Influence of aluminum doping on the properties of LiCoO2 and LiNi0.5Co0.5O2 oxides

Abstract

doi:10.1016/S0167-2738(02)00570-2 We have prepared LiCo1−yAlyO2 and LiNi0.5−yAlyCo0.5O2 (0≤y≤0.3) powder samples by a low temperature sol–gel method using succinic acid as chelating agent. We have studied the details of their crystallographic and local structure by X-ray diffraction (XRD) and FTIR spectroscopy, respectively; we have analyzed their chemical composition by ICP and obtained information about the morphology of the polycrystalline particles by SEM. Also, we have studied the electrochemical performance of the as-prepared materials in the Li LiNi0.5−yAlyCo0.5O2 cells cycled in the potential range 2.5–4.2 V finding that the overall capacity of the oxides has been reduced due to the metal substitution. For example, at 4.2 V cut-off, the charge capacity of the Li LiNi0.35Al0.15Co0.5O2 cell is ca. 115 mA h/g. However, more stable charge–discharge cycling performances have been obtained as compared to those displayed by the native oxides. Finally, we have characterized the kinetics of Li-diffusion by the galvanostatic intermittent titration technique and, according to our results, Al substitution provides an increase in the chemical diffusion coefficients of Li ions in the LiNi0.5−yAlyCo0.5O2 matrix

The Formation of Layered Double Hydroxide Phases in the Coprecipitation Syntheses of [Ni0.80Co0.15](1−x)/0.95Alx(OH)2(anionn−)x/n (x = 0–0.2, n = 1, 2)

“…Figure 6c,d shows that increased Al content broadens the dRM/dT peak in the second mass loss stage and delays the onset of the peak to higher temperatures as well. The latter trend has been noted in the past that Al can impart thermal stability to both precursor [14,17] and lithiated materials [8,9,43,45,46]. Figure 7 shows the TGA-MS results for the 0%, 10% and 20% Al samples.…”

Hubbard-corrected density functional perturbation theory with ultrasoft pseudopotentials

“…3 shows the phonon dispersion of LiCoO 2 and compares the results of DFPT and DFPT+U calculations with available Raman and infrared (IR) measurements at zone centre. The latter were performed on powder samples [91][92][93][94][95][96][97] (we are not aware of any INS experiment performed on single crystals of LiCoO 2 to sample its vibrational spectrum across the Brillouin zone) and at finite temperature, while our simulations are done at 0 K. Unlike in CoO and other TMOs [24], here GGA results are already in acceptable agreement with the experiments. Interestingly, the Hubbard correction leaves the acoustic and lower optical phonon branches (up to about 13 THz) almost unchanged, while it affects the upper part of the spectrum more substantially.…”

A routine for the determination of the microstructure of stacking-faulted nickel cobalt aluminium hydroxide precursors for lithium nickel cobalt aluminium oxide battery materials

“…Lithium-bearing transition metal oxides, LiMO 2 , such as LiCoO 2 (Ohzuku & Ueda, 1994;Winter et al, 1998), LiNiO 2 (Dahn, 1991), Li(Ni 1Àx Co x )O 2 (Delmas et al, 1999) and Li(Ni 1ÀxÀy Co x Al y )O 2 (NCA) (Castro-García, 2003;Chen et al, 2004), are important constituents in state-of-the-art lithium-ion batteries. The NCA materials are particularly favourable owing to their high specific capacity, which enables the production of high-energy Li-ion cells (Rozier & Tarascon, 2015;Radin et al, 2017;Kim et al, 2018).…”