Analysis of lithium peroxide content in lithium-air battery discharge via titration methodology

Lithium-air batteries have a high theoretical specific energy, comparable to gasoline and significantly higher than commercial lithium-ion batteries; however, there are several challenges to address [1]. This project aims to help in better understand the solid products produced from discharging the battery by quantitatively analyzing the lithium peroxide content in cathodes with various discharge capacities in several different solvents. The experiments were performed using titration methodology and UV-visible spectrophotometry. A quarter sized DMSO sample with a discharge capacity of 9.99 mAh had a theoretical lithium peroxide mass of 8.55 mg and an experimental lithium peroxide mass of 0.961 mg (88.8% percent difference). Two full sized cathodes (ELAT and T24081-10), which were discharged together in one battery, had a theoretical lithium peroxide mass of 38.5 mg and an experimental lithium peroxide mass of 10.8 mg (72.0% percent difference). Some potential explanations for these large percent differences are that there are other discharge products produced aside from lithium peroxide and that lithium peroxide content in cathodes after discharge is time dependent.