Proton Insertion into Oxide Cathodes during Chemical Delithiation

A quantitative determination of proton contents in various chemically delithiated oxide cathodes has been carried out with prompt gamma-ray activation analysis (PGAA), and the results are complemented by mass spectrometric and thermogravimetric analysis data. While the delithiated layered , , and show a significant amount of proton in the lattice at deep lithium extraction, orthorhombic , spinel , and olivine do not encounter such proton insertion. Interestingly, spinel shows both proton insertion and oxygen loss at deep lithium extraction. The differences are attributed to the differences in the chemical instability of the various cathodes.