ATO cathodes from Li-O2 cells in different charge states are analyzed to quantify their Li2O2 and Li2O content. ATO cathodes are removed from the cells in an Ar-filled glove box, dried for 12 h at RT in a vacuum glass oven (Büchi, Switzerland), and then dispersed in defined amounts of ultra-pure deionized water (Millipore, ρ > 18 MΩ·cm). Due to the excess of water, Li2O2 is entirely converted to LiOH and H2O2 The formed H2O2 is then quantified as described in our previous work. Therefore, the dispersion is filtered to remove residual ATO. A defined amount of Titanium(IV) oxysulfate solution (1.9–2.1% for determination of hydrogen peroxide (H 15), according to DIN 38 409, part 15, DEV-18, Sigma-Aldrich) is added. Then the absorbance of the formed yellow [Ti(O2−)]2+ complex is measured by UV-vis spectroscopy (Lambda 35, Perkin Elmer, USA). Results are quantified using a reference absorbance curve derived from several defined amounts of commercial Li2O2, which were dissolved in H2O, converted to H2O2, and treated according to DIN 38 409. The Li2O2 content of commercial Li2O2 (technical grade, >90%, Sigma Aldrich, USA) was determined by thermogravimetric analysis to be 92.8%, as described previously. Error calculations include the standard error of slope and intercept of the calibration curve as well as the instrument's error of absorbance of 0.005. If you are looking for high quality, high purity, and cost-effective ATO, or if you require the latest price of ATO, please feel free to email contact mis-asia.