Versatile Approach Combining Theoretical and ... - ACS Publications

Subscriber access provided by University of Sussex Library

Article

Versatile Approach Combining Theoretical and Experimental Aspects of Raman Spectroscopy to Investigate Battery Materials: The Case of LiNi Mn O Spinel 0.5

1.5

4

Lucien Boulet-Roblin, Claire Villevieille, Philippe Borel, Cecile Tessier, Petr Novák, and Mouna Ben Yahia J. Phys. Chem. C, Just Accepted Manuscript • DOI: 10.1021/acs.jpcc.6b04155 • Publication Date (Web): 01 Jul 2016 Downloaded from http://pubs.acs.org on July 5, 2016

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a free service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are accessible to all readers and citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

The Journal of Physical Chemistry C is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 20

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

The Journal of Physical Chemistry

Versatile Approach Combining Theoretical and Experimental Aspects of Raman Spectroscopy to Investigate Battery Materials: The Case of LiNi0.5Mn1.5O4 Spinel L. Boulet-Roblin,† Claire Villevieille,†* Philippe Borel,# Cécile Tessier,# Petr Novák,† and M. Ben Yahia‡* †

Paul Scherrer Institute, Electrochemistry Laboratory, CH-5232 Villigen PSI, Switzerland

#

SAFT, 111 Boulevard Alfred Daney, F-33074 Bordeaux, France

‡

Institut Charles Gerhardt, CTMM, CNRS 5253, Université Montpellier, Place Eugène Bataillon,

34095 Montpellier, Cedex 5, France.

ABSTRACT. We report a correlation between experimental and theoretical Raman spectra. Using density functional theory calculations, we resolve the last bottleneck in the understanding of Raman spectra by simulating and coupling the Raman vibrational modes to their calculated intensities of the promising 5-V LiNi0.5Mn1.5O4 spinel cathode. The origin of the simulated Raman intensities is elucidated thanks to a careful analysis of the electronic structure performed on the vibrating atoms in a solid compound. This novel approach leads to correctly assign the main vibration modes to Li-O bound motions which are indirectly linked to Mn or Ni (or both)

ACS Paragon Plus Environment

1


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 2 of 20

contrary to what was reported in the literature so far. This methodology will lead to a better understanding of the reaction mechanisms of active materials used for energy applications.

INTRODUCTION Renewable energy and “zero-emission” mobility are the next challenges through which our society can decrease its environmental pollution problems. Nowadays, Li-ion batteries are the most advanced storage devices able to meet these ambitious objectives. However, Li-ion batteries have recognized limitations, especially in terms of energy density, which is yet insufficient to provide a reasonable autonomous range for vehicular applications. LiNi0.5Mn1.5O4 spinel (called hereafter LNMO) is a promising cathode material due to its high operating voltage (~4.7 V vs. Li+/Li) and energy density (~690 Wh/kg), offering double the energy density available in today’s commercial systems. 1,2 Two LNMO polymorphs have been reported—ordered LNMO (P4332)3 and disordered LNMO (Fd-3m)4—and their structural stabilities strongly depend on their synthesis conditions. In the latter, Ni and Mn atoms are “randomly” distributed over the 16d Wyckoff sites, in contrast to the ordered material. Unfortunately, conventional X-ray diffraction cannot easily differentiate these arrangements,5 and thus, neutron diffraction and/or vibrational spectroscopies have been employed.3,6,7 Regrettably, the interpretation of the vibrational spectra, especially the Raman spectra, is not obvious, and quite often rigorous analyses are not reported, leading to speculative and possibly wrong Raman mode assignments, and thus, a lack of understanding of the associated LNMO mechanisms. Disordered LNMO is a typical case for which different approaches were used in the literature and conclusions were drawn based on only assumptions. As an example, the Ni−O and Mn−O vibrational modes are considered to be discernible, and their assignments have been made by comparing LiMn2O4 to LNMO.8,9 To date, no direct proof


