Proton Insertion into Oxide Cathodes during Chemical Delithiation

Investigation of the possible incorporation of protons into oxide cathodes during chemical delithiation

“…The characterization data reveal that the delithiation of layered oxides involves an incorporation of protons into the lattice with aqueous acid, but not with an acetonitrile solution of the oxidizer NO 2 BF 4 proton insertion in both the aqueous and non-aqueous media. The results confirm that the loss of oxygen observed previously by us [11][12][13][14][15][16] at deep chemical lithium extraction of the layered LiMO 2 oxides with an acetonitrile solution of NO 2 BF 4 is not adversely influenced by any proton insertion into the lattice. We are in the process of characterizing further the delithiated phases by prompt-gamma ray activation analysis (PGAA), which can quantitatively determine the proton contents [34,35] and complement the FTIR data.…”

“…Although Ceder's group [10] has predicted based on theoretical calculations that the average valence charge on oxygen decreases with decreasing lithium content in Li 1Àx CoO 2 , not much experimental data are available with respect to the chemical instabilities. With an aim to experimentally assess the chemical instabilities, our group has been focusing on monitoring the variation of oxygen content with lithium content in bulk Li 1Àx MO 2 samples that were obtained by chemically extracting lithium from LiMO 2 with the oxidizer NO 2 BF 4 in an acetonitrile medium and are free from binder and carbon [11][12][13][14][15][16]. Our study has shown that the Li 1Àx MO 2Àd systems tend to lose oxygen for (1Àx)o0.…”

“…Our study has shown that the Li 1Àx MO 2Àd systems tend to lose oxygen for (1Àx)o0. 5 [11][12][13][14][15][16].…”

Spinel-type lithium cobalt oxide as a bifunctional electrocatalyst for the oxygen evolution and oxygen reduction reactions

“…Unlike in Co 3 O 4 , the Co 3 þ /4 þ oxidation/reduction in HT-LiCoO 2 is accompanied by lithium extraction/insertion. Also, HT-LiCoO 2 is known to insert protons into the lattice during chemical delithiation (with NO 2 BF 4 even in acetonitrile medium) for x40.5 in HTLi 1 À x CoO 2 and transform from the O3-layered structure to the P3-layered structure 32,33 . While the Li þ ions are in octahedral sites in the O3 structure, the Li þ /H þ ions are in prismatic sites in the P3 structure.…”

Effect of surface modifications on the layered solid solution cathodes (1−z) Li[Li1/3Mn2/3]O2−(z) Li[Mn0.5−yNi0.5−yCo2y]O2

“…If so, the oxidation state of Mn, Ni, and Co at the end of first discharge (reaction (4)) will be, respectively, Mn 3+ , Ni 2+ , and Co 2.74+ . On the other hand, it is possible that the oxidation of O 2− ions in the plateau region to release oxygen from the lattice may be accompanied by an oxidation of Co 3.6+ to Co 4+ as well, considering the highly covalent nature and a significant overlap of the Co 3+/4+ :t 2g band with the top of the O 2− :2p band [20,21]. If so, the composition at the end of first charge (reactions (2) and (3)) will be Li 0.06 [Li 0.07 M 0.8 ]O 1.665 □ 0.075 with all Mn 4+ , Ni 4+ , and Co 4+ .…”