Wednesday 10 July 2013, Strathblane & Cromdale Halls, 16:30-18:30
Poster session B -Batteries and fuel cells
P.001 Structure – transport relationship in model systems for fuel cells electrolytes
Q Berrod1, S Lyonnard1, A Guillermo1, G Gebel1, J-M Zanotti2, J Ollivier3 and B Frick3
1
CEA / DSM / INAC / SPrAM, France, 2CEA / DSM / IRAMIS / LLB, France, 3ILL, France
The Nafion is the benchmark membrane used as electrolyte in Proton Exchange Membrane Fuel Cells since many
years. The transport properties are closely related to the dynamical properties of water confined inside this
perfluorinated sulfonic polymer. A deep molecular understanding of the structure/transport interplay has not been
achieved yet, and the complex multi-scale Nafion structure is still under debate. Therefore, we developed a new
approach based on model perfluorinated sulfonic surfactants, to systematically correlate the proton dynamics to a
well-defined nanostructure.
These surfactants self-assemble in water, and form organised phases (lamellar, hexagonal).We have investigated
the structure and the dynamical properties of water confined in these model phases respectively by SANS/SAXS
and QENS [1]. ToF and Backscattering experiments have been combined to cover an extended dynamical range
(IN5 and IN16 at ILL). The QENS spectra have been analysed with a new model for localized translational motions
[2]. The characteristic times, and proton/water diffusion coefficients, obtained in various geometries as a function
of confinement sizes, can be interestingly compared to those of real membranes as Nafion.
[1]
[2]
S. Lyonnard, Q. Berrod, et al., The European Physical Journal, 189, 205-216 (2010)
Volino et al., J. Phys. Chem. B 110, 11217-11223 (2006)
P.002 In-situ neutron diffraction analysis of Li-ion batteries at the IBR-2 pulsed reactor
I Bobrikov1, A Balagurov1, C-W Hu2, C-H Lee2 and D Sangaa1
1
JINR, Russia, 2National Tsing-Hua University, Taiwan
In situ neutron diffraction experiments were performed at HRFD TOF-diffractometer (IBR-2 pulsed reactor, JINR) to
characterize the entire battery system based on LiFePO4 and LiFePO4·VOx electrodes during electrochemical cycling
and to find additional information about crystal structure of electrodes. Another purpose of this work was checking
possibilities for in-situ experiments with real Li-ion batteries at the IBR-2 pulsed reactor. The important option of the
HRFD diffractometer is a possibility to utilize both high-intensity and high-resolution modes without any changes in
the geometry of an experiment. Three full charge/discharge cycles were realized at room temperature (~17oC) with
slow rate. The step-like appearance of several LiCn phases was observed and the volume fractions of LiFePO4 and
FePO4 structural phases at different states of charge were determined. It was shown that charge/discharge process
of LiFePO4 based real Li-ion battery can be effectively studied by time-of-flight technique at the IBR-2 pulsed
reactor.
ICNS 2013 International Conference on Neutron Scattering
P.003 Proton dynamics of triethylammonium triflate probed by neutrons
T Burankova1, J Embs1, V Fossog2 and R Hempelmann2
1
Paul Scherrer Institut, Switzerland, 2Universität des Saarlandes, Germany
Protic ionic liquids are an important group of molten salts, which can form a hydrogen-bond network with protondonor and proton-acceptor sites. The knowledge about their proton transport properties is crucial for a variety of
electrochemical applications. Neutron scattering techniques are sensitive to the presence of hydrogen atoms and
thus can provide useful information about proton dynamics in a sample.
Here we report both elastic scans measurements and QENS-experiments on a protic ionic liquid (triethylammonium
triflate, [NH(C2H5)3][CF3SO3]) performed on the IN10 and IN5 spectrometers at ILL and FOCUS at SINQ on different
time-scales by choosing the corresponding linewidth of the resolution function. The temperature range considered
during the experiments (2-440 K) encompasses the regions where the sample undergoes several phase transitions
with the corresponding changes in the global and localized dynamics of the cation. At higher temperatures all the
following types of motions contribute to the quasielastic broadening: long-range ion diffusion, diffusion in a cage
formed by the neighboring particles, ethyl groups librations, etc.; they are gradually switched off with the
temperature decrease. In order to separate the motions of the cation as a whole and localized dynamics of the side
chains a sample with the deuterated ethyl-groups was investigated as well.