2

Page 3 of 20

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


of the validity of such pre-cited concept has been given. Proposing a novel methodology and solving such a problem could afford a new dimension to Raman spectroscopy, enabling it to follow the oxidation states of transition metals. Usually, such information is obtained by X-ray absorption spectroscopy, which describes the bulk rather than the near-surface region (typically ca. 20 to ca. 300 nm for an electrode material) as with Raman techniques.10 Since the experimental interpretation of the Raman spectrum is quite often misleading, a novel approach that combines experimental and theoretical aspects would be crucial for the Raman spectroscopy community in circumventing ambiguous interpretations. Density functional theory (DFT) calculations have been heavily used in recent years to simulate the vibrational modes of Raman spectra; unfortunately, determining the relationship between the intensity of a peak associated with a vibrational mode is hardly feasible from a crystal simulation point of view. Therefore, attempts to assign spectra based only on the vibrational mode are often unreliable. Recently, the last bottleneck was overcome with the possibility of simulating the intensity of the vibrational modes with reasonable time and cost expenditures, and thus, gaining a deeper understanding of a materials’ properties.11–13 From an electrochemical point of view, the intensity of the Raman spectrum is a crucial parameter to follow during lithiation/delithiation (sodiation/desodiation), since it gives indications not only about the reaction mechanisms and possible intermediate species but also the oxidation state of the transition metals, the different phase proportions, and, last but not least, the evolution of the conductivity of the samples during cycling. Knowing the vibrational modes and their intensities will give access to new perspectives for Raman spectroscopy since it is a near-surface characterization technique, complementary to other common laboratory techniques such as X-ray diffraction and infrared spectroscopy.


3


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 4 of 20

Thus, using the Coupled Perturbed KS method implemented in the CRYSTAL14 code, we were able to reproduce for the first time the Raman spectra of the LNMO materials by means of indexing the vibrational modes relative to their intensities, leading to a breakthrough in the understanding of the materials and of Li-ion material characterization.11,12,14–16 EXPERIMENTAL SECTION Disordered LNMO (d-LNMO) was provided by SAFT (France), whereas ordered LNMO (oLNMO) was obtained via calcination of the d-LNMO at 700 °C for 40 h in air. The LNMO samples were characterized by neutron powder diffraction (PSI, SINQ, HRPT). The Raman spectra of d-LNMO and o-LNMO were acquired using a Labram HR800 Raman microscope (Horiba-Jobin Yvon), equipped with a He-Ne laser (632.8 nm) and having a lateral resolution of ~2 µm (50 x objective). For the computations, geometry optimisations and vibrational properties within the harmonic approximation were performed via DFT simulations17,18 combined with the B3LYP functional19 and a spin-polarised all-electrons description. This association was previously tested with convincing results.20–23 To correctly reproduce the variation of the polarizability and thus, the Raman tensor, a fine sampling of the Brillouin zone (30 x 30 x 30 points) was used as well as large Gaussian-type basis sets: 6-1124, 86-411(d41)25, 86-411(d41)25, and 8-41125 for Li, Mn, Ni, and O, respectively. RESULTS AND DISCUSSION Figure 1 presents the neutron diffraction patterns of both LNMO materials (disordered and ordered). More details about the refinement can be found in the supplementary data. For dLNMO, we identified LixNi1-xO as an impurity (rock salt-type).26 This leads to the formation of small amounts (ca. 5 %) of electrochemically active Mn3+. The materials are different not only in


4

Page 5 of 20

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


terms of structure (Figure 2), but also in electrochemical performance, where d-LNMO behaves better.27 However, it is more challenging to simulate its Raman spectrum since the atomic positions of Ni and Mn are statistically distributed in the same sites.

Figure 1. Neutron diffraction patterns of o-LNMO and d-LNMO. For Raman spectrum simulation, we need to provide an accurate description of the d-LNMO structure, and a super-cell with various Ni distributions is required. However, such computations are not easy and consume significant computing resources. Moreover, the vibrational properties are proportional to the number of atoms, and the aleatory distribution of Ni/Mn leads to a quasiinfinite number of combinations. Thus, we considered several unit cells in which Ni is positioned in different atomic sites to emulate the Ni–Ni interactions, and tested their stability. Among the five possibilities—i.e. chain, tetrahedral, trimer, dimer, or without any Ni–Ni bond—the most stable structure, “cLNMO”, is found when there is no Ni–Ni bond in the R-3m space group (supplementary data, Table S4). As can be seen from the structural model in Figure 2, the nickel distribution is slightly


