Example XRD patterns for LiMn1.7Ni0.3O4 and LiMn1.7Fe0.3O4.
Table 1
Profile parameters obtained from the Rietveld refinement of the Ni doped series (CDS is Coherent Domain Size; estimated shape anisotropy is reported in curly brackets).
| Nominal composition | a [Å] | V [Å3] | CDS [nm] | Strain [%] | SG | Comment |
|---|---|---|---|---|---|---|
| LiMn1.9Ni0.1O4 | 8.222(1) | 555.9(2) | 91{1} | 0.25(5) | Fd3m | pure |
| LiMn1.8Ni0.2O4 | 8.203(2) | 552.0(2) | 36{7} | 0.25(2) | Fd3m | pure |
| LiMn1.7Ni0.3O4 | 8.190(1) | 549.4(2) | 58{32} | 0.40(6) | Fd3m | +2nd phase |
| LiMn1.6Ni0.4O4 | 8.190(1) | 549.3(2) | 107{78} | 0.52(5) | Fd3m | +2nd phase |
| LiMn1.5Ni0.5O4 | 8.172(2) | 545.8(2) | 43{1} | 0.12(2) | Fd3m | +2nd phase |
| LiMn1.5Ni0.5O4 | 8.167(1) | 544.7(2) | 51{10} | 0.0800(1) | Fd3m | [43] |
| LiMn2O4 | 8.207(1) | 552.8(1) | 80{7} | 0.3101(1) | Fd3m | [43] |
| Li1.12Mn1.88O4 | 8.2232(4) | 556.1 | Fd3m | [64] | ||
| Undoped | 8.2228(4) | Fd3m | [52] NPD | |||
| Ni(II) 0.07 | 8.2156(1) | Fd3m | [52] NPD | |||
| LiMn1.5Ni0.5O4 | 8.16594(3) | [53] XRD | ||||
| LiMn1.5Ni0.5O4 | 8.1690 | 36.9 | Fd3m/P4332 | [31] XRD |
Lattice parameter dependence (a) on nickel concentration for LiMn2–xNixO4 (the real concentrations were obtained by XPS and PGAA methods); (b) on iron concentration for LiMn2–xFexO4 (the real concentrations were obtained by XPS method).
Table 2
Profile parameters obtained from the Rietveld refinement of the Fe doped series (CDS is Coherent Domain Size; estimated shape anisotropy is reported in curly brackets).
| Nominal composition | a [Å] | V [Å3] | CDS [nm] | Strain [%] | SG | Comment |
|---|---|---|---|---|---|---|
| LiMn1.9Fe0.1O4 | 8.241(1) | 559.7(1) | 64{1} | 0.15(3) | Fd3m | pure |
| LiMn1.8Fe0.2O4 | 8.241(1) | 559.7(1) | 43{1} | 0.14(2) | Fd3m | pure |
| LiMn1.7Fe0.3O4 | 8.2454(8) | 560.54(9) | 50{1} | 0.15(2) | Fd3m | pure |
| LiMn1.6Fe0.4O4 | 8.2546(6) | 562.46(7) | 250{1} | 0.22(4) | Fd3m | pure |
| LiMn1.5Fe0.5O4 | 8.2547(6) | 562.47(7) | 113{1} | 0.24(4) | Fd3m | pure |
| LiMn2O4 | 8.207(1) | 552.8(1) | 80{7} | 0.3101(1) | Fd3m | [43] |
| Li1.12Mn1.88O4 | 8.2232(4) | 556.1 | Fd3m | [64] | ||
| Undoped | 8.2228(4) | Fd3m | [52] NPD | |||
| LiMn1.5Fe0.5O4 | 8.258(1) | 563.1(2) | 51{3} | 0.2444(1) | Fd3m | [43] |
Table 3
Chemical compositions and magnetic properties of the Ni series.
| XPS composition | Li/(Mn+Ni) 0.5: nominal | PGAA composition | Mn3+/Mn4+ | Theta [K] | µeff (µB) exp. | µeff (µB) calc. |
|---|---|---|---|---|---|---|
| Li1.16Mn1.82Ni0.13O3.89 | 0.60 | LiMn1.64Ni0.09 Oy | 0.61 | 16 | 6.1 | 5.9 Mn3+(HS), Mn4+, Ni2+ |
| Li1.36Mn1.93Ni0.2703.46 | 0.62 | LiMn1.44Ni0.16 Oy | 0.59 | 40 | 5.9 | 6.1 Mn3+(HS), Mn4+, Ni2+ |
| *Li1.16Mn1.65Ni0.2803.92 | 0.60 | LiMn1.54Ni0.28 Oy | 0.67 | 51 | 4.3 | 4.6 Mn3+(LS), Mn4+, Ni2+ |
| *Li1.01Mn1.73Ni0.41O3.82 | 0.47 | LiMn1.33Ni0.34 Oy | 0.64 | 110 | 3.7 | 5.0 Mn3+(LS), Mn4+, Ni2+ |
| *Li1.17Mn1.59Ni0.67O3.58 | 0.52 | LiMn1.29Ni0.44 Oy | 0.95 | 169 | 2.5 | 4.9 Mn3+(LS), Mn4+, Ni2+ |
Table 4
57Fe Mössbauer hyperfine parameters of LiMn1.5Fe0.5O4 where A is abundance, IS – isomer shift, QS – quadrupole splitting.