P.004 The contribution of neutron diffraction to the investigation of h2s resistant electrodes for innovative fuel cell
systems
R Coppola1, L Laversenne2, A Moreno1, J Rodriguez-Carvajal3 and E Simonetti1
1
ENEA-Casaccia, Italy, 2CNRS/UJF Grenoble, France, 3ILL, France
The results of a neutron diffraction study of NiCr/CeO2 electrodes for innovative fuel cell systems resistant to H2S are
presented . The anode substrate is constituted by porous Ni- Cr 5% wt; the surface layer is obtained by sol-gel
technique from the CeO2 precursors followed by final heating at 650°C in N2 – H2 3%. Electrochemical
studies showed that the rare-earth metal oxide addition improved the poisoning resistance even though different
mechanisms can be expected at higher H2S concentration and/or higher exposure current density.The neutron
diffraction measurements were carried out at the high intensity diffractometer D20 at the High Flux Reactor of the
ILL - Grenoble, at room temperature, with a neutron wavelength of 0.136 nm. The as-received electrode was
investigated both in a quasi-cylindrical shape of slabs stacked together and as a powder, obtaining nearly identical
results. Data analysis was performed using the Rietveld method with the FullProf Suite program allowing the
characterization of the different phases present in the electrode in a quite accurate way. The substrate, NiCr (Fm3m)
appears as the majority phase with a volume fraction of 68.5%. NiO is detected in addition to NiCr phase as a
consequence of oxidation of the substrate during heating. The volume fraction of NiO is calculated to be 25.3% and
both nuclear and magnetic (light green) contributions have been described. CeO2 appears in the (Fm3m) cubic
structure with as a nano-structured phase The volume percentage of CeO2 layer is determined to be 6.2%. These
results are presented and discussed in view of their usefulness for future measurements of treated electrodes as
well as for in-situ measurements.
ICNS 2013 International Conference on Neutron Scattering
P.005 Structure and dynamics of a new Brownmillerite phases Sr2ScGaO5, promising oxygen ion conductor at
moderate temperature
W Paulus5, S Corallini1, M Ceretti2, C Ritter3, M Zbiri3, A Piovano3 and G Silly4
1
Université Montpellier2, ICGM, France, 2UM2, ICGM, France, 3ILL, France, 4ChV, IC2M, France, 5C2M, ICGM, France
Brownmillerite type oxides have an important role in the field of low temperature oxygen ion conductors. Studies on
these structures showed that the low-temperature oxygen mobility is a result of a phonon assisted diffusion
mechanism based on a dynamic oxygen disorder scenario of the infinite MO4 chains [1-2].
We synthesized a new phase Sr2ScGaO5 (SSGO), containing 3d0 transition elements to have pure oxygen ion
conduction. Depending on the synthesis route, it shows two polymorphs: orthorhombic Brownmillerite type structure
or an oxygen deficient Perovskite structure.
Neutron powder diffraction (D2B@ILL) as a function of temperature (RT-1000°C) revealed the Brownmillerite type
SSGO adopts a quite unusual order: the Sc occupies exclusively the octahedral sites while Ga the tetrahedral ones.
This local environment is confirmed by the NMR analysis coupled with the oxygen isotope exchange 16O-17O.
Moreover SSGO undergoes a phase transition from ordered I2mb (at RT) to disordered Imma at 230°C. In this
sense SSGO can be considered a key compound to probe the influence of order-disorder phenomena in the low
temperature oxygen mobility properties. Inelastic neutron scattering (IN6@ILL) and Raman spectra showed that this
structural change is associated with significant modification in the lattice dynamics related to the oxygen mobility.