5


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 6 of 20

different than that in o-LNMO. In the latter, the Ni atoms occupy octahedral sites with D3 symmetry, whereas in our model, they exhibit D3d symmetry. Regarding the oxygens, we can distinguish two sites in our model, O1 and O2 (Figure 2), having tetrahedral environments. The first coordination sphere of O1 contains one Li and three Mn atoms, whereas O2 is surrounded by one Li, one Ni, and two Mn atoms. The Ni atoms adopt a regular first coordination sphere with six Ni–O bonds (1.895 Å interatomic distance), while in the case of Mn atoms, two Mn–O bond distances are found (1.925 and 1.943 Å), suggesting slight Jahn-Teller distortion. This result confirms the presence of Mn3+ inside the model. The structural differences between oLNMO and c-LNMO were verified by comparing their neutron diffraction patterns (see supplementary data, Figure S3). Our most stable model is in agreement with the reported “uniformly disordered” model of Lee and coworkers.28

Figure 2. Structural representations of Li atom neighbours for d-LNMO (Fd-3m), o-LNMO (P4332), and c-LNMO (R-3m) as structural models for Raman calculations. The vibrational mode calculations were then conducted on a primitive cell (two Li, three Mn, one Ni, and eight O) leading to a total of 36 vibrational modes, among them 5Eg and 4A1g Raman active modes. For d-LNMO, A1g, Eg, and 3T2g modes were calculated. The lowering of the local symmetry from Oh (Fd-3m) to D3d (R-3m) brings two additional modes and leads to the degeneration of the T2g modes into A1g and Eg modes, whereas the A1g and Eg of d-LNMO are


6

Page 7 of 20

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


maintained for the R-3m structure. It is important to note that the bond vibrations are only due to oxygen and/or lithium displacement, while the transition metals are motionless. Even being fixed, Ni and Mn are bonded to oxygens, and therefore, their electron clouds are influenced by the first and second shell orders of their neighbours’ motions, respectively, oxygen and lithium. Finally, LO-TO splitting cannot be the origin of the Raman signals for this calculation phase due to symmetry reasons. Figure 3 presents a comparison of the simulated and experimental Raman spectra for the LNMO family. For clarity, we normalized the spectra with respect to the most intense peak. The calculated intensities were simulated with similar laser wavelengths and temperatures as the experimental measurements. The calculated Raman intensities were obtained from the contributions of all possible orientations of the crystal. Therefore, three rotational invariants with their integrals of the Raman tensors were considered, and produced two polarized components to the light source, i.e. parallel and perpendicular.29 The sum of these two intensity contributions results in the total Raman spectrum (green curve, Figure 3). As can be seen, the d-LNMO and cLNMO Raman spectra are fairly similar. This matching is even more pronounced with the spectra using parallel calculated intensities, indicating a preferential orientation of the grains of the d-LNMO while collecting the Raman spectrum.


7


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 8 of 20

Figure 3. Experimental and calculated Raman spectra of LNMO family Indeed, several groups have reported Raman spectra with the most intense peak at 509 cm−1 for LNMO synthesized at 800°C,2,30–32 whereas other groups (including ours) noted the peak at 642 cm−1 as the most intense.1,9,33,34 It appears that these differences are related to neither the laser wavelength of the Raman spectrometer nor the synthesis temperature, since there is no logical trend in the peak/intensity evolution. To exclude the impact of the synthesis temperature on the particle shape, we synthesized d-LNMO at various temperatures (730 to 900 °C) and evaluated the impact on the Raman spectra (results are displayed in Figure S4) but no differences were observed for the intensity ratio of 509/642 cm−1 peaks. Thus, the only possible explanation is the crystal orientation of the grains probed by Raman spectroscopy. Usually, the (100) or (111) planes are found at the surface.35,36 Since the Raman laser has a low penetration depth (ca. 160 nm for c-LNMO, considering our calculated refractive index of ca. 1.27), it is then possible to not probe an average of all crystal planes. The assignments of the calculated c-LNMO Raman peaks and their modes are reported in Table 1. Since the main debate is related to the most intense peaks, the next part of our discussion will focus on those.


