Cobalt segregation in the LiNi1−yCoyO2 solid solution: A preliminary 7Li NMR study

Rapidly convergent cluster expansion and application to lithium ion battery materials

“…These concentrations are compatible with the antisite disorder of a few percent, predicted in previous DFT calculations for pure LiNiO 2 . [13,47,48] This result also matches well to experimental data which shows a high density of Ni-antisite ions at low y [3,[14][15][16]. In the delithiated state, a fraction of cationic sites in Li-layer are vacant and mobile Ni 2+ in TMlayer will then tend to migrate to the vacant sites [49].…”

“…The highest-energy-density cathode materials are based on transition-metal (TM) oxides, such as LiMO 2 (M = Co, Ni, Mn) [1][2][3][4]. In particular, LiNiO 2 has received attention as a lower cost and toxicity alternative to the widely commercialized material LiCoO 2 [5][6][7][8].…”

Layered LT-LiNi1−yCoyO2 (0.3≤y≤0.7) cathodes for rechargeable lithium cells synthesized by co-precipitation method

“…Thus, the IR absorption bands of LiNi0.sCoo.502 microcrystalline powders are attributed as followed (the corresponding frequencies of other LiNil_yCoyO 2 compounds are summarized in Table 2 In the potential domain 3.0-4.0 V, the chargedischarge curves correspond to the voltage profiles characteristic of the LiNil_yCoyO 2 cathode materials associated with lithium occupation of octahedral sites, in agreement with previous works [7,9,13,35]. However, low-temperature synthesized LiNi l_yfoyO 2 cathode materials showed a lower potential for lithium deintercalation-intercalation than the materials prepared at high temperature (i.e., 800~ Similar behavior is also observed in the present investigation.…”

Magnetism and lithium diffusion in LixCoO2 by a muon-spin rotation and relaxation (μ+SR) technique

“…On the contrary, ν increases rapidly above 250 K for the x = 0.04 sample when T increases. This means that muon diffusion in the lattice begins above 250 K. Since ν is almost T independent for both Li[Li 0.04 Mn 1 [8], the difference in the ν(T) curves between Li 0.04 CoO 2 and Li 0.2 [Li 0.04 Mn 1.96 ]O 4 is probably due to the difference in "ion channel", i.e., two-dimensional channel in LiCoO 2 versus three-dimensional channel consisting of one-dimensional tunnels in LiMn 2 O 4 .…”

“…According to 7 Li NMR [1] and magnetic susceptibility (χ) measurements [2], the electronic configuration of Co 3+ in LiCoO 2 is in its low-spin state (t 6 2g ), suggesting the absence of magnetic transitions at low temperatures (T). Sugiyama et al [3], however, reported the appearance of localized moments below 65 K and long-range antiferromagnetic (AF) order below 30 K by muon-spin rotation and relaxation ( + SR) experiments, which is very sensitive to the local magnetic order.…”