[1]
[2]
Le Toquin R., et al., J. Am. Chem. Soc, 2006, 128, 13161–13174
Paulus W., et al., J. Am. Chem. Soc, 2008, 130, 16080–16085
P.006 Phonons and superionic behavior in LiXPO4 (X=Mn,Fe)
P Goel1, M K Gupta1, R Mittal1, S L Chaplot1, S Rols2, S N Achary1 and A K Tyagi1
1
Bhabha Atomic Research Centre, India, 2Institut Laue Langevin, France
Lithium transition metal phosphor-olivines are useful electrode materials, owing to their stability, safety, low cost
and cyclability. Earlier we studied (Phys. Rev. B 85, 184304 (2012)) probable pathways of Li diffusion in Li2O. Here
we report phonon studies on LiXPO4 (X=Mn,Fe) to understand the mechanism and pathways of Li diffusion. The
inelastic neutron scattering measurements were performed with incident neutron energy of 14.2 meV using IN4C
spectrometer at ILL, Grenoble. The experimental data are in excellent agreement with the phonon spectra as
calculated using ab-initio as well as a potential model. The calculations indicate instability of a zone centre mode at
a volume corresponding to about 1000 K in LiFePO4, and at 500 K in LiMnPO4. The unstable phonon mode shows
mainly large vibration of Li atoms in the b-c plane of the orthorhombic structure (space group Pnma). Molecular
dynamics simulations at above these temperatures indicate large diffusive behavior of Li as compared to other
atoms. The neutron measurements also show that the intensity of low energy peak around 5 meV in both the
compounds have significant Q dependence, indicating that they may arise from paramagnetic spin fluctuations.
ICNS 2013 International Conference on Neutron Scattering
P.007 The study of the structure for Li2-xMnO3
L He1, R Wang1, J Chen2, H Li1 and F Wang1
1
Institute of Physics, Chinese Academy of Sciences, China 2Institute of High Energy Physics, Chinese Academy of
Sciences, China
Li-rich Mn-based layered materials with a chemical composition of xLi[Li1/3Mn2/3]O2·(1–x)LiMO2 (M=Mn, Ni, etc.)
has attracted wide attention for its high-energy densities over 300 Wh/kg and good thermal stability in the charged
state.The parent compound Li2MnO3 plays a key role in these materials and a clear understanding on its structure
could be helpful to clarify the complex behaviors of the Li-rich Mn-based layered materials.
Neutron diffraction experiments for partially delithiated and lithiated Li2MnO3 performed on POWGEN3 at SNS. The
refined results show the volume of the unit cell only increases about 0.2% after the chemical delithiation.The Li at
2c and 4h sites are extracted out while the 2b sites are proposed to be fully occupied. The extraction of lithium ions
involves the simultaneous small removal of oxygen ions.
P.008 Dispersion morphology of nafion in the fabrication of fuel cell membrane electrode assemblies
R Hjelm1, C Welch1, A Labouriau1, B Orler2 and Y S Kim1
1
Los Alamos National Laboratory, USA, 2Virginia Tech University, USA
Modern polymer electrolyte fuel cells (PEFCs) require technologies that generate higher performance, durability and
component structural integrity. The membrane electrode assemblies (MEAs) of PEFCs typically contain a Pt/carbon
back catalyst and an ionomer, Nafion. In one process MEAs are produced by solution casting from an ink, a dilute
solution of Nafion and catalyst. Based on the hypothesis that the properties of the MEA are dependent on the
Nafion morphology in the ink from which it is cast, we used small-angle neutron scattering (SANS) to determine the
morphology of Nafion®212 (EW=1000, Na+form) in dilute solutions with different solvents. As the solvents chosen
had different solubility parameters, the interactions with the hydrophilic and hydrophobic parts of Nafion were
anticipated to result in different dispersion morphology. This approach led us to explore the effects of more solvents
than reported in the literature. In contrast to previous results, our combination of SANS (conducted at LANSCE’s
SANS instrument, LQD) and 19F NMR measurements showed that the Nafion structures formed in different solvent
types fall into one of three classes that can be explained by equilibrium and non-equilibrium thermodynamics: i)
Well-defined dispersions with cylindrical Nation morphology with different degrees of solvent penetration; ii) highly
solvated poorly defined large particles; and iii) a random-coil conformation. We will discuss the interesting
correlations between Nation dispersion morphology and critical MEA properties, which are consistent with the
hypothesis.