8

Page 9 of 20

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Table 1. Assignments of the calculated vibrational Raman modes. (δ) and (ν) correspond to bending and stretching modes, respectively. S and M annotations correspond to strong and medium contributions to the peak intensity, respectively. Frequency [cm-1] 642

// (Total) Intensity [a.u.] 650 (851)

Symmetry

Assignments

A1g

Li–O1 (ν) S Li–O2 (ν) M Mn–O1–Li (δ) S Ni–O2–Li (δ) M

599

67 (82)

A1g

Li–O1 (ν) S O2–Mn–O2 (δ) S

570

4 (7)

Eg

Mn–O1(ν) S Mn–O1–Mn S (δ) Li–O1–Mn (δ) S O2–Li–O2 (δ) S

534

144 (178)

A1g

Li–O2–Ni (δ) S O2–Li–O1(δ) S

509

572 (1000)

Eg

O2–Li(ν) S Ni–O2–Li (δ) M O2–Li–O1 (δ) M

441

358 (624)

Eg

Li–O2(ν) S O2–Li–O2 (δ) S

410

19 (34)

Eg

Mn–O1 (ν) M Mn–O1–Mn(δ) M

405

141 (179)

A1g

Ni–O2–Li (δ) S O2–Li–O1 (δ) S

375

46 (80)

Eg

O1–Li–O2(δ) S Li–O1–Mn (δ) S


9


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 10 of 20

The A1g peak at 642 cm−1 is mainly attributed to the stretching of the oxygens (O1 and O2) in the Li–O bonds, as is shown by the vibration vector amplitude (Figure 4a). This mode corresponds to the symmetric “breathing” of the MO6 octahedra, as described in the literature.30,37 To understand the origin of its high intensity (i.e. large change in polarizability which is proportional to the electronic density deformation), we calculated the interatomic overlap populations at equilibrium and at the maximum vibrational amplitude displacement. As reported in the Table 2, only the overlap population of the Li–O1 bond varies strongly with the A1g vibration, whereas the electronic densities of interatomic bonds including Mn and Ni do not evolve significantly. Indeed, a higher negative overlap population means that the Li–O bond becomes stronger, resulting in an increase in the electron density on oxygen, which would then be easily deformable when approached by Li. Thus, and unlike all the literature describing the Raman spinel assignment, the origin of the high intensity of the peak at 642 cm−1 is not related to the Mn–O bond vibration, but to the shortening of the Li–O1 distance (which induces a strong increase in polarizability with the lithium motion). Thus, only Mn atoms contribute indirectly to the vibration since the involved oxygen O1 is not connected to any Ni atoms. Finally, the broadening of the peak at 642 cm−1 (compared to the o-LNMO) is indirectly due to the presence of Mn in two oxidation states (+3 and +4) in c-LNMO and d-LNMO, which affects the charge density of the Li–O1 bond. Table 2. Interatomic overlap population of c-LNMO metal-oxygen bonds at equilibrium position (Eq.) and during vibration normal modes, respectively A1g (642 cm-1) and Eg (509 cm-1 and 441 cm-1). Written numbers in bold show the great variations.

Interatomic

Overlap populations


10

Page 11 of 20

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


bonds Eq.

A1g

Eg(1)

Eg(2)

Eg(1)

Eg(2)

(642 cm-1)

(509 cm-1)

(509 cm-1)

(441 cm-1)

(441 cm-1)

