Carbon/PTFE Air Cathode Performance from pH 0 to 14

摘要

The performance of an un-catalyzed air cathode for use in a Li-air battery was evaluated over the pH range from 0-14. This study was undertaken to determine if air cathodes constructed solely from carbon black and PTFE can function at a sufficient rate in sulfate based electrolytes to be useful in Li-Air batteries. Layered cathodes were constructed with a hydrophobic wet-proofing layer and an active hydrophilic layer that utilizes a high surface area carbon black. Electrolytes were formulated using H_2SO_4, Na_2SO_4, and NaOH in various combinations giving pH values ranging from 0-14. Electrolytes were also formulated using H_2SO_4, Li_2SO_4, and LiOH in combination and HCl, LiCl, and LiOH in combination giving electrolytes with pH values ranging from 0-14. The cathodes were discharged in a three electrode cell from 0V to -0.6V versus a Ag/AgCl reference electrode. The cathode performed well and met the requirement that a current density of at least 1-2 mA/cm~2 was maintained at -0.3V vs. Ag/AgCl.