Comparing the ATR-FTIR spectrum of a discharged electrode to the reference spectra of pure lithium salts, it is clear that the electrode shows no absorption bands which could be coherently assigned to LiOH (3680 cm−1), Li2CO3 (1420 and 860 cm−1) or Li formate (1590, 1370 and 780 cm−1). However, it exhibits marginal absorption bands at 1600 and 1440 cm−1 indicating the presence of trace amounts of Li acetate (1570 and 1420 cm−1). The reference spectrum of a fresh ATO electrode shows that none of the characteristic bands of any Li salt is masked by absorption bands caused by ATO or the PTFE binder. To further demonstrate the sensitivity of the ATR-FTIR measurement, additional reference spectra of samples consisting of fresh cathode material (ATO + binder) intimately mixed with Li2CO3 or Li acetate are shown. The Li salt fractions in these samples equal the claimed fraction of Li2O in a discharged electrode. This would reference the hypothetic scenarios if all claimed Li2O on a discharged ATO electrode were Li2CO3 or Li acetate. The intensities of the resulting reference bands imply that the marginal absorption bands of the discharged electrode at 1600 and 1440 cm−1 cannot account for a substantial amount of Li acetate nor mask a significant amount of Li2CO3. It also has to be considered that only ∼1/3 of the present Li acetate traces are titrated (see Fig. S1 in the SI) so that ∼2/3 of all acetate species are part of the product fraction denoted as "other" rather than being part of the product fraction quantified by titration.
Consequently, Li2O, which does not possess any characteristic IR absorption bands in the accessible range, must be the only significant discharge product quantified by titration besides Li2O2. A fraction close to 42 ± 12% of the discharge capacity is therefore claimed to go into forming Li2O—an overview of the resulting product distribution, including all error margins. 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.