Mn-O1

0.054

0,046

0.053

0.053

0.046

0.048

Mn-O2

0.047

0.062

0.047

0.053

0.051

0.055

Ni-O2

0.039

0.017

0.037

0.038

0.026

0.025

Li-O1

-0,032

-0.345

-0.023

-0.024

-0.023

-0.027

Li-O2

-0,023

-0.033

-0.200

-0.148

-0.010

-0.013

The second most intense peak at 509 cm−1 has Eg symmetry. It is mainly assigned to the stretching of Li–O2 (see Figure 4b). Contrary to the previous A1g mode, both Li and O atoms are involved in the motion. During vibration, the interatomic Li–O2 overlap population is the most affected (Table 2), while the electronic densities of bonds involving Ni and Mn do not change significantly. Thus, the modification of the density around the oxygen O2 is at the origin of the high intensity. If one considers Mn as non-electrochemically active, since its oxidation state mainly stays constant at Mn4+, the oxidation state of Ni could then be followed via this vibrational mode with its impact on the electronic density of O2. The juxtaposition of the theoretical and experimental spectra shows a slight shift of the peaks to higher wavenumbers. A comparison of the simulated M–O bond distances to the neutron diffraction results shows good agreement for the Mn–O bond, whereas the Ni–O bond seems shorter than expected. The shortening of this interatomic distance may induce a slight blueshift in the Raman spectrum when Ni and O2 are participating in the vibration. This phenomenon could be attributed to the antiferromagnetic order considered in our calculations model.


11


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 12 of 20

Figure 4. Structural representation of c-LNMO during vibrational motion for a) 642 cm−1 A1g and b) 509 cm−1 Eg modes The oxidation states of the transition metals only indirectly influence the two main vibrational modes, i.e. Mn with A1g and Ni with Eg. These findings refute most of the papers published on LNMO and their assignments of the Raman modes. Moreover, these results highlight the lack of knowledge and understanding of Raman spectroscopy in the literature,8,9 since, in contrast to what has been reported, it is mainly the Li–O bond at the origin of these peaks. It is worth noting that the calculated peak at 441 cm−1 does not appear to exist in the experimental Raman spectrum of d-LNMO (Figure 3). However, after careful inspection of the o-LNMO Raman spectrum, we observe a peak with similar intensity and shape at ca. 400 cm−1. According to the DFT calculations, this peak is ascribable to the bending of O2–Li–O2 and the stretching of the O2–Li bond. Fixing the Ni position in c-LNMO induces changes in the second and third neighbouring shells, compared to d-LNMO, and thus, some vibrational modes can be found to be “extinguished” or reduced in terms of intensity. In the present case, the Raman intensity is not exclusively dominated by the change in polarizability of the oxygen via Li


12

Page 13 of 20

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


interaction, but also arises from the covalent nature of the M–O bonds and, in particular, the Ni– O bond (Table 2). A slight modification of the Ni–O interatomic distance (i.e. the shortening in c-LNMO) heavily impacts the Ni–O electron cloud density during vibration, and thus, induces a large change in intensity. Finally, we can assume that this peak is probably integrated into the broad band recorded at ca. 400 cm−1 in the d-LNMO Raman spectrum. So far, we have been able to reproduce almost the entire spectrum, and only a small peak located at 670 cm−1 (marked with an asterisk in Figure 3) cannot be reproduced by the simulation. One possible explanation is that the calculations were performed for a primitive cell four times smaller than the “real” d-LNMO cell, and therefore, the vibrational modes between two primitive cells are not well reproduced in the present case.

CONCLUSION We were able to reproduce and assign the vibrational modes for the LNMO family and to correlate them with their intensities using interatomic overlap population calculations. We showed that the most intense band at 642 cm−1, ascribable to the A1g mode, is attributed to the oxygen stretching of the Li–O1 bond. This oxygen, being only bonded to Mn, allows us to follow the activity of the Mn atoms (changes in oxidation state). The second-most intense peak at 509 cm−1, attributed to the Eg vibrational mode, is mainly due to the stretching of Li–O2. In this case, Ni and Mn are bonded to the vibrating oxygen. Therefore, and contrary to prior reports, we can only indirectly differentiate the transition metals within the A1g vibrational mode at 642 cm−1 and the Eg mode at 509 cm−1 (when considering Mn as non-electroactive). We thus demonstrate that the simulation of Raman intensities using DFT methods provides a versatile and suitable methodology for a better understanding of oxidation states and electrochemical processes.


13


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 14 of 20

ASSOCIATED CONTENT Supporting Information. Neutron diffraction patterns of disordered/ordered/calculated LiNi0.5Mn1.5O4, video animation of vibrational modes, Raman spectra of LNMO after different heat treatments, relative stability of different calculated LNMO and interatomic overlap populations of c-LNMO. This material is available free of charge via the Internet at http://pubs.acs.org.

