 1 : 4, with the peak power density of 14.95±0.28 mW cm −2 , and the maximum current density of 36.61±0.54 mA cm −2 . To apply the CC‐based Al‐air battery, the two‐battery pack connected in series was assembled to drive a timer and light 9 LEDs.