| Component | IS [mm/s] | QS [mm/s] | A [%] |
|---|---|---|---|
| D1 | 0.347±0.003 | 0.643±0.040 | 65.17 |
| D2 | 0.354±0.003 | 0.846±0.032 | 34.83 |
Table 5
Chemical compositions and magnetic properties of the Fe series.
| XPS composition | Li/(Mn+Fe) 0.5: nominal | Mn3+/Mn4+ | Theta [K] 1 T | µeff (µB)exp. | µeff (µB)calc. |
|---|---|---|---|---|---|
| Li1.18Mn1.78Fe0.12O3.92 | 0.62 | 1.54 | 128 | 4.88 | 4.88 0.75Mn3+(LS) + 0.25Mn3+(HS), Mn4+, Fe3+(LS) |
| Li1.17Mn1.80Fe0.17O3.87 | 0.59 | 1.17 | 100 | 4.86 | 4.85 0.82Mn3+(LS) + 0.18Mn3+(HS), Mn4+, Fe3+(LS) |
| Li1.37Mn1.70Fe0.21O3.70 | 0.71 | 1.09 | 89 | 5.65 | 5.62 0.4Mn3+(LS) + 0.6Mn3+(HS), Mn4+, Fe3+(HS) |
| Li1.23Mn1.82Fe0.27O3.67 | 0.59 | 1.33 | 288 | 5.20 | 5.21 0.8Mn3+(LS) + 0.2Mn3+(HS), Mn4+, 2/3Fe3+(LS) + 1/3Fe3+(HS) |
| Li0.91Mn1.66Fe0.31O4.12 | 0.46 | 1.76 | – | – | – |
Table 6
Structural parameters for the LiMn2–xNixO4 series.
| x | Anion parameter | Size K00 | Size K41 | Strain S400 | Strain S220 | ADP [Å2] | ||
|---|---|---|---|---|---|---|---|---|
| Li | Mn/Ni | O | ||||||
| 0.1 | 0.2697(3) | 1.10(2) | – | 0.62(2) | – | 3.3(7) | 3.87(7) | 3.7(1) |
| 0.2 | 0.2686(4) | 3.00(9) | 1.3(2) | 0.22(5) | 1.0(2) | 12(1) | 3.67(9) | 3.3(1) |
| 0.3 | 0.2587(3) | 2.56(7) | 2.6(2) | 0.36(6) | 3.3(2) | 3.0(fix) | 2.04(6) | 2.8(1) |
| 0.4 | 0.2594(3) | 1.60(7) | 1.8(1) | 0.98(7) | 4.7(2) | 3.0(fix) | 1.70(5) | 2.7(1) |
| 0.5 | 0.2710(3) | 2.34(4) | – | 0.15(2) | – | 9.0(1.0) | 4.4(1) | 3.3(2) |
Table 7
Structural parameters for the LiMn2–xFexO4 series.
| x | Anion parameter | Size K00 | Size K41 | Strain S400 | Strain S220 | ADP [Å2] | ||
|---|---|---|---|---|---|---|---|---|
| Li | Mn/Fe | O | ||||||
| 0.1 | 0.2704(3) | 1.55(2) | – | 0.23(1) | – | 6.3(9) | 4.68(8) | 5.5(2) |
| 0.2 | 0.2695(3) | 2.3(3) | – | 0.19(2) | – | 2.8(7) | 3.82(8) | 4.7(2) |
| 0.3 | 0.2697(3) | 2.00(3) | – | 0.25(2) | – | 3.7(8) | 4.2(1) | 5.1(1) |
| 0.4 | 0.2663(2) | 0.40(1) | – | 0.48(1) | – | 1.0(4) | 3.22(5) | 4.2(1) |
| 0.5 | 0.2646(2) | 0.88(2) | – | 0.60(1) | – | –0.1(3) | 2.66(5) | 3.8(1) |
SEM micrographs of the Ni series: (a) LiMn1.9Ni0.1O4, (b) LiMn1.8Ni0.2O4, (c) LiMn1.7Ni0.3O4, (d) LiMn1.6Ni0.4O4, (e) LiMn1.5Ni0.5O4, and Fe series: (f) LiMn1.9Fe0.1O4, (g) LiMn1.8Fe0.2O4, (h) LiMn1.7Fe0.3O4, (i) LiMn1.6Fe0.4O4, (j) LiMn1.5Fe0.5O4. Magnification 50000×, except (i) where it is 20000×.
57Fe Mössbauer hyperfine parameters of LiMn1.5Fe0.5O4. The fitted subspectra are presented on the spectrum.
XPS overview spectra of the samples with x = 0.5 for the Ni and Fe series.
XPS Mn3p and their deconvolution into synthetic lines of Mn3+, Mn4+ and Li1s for (a) the Ni series and (b) the Fe series.
XPS O1s of (a) the Ni and (b) Fe series. 1 marks oxygen in the compound, 2 to 5 enumerate additional lines.
XPS of the Ni2p (a) and Fe2p (b) lines.
The XPS spectrum of valence bands.
Magnetic susceptibility of (a) the Ni series and (b) the Fe series measured under 1 T.