AUTHOR INFORMATION Corresponding Author Dr. Mouna Ben Yahia Institut Charles Gerhardt Montpellier, UMR 5253 CNRS-UM-ENSCM, Université de Montpellier, Place Eugène Bataillon - Bâtiment 15 – RDC, 34095 Montpellier cedex 5 - France E-mail: [email protected] Phone: 00 33 (0)4 67 14 46 11 Dr. Claire Villevieille Paul Scherrer Institut, Laboratory of Electrochemistry, OVGA/123, CH-5232 Villigen PSI, Switzerland Email: [email protected] Phone: 00 41 (0)56 310 24 10


14

Page 15 of 20

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Notes A part of this work (neutron diffraction) is based on experiments performed at the Swiss spallation neutron source SINQ, Paul Scherrer Institute, Villigen, Switzerland. The authors declare no competing financial interest. ACKNOWLEDGMENTS Dr. Denis Sheptyakov is greatly acknowledged for fruitful discussions and help with the neutron diffraction refinements. The authors would like to thank SAFT for financial support. Furthermore, we would like to thank CINES for computational resources (project n° cmm6691) and Prof. Dr. Michel Rerat for software assistance. REFERENCES (1)

Kunduraci, M.; Amatucci, G. G. Synthesis and Characterization of Nanostructured 4.7 V LixMn1.5Ni0.5O4 Spinels for High-Power Lithium-Ion Batteries. J. Electrochem. Soc. 2006, 153, A1345–A1352.

(2)

Liu, D.; Zhu, W.; Trottier, J.; Gagnon, C.; Barray, F.; Guerfi, A.; Mauger, A.; Groult, H.; Julien, C. M.; Goodenough, J. B.; et al. Spinel Materials for High-Voltage Cathodes in LiIon Batteries. RSC Adv. 2014, 4, 154–167.

(3)

Ariyoshi, K.; Iwakoshi, Y.; Nakayama, N.; Ohzuku, T. Topotactic Two-Phase Reactions of LiNi1/2Mn3/2O4 (P4332) in Nonaqueous Lithium Cells. J. Electrochem. Soc. 2004, 151, A296–A303.

(4)

Kunduraci, M.; Kunduraci, M.; Al-Sharab, J.; Al-Sharab, J.; Amatucci, G.; Amatucci, G. High-Power Nanostructured LiMn2-xNixO4 High-Voltage Lithium-Ion Battery Electrode Materials: Chem. Mater 2006, 18, 3585–3592.


15


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

(5)

Page 16 of 20

Bhaskar, A.; Bramnik, N. N.; Senyshyn, A.; Fuess, H.; Ehrenberg, H. Synthesis, Characterization, and Comparison of Electrochemical Properties of LiM0.5Mn1.5O4 (M=Fe, Co, Ni) at Different Temperatures. J. Electrochem. Soc. 2010, 157, A689–A695.

(6)

Feng, J.; Huang, Z.; Guo, C.; Chernova, N. A.; Upreti, S.; Whittingham, M. S. An Organic Coprecipitation Route to Synthesize High Voltage LiNi0.5Mn1.5O4. ACS Appl. Mater. Interfaces 2013, 5, 10227–10232.

(7)

Shin, D. W.; Bridges, C. A.; Huq, A.; Paranthaman, M. P.; Manthiram, A. Role of Cation Ordering and Surface Segregation in High-Voltage Spinel LiMn1.5Ni0.5-xMxO4 (M = Cr, Fe, and Ga) Cathodes for Lithium-Ion Batteries. Chem. Mater. 2012, 24, 3720–3731.

(8)

Dokko, K.; Mohamedi, M.; Anzue, N.; Itoh, T.; Uchida, I. In Situ Raman Spectroscopic Studies of LiNixMn2-xO4 Thin Film Cathode Materials for Lithium Ion Secondary Batteries. J. Mater. Chem. 2002, 12, 3688–3693.

(9)

Park, D. H.; Lim, S. T.; Hwang, S.-J.; Choy, J.-H.; Choi, J. H.; Choo, J. Influence of Nickel Content on the Chemical Bonding Character of LiMn2−xNixO4 Spinel Oxides. J. Power Sources 2006, 159, 1346–1352.

