An investigation of local structures for 3d3, 3d5 and 3d7 ions doing in the layered LiCoO2 cathode materials

A Theoretical Study of Local Electronic–Magnetic Properties for LiCoMnO4 in the Charge and Discharge Process

“…Therefore, the more suitable model of D q and N based on two theoretical models (CF and CF + CT) in C 1 should be further selected. By comparing the calculated D q (in Table 1) with other similar Mn 4+ systems (TiO 2 : 2170 cm −1 [ 37 ] and Li[Co 0.98 Mn 0.02 ]O 2 : 2200 cm −1 [ 31 ] ), the values for two models are close and acceptable with minor errors. However, the covalence factor N from the CF model is much smaller than that in other Mn 4+ systems (Li[Co 0.98 Mn 0.02 ]O 2 [ 31 ] ) and less than 0.5.…”

“…By comparing the calculated D q (in Table 1) with other similar Mn 4+ systems (TiO 2 : 2170 cm −1 [ 37 ] and Li[Co 0.98 Mn 0.02 ]O 2 : 2200 cm −1 [ 31 ] ), the values for two models are close and acceptable with minor errors. However, the covalence factor N from the CF model is much smaller than that in other Mn 4+ systems (Li[Co 0.98 Mn 0.02 ]O 2 [ 31 ] ) and less than 0.5. According to the reported EPR investigations for various TMs other than Mn 4+ ion, [ 38,39 ] the possible range of N is 0.6 ≈ 0.95 and hence the N (≈0.45, 0.46, and 0.47) in C 1 would be inadvisable, representing the extremely strong covalency between the central Mn 4+ and ligand O 2− .…”

“…For example, compared with LiCoMnO 4 , [19] the similar composition of Li[Co 0.98 Mn 0.02 ]O 2 and Li[Co 0.98 Mg 0.01 Mn 0.01 ]O 2 shows evidently distorted [MnO 6 ] 8À octahedra with large anisotropies of g factors and zero-field splittings (D and E), which afford remarkably rhombically distorted 3d 3 center in CF model. [29][30][31] In addition, the g factors in LiCoMnO 4 (1.983-2.005 for C 1 , 2.090-2.14 for C 2 , and 2.014-2.21 for C 3 in Li-extracted and reinserted process) are much larger than the aforementioned two systems (with the average values of 1.986 and 1.982 in Li[Co 0.98 Mn 0.02 ]O 2 [29] and Li[Co 0.98 Mg 0.01 Mn 0.01 ] O 2 , [30] respectively). Therefore, the CT mechanism should be considered here, in view of the much larger g values for present systems.…”

High Near-Infrared Reflective Zn1–xAxWO4 Pigments with Various Hues Facilely Fabricated by Tuning Doped Transition Metal Ions (A = Co, Mn, and Fe)

“…With the doping of different transition metal ions, the lattice parameters and average grain size of these pigments have been refined and are given in Table 1; it can be observed that the lattice parameters (a, b, and c) have a slight decrease, resulting in a smaller cell volume, except Mn 2+ , and this may be ascribed to the induction of metal ions with a smaller radius (Co 2+ having 0.065 nm and Fe 3+ having 0.069 nm) than Zn 2+ (0.074 nm), 30,31 while Mn 2+ possesses a larger radius of 0.080 nm and leads to an increase in the lattice distortion and cell volume. 32 Figure 1b shows the crystal structure of the ZnWO 4 inorganic pigment, which owns the characteristic of the wolframite structure.…”

Recent Advances on Materials for Lithium-Ion Batteries

“…Improvements are relying on doping with different elements, surface coating with Li 3 NbO 4 and Co 3 O 4 layers [132], and also through electrolyte optimization [25]. Doping with transition metal ions in LiCoO 2 -based batteries has been shown to improve electrochemical properties due to the distorted local structure promoted by the impurity ions [133]. LiFePO 4 (LFP) is an active material of particular interest to be applied in electric vehicles.…”