Cotton-Based Metal-Air Batteries without Catalysts as Low-Cost Micropower Devices

The cotton-based metal-air batteries without any catalyst are constructed. Especially, the continuous electrolyte flowing depends on the capillary force and the gravity from the height difference between the inlet and outlet. The performance of the cotton-based metal-air batteries under 2 mol L-1 NaOH or NaCl solutions is compared. The Al-air battery performance in the NaOH solution is better, while the Mg-air battery performance in the NaCl solution is the best. Considering the battery performance and cost, the alkaline cotton-based Al-air battery is investigated for the subsequent experiments. The Al-air battery performance is evaluated under the different cotton cloth makeups, NaOH concentrations, height differences between the inlet and outlet. The results show that under the conditions of the cotton makeup (20 (warp) x 60 (yarn)), 4 mol L-1 NaOH and 60 mm height difference, the battery performance is optimal, with the peak power density of 12.33 & PLUSMN; 0.38 mW cm-2 and limiting current density of 35.28 & PLUSMN; 0.73 mA cm-2. To apply the cotton-based Al-air battery, the two-battery stack connected in series powers 15 light-emitting diodes. The experiments demonstrate the cotton-based Al-air battery without catalysts owns low cost and high power output, which has great potential as a micropower device. The cotton-based metal-air batteries with the height differences from the inlet and outlet are constructed. The electrolyte flow depends on the capillary force with the gravity. The metal-air batteries performance under the alkaline or saline solutions is compared. Then, the alkaline Al-air batteries performance is evaluated under the different cotton cloth makeups, NaOH concentrations, and height differences.image & COPY; 2023 WILEY-VCH GmbH