(10)

Baddour-hadjean, R.; Pereira-Ramos, J.-P. Raman Microspectrometry Applied to the Study of Electrode Materials for Lithium Batteries. Chem. Rev. 2010, 110, 1278–1319.

(11)

Maschio, L.; Kirtman, B.; Rérat, M.; Orlando, R.; Dovesi, R. Ab Initio Analytical Raman Intensities for Periodic Systems through a Coupled Perturbed Hartree-Fock/Kohn-Sham Method in an Atomic Orbital Basis. I. Theory. J. Chem. Phys. 2013, 139, 164101.

(12)

Maschio, L.; Kirtman, B.; Rérat, M.; Orlando, R.; Dovesi, R. Ab Initio Analytical Raman Intensities for Periodic Systems through a Coupled Perturbed Hartree-Fock/Kohn-Sham Method in an Atomic Orbital Basis. II. Validation and Comparison with Experiments. J.


16

Page 17 of 20

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Chem. Phys. 2013, 139, 164102. (13)

Miwa, K. Prediction of Raman Spectra with Ultrasoft Pseudopotentials. Phys. Rev. B 2011, 84, 094304.

(14)

R. Dovesi, V. R. Saunders, C. Roetti, R. Orlando, C. M. Zicovich-Wilson, F. Pascale, B. Civalleri, K. Doll, N. M. Harrison, I. J. Bush, P. D’Arco, M. Llunell, M. C. and Y. N. CRYSTAL14 User’s Manual. University of Torino, Torino, 2014.

(15)

Dovesi, R.; Orlando, R.; Erba, A.; Zicovich-Wilson, C. M.; Civalleri, B.; Casassa, S.; Maschio, L.; Ferrabone, M.; De La Pierre, M.; D’Arco, P.; et al. CRYSTAL14 : A Program for Theab Initio Investigation of Crystalline Solids. Int. J. Quantum Chem. 2014, 114, 1287–1317.

(16)

Ferrero, M.; Rérat, M.; Kirtman, B.; Dovesi, R. Calculation of First and Second Static Hyperpolarizabilities of One- to Three-Dimensional Periodic Compounds. Implementation in the CRYSTAL Code. J. Chem. Phys. 2008, 129, 244110.

(17)

Hohenberg, P.; Kohn, W. The Inhomogeneous Electron Gas. Phys. Rev. 1964, 136, B864– B871.

(18)

Kohn, W.; Sham, L. J. Self-Consistent Equations INcluding Exchange and Correlation Effects*. Phys. Rev. B 1965, 140, A1133–A1138.

(19)

Becke, A. D. Density-Functional thermochemistry.III. The Role of Exact Exchange. J. Chem. Phys. 1993, 98, 5648.

(20)

Raffaella, D.; Bartolomeo, C.; Matteo, F.; Roberto, D. On the Performance of Eleven DFT Functionals in the Description of the Vibrational Properties of Aluminosilicates. Int. J. Quantum Chem. 2010, 110, 406–415.

(21)

Ben Yahia, M.; Lemoigno, F.; Beuvier, T.; Filhol, J.-S.; Richard-Plouet, M.; Brohan, L.;


17


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 18 of 20

Doublet, M.-L. Updated References for the Structural, Electronic, and Vibrational Properties of TiO2(B) Bulk Using First-Principles Density Functional Theory Calculations. J. Chem. Phys. 2009, 130, 204501. (22)

Ferrari, a. M.; Valenzano, L.; Meyer, a.; Orlando, R.; Dovesi, R. Quantum-Mechanical Ab Initio Simulation of the Raman and IR Spectra of Fe3Al2Si3O12 Almandine. J. Phys. Chem. A 2009, 113, 11289–11294.

(23)

Civalleri, B.; Napoli, F.; Noel, Y.; Roetti, C.; Dovesi, R. Ab-Initio Prediction of Materials Properties with CRYSTAL: MOF-5 as a Case Study. CrystEngComm 2006, 8, 364–371.

(24)

Ojamäe, L.; Hermansson, K.; Pisani, C.; Causà, M.; Roetti, C. Structural, Vibrational and Electronic Properties of a Crystalline Hydrate from Ab Initio Periodic Hartree–Fock Calculations. Acta Crystallogr. Sect. B Struct. Sci. 1994, 50, 268–279.

(25)

Towler, M. D.; Allan, N. L.; Harrison, N. M.; Saunders, V. R.; MacKrodt, W. C.; Aprà, E. Ab Initio Study of MnO and NiO. Phys. Rev. B 1994, 50, 5041–5054.

(26)

Liu, G. Q.; Wen, L.; Wang, X.; Ma, B. Y. Effect of the Impurity LixNi1−xO on the Electrochemical Properties of 5V Cathode Material LiNi0.5Mn1.5O4. J. Alloys Compd. 2011, 509, 9377–9381.

(27)

Xiao, J.; Chen, X.; Sushko, P. V; Sushko, M. L.; Kovarik, L.; Feng, J.; Deng, Z.; Zheng, J.; Graff, G. L.; Nie, Z.; et al. High-Performance LiNi0.5Mn1.5O4 Spinel Controlled by Mn3+ Concentration and Site Disorder. Adv. Mater. 2012, 24, 2109–2116.

(28)

Lee, E.; Persson, K. a. Revealing the Coupled Cation Interactions behind the Electrochemical Profile of LixNi0.5Mn1.5O4. Energy Environ. Sci. 2012, 5, 6047–6051.

(29)

Long, D. a. The Raman Effect; 2002; Vol. 8.

(30)

Julien, C. M.; Gendron, F.; Amdouni, a.; Massot, M. Lattice Vibrations of Materials for


18

Page 19 of 20

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


Lithium Rechargeable Batteries. VI: Ordered Spinels. Mater. Sci. Eng. B Solid-State Mater. Adv. Technol. 2006, 130, 41–48. (31)

Wang, L.; Li, H.; Huang, X.; Baudrin, E. A Comparative Study of Fd-3m and P4332 “LiNi0.5Mn1.5O4.” Solid State Ionics 2011, 193, 32–38.

(32)

Matsui, M.; Dokko, K.; Kanamura, K. Surface Layer Formation and Stripping Process on LiMn2O4 and LiNi1⁄2Mn3⁄2O4 Thin Film Electrodes. J. Electrochem. Soc. 2010, 157, A121–A129.

(33)

Wei, Y.; Kim, K.-B.; Chen, G. Evolution of the Local Structure and Electrochemical Properties of Spinel LiNixMn2−xO4 (0≤x≤0.5). Electrochim. Acta 2006, 51, 3365–3373.

(34)

Song, J.; Shin, D. W.; Lu, Y.; Amos, C. D.; Manthiram, A.; Goodenough, J. B. Role of Oxygen Vacancies on the Performance of LiNi0.5– xMn1.5+ xO4 ( x = 0, 0.05, and 0.08) Spinel Cathodes for Lithium-Ion Batteries. Chem. Mater. 2012, 24, 3101–3109.

(35)

Lin, H. B.; Zhang, Y. M.; Rong, H. B.; Mai, S. W.; Hu, J. N.; Liao, Y. H.; Xing, L. D.; Xu, M. Q.; Li, X. P.; Li, W. S. Crystallographic Facet- and Size-Controllable Synthesis of Spinel LiNi0.5Mn1.5O4 with Excellent Cyclic Stability as Cathode of High Voltage Lithium Ion Battery. J. Mater. Chem. A 2014, No. 111, 11987–11995.

(36)

Liu, R.-R.; Deng, X.; Liu, X.-R.; Yan, H.-J.; Cao, A.-M.; Wang, D. Facet Dependent SEI Formation on the LiNi0.5Mn1.5O4 Cathode Identified by in Situ Single Particle Atomic Force Microscopy. Chem. Commun. 2014, 50, 15756–15759.

(37)

Fang, C. M.; De Wijs, G. A.; Loong, C.-K.; De With, G. Lattice and Local-Mode Vibrations in Anhydrous and Protonized LiMn2O4 Spinels from First-Principles Theory. J. Mater. Chem. 2007, 17, 4908–4913.


19


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Page 20 of 20

TOC Graphic

Mn Ni

Li O1 O2


20

Versatile Approach Combining Theoretical and ... - ACS Publications

Recommend Documents