P.009 Understanding degradation mechanisms of LiNi0.5Co0.2Mn0.3O2 cathode material in lithium ion batteries
S-K Jung1, H Kim1, H Gwon2, J Hong1, K-Y Park1, D-H Seo1, H Kim1 and K Kang1
1
Seoul National University, Korea, 2KAIST, Korea
LiNixCoyMnzO2 (NCM, 0 < x,y,z < 1) has become one of the most important cathode materials for next generation
lithium ion batteries. While the high voltage operation of NCM ( > 4.3 V) is required for a higher capacity, it
inevitably accompanies seriously higher capacity fading over cycle. Here, we investigate the degradation
mechanisms of LiNi0.5Co0.2Mn0.3O2 during the cycling at various charge cut-off voltage conditions. We find that the
transformation of surface crystal structure of the LiNi0.5Co0.2Mn0.3O2 does occur over cycles, which contributes a
gradual increase of charge transfer resistance. The surface of the original rhombohedral phase transformed into a
mixture of spinel and rock salt phases. Furthermore, the formation of the rock salt phase on the surface was more
ICNS 2013 International Conference on Neutron Scattering
dominant with a higher voltage operation ( 4.8 V), which we believe is due to the highly oxidative environment that
triggers the oxygen loss from the surface of the material. The presence of the ionically insulating rock salt phase on
the surface may cause a sluggish kinetics, thus, reduce the capacity. It implies that the prevention of the surface
crystal transformation at the high voltage can provide a way to the high capacity and stable cycle life of
LiNi0.5Co0.2Mn0.3O2
P.010 New iron-based mixed-phosphate cathodes for sodium and lithium rechargeable batteries
H Kim1, I Park1, D-H Seo1, S Lee2, Y-U Park1, S-K Jung1 and K Kang1
1
Seoul National University, Korea, 2Korea Atomic Energy Research Institute, Korea
The key issue to the success of large-scale energy storage systems lies in the advancement of electrode materials
for rechargeable battery. However, the high cost and safety concerns regarding conventional electrodes have so far
prohibited their wide usage in large-scale applications. In this respect, the search for new iron-based polyanion
cathodes is a timely significance. While, the olivine structured material such as LiFePO 4 is the current most
promising material for lithium batteries,[1] recent studies in polyanion materials with a Fe2+/Fe3+ redox couple have
been identified new promising cathodes such as Li2FePO4F,[2] LiFeSO4F,[3] Li2FeP2O7 [4] and LiFeBO3.[5]However,
synthesis of flurinated compounds and lithium iron borate requires complex and costly procedures, and their
theoretical capacity are hardly obtainable. Furthermore, pyrophosphate-based materials could not provide sufficient
specific capacity less than 110mAhg-1
To address these issues, we have proposed new iron-based cathodes, LixNa4-xFe3(PO4)2(P2O7), and successfully
synthesized them. Reversible electrode operation was found in both Li and Na cells with capacities of 140mAhg -1
and 129mAhg-1, respectively. The careful structural investigation using combined neutron and X-ray diffraction
analysis was performed for the detailed structural analysis of NaxFe3(PO4)2(P2O7). The structural evolution during
charge/discharge was also characterized using first principles calculations and neutron diffraction.
[1]
[2]
[3]
[4]
[5]
S. -Y. Chung et al., Nat. Mater. 2002, 1, 123-128
B. L. Ellis et al., Nat. Mater. 2007, 6, 749-753
N. Recham et al., 2009, 9, 68-74
S. Nishimura et al., 2010, 132, 13596-13597
A. Yamada et al., 2010, 22, 3583-3587
P.011 Density of states and anharmonic motion of Si in the MAX phase Ti 3SiC2
O Kirstein1, G Kearley2, V Gray3, D P Riley4, O Kirstein1, R Kutteh2 and E H Kisi3
1
European Spallation Source, Sweden, 2The Bragg Institute, ANSTO, Australia, 3University of Newcastle,
Australia, 4Institute of Materials Engineering, ANSTO, Australia
Recently there has been considerable interest in layered ternary carbides and nitrides of generic form Mn+1AXn,
referred to as MAX phases where M is an early transition metal, A is a group IIIA or IVA element, and X is C or
N. These materials seem to combine the favourable properties of metals (good thermal and electrical conduction,
machinability, and thermal shock resistance) with those of ceramics (good resistance to chemical attack, oxidation
and creep [1]), leading to potential applications in energy generation, chemical processing, and medicine [2].
Recently, experimental data suggested a significant anisotropy of the elastic constants of Ti 3SiC2 [3] which is in
contrast to ab-initio calculations published for the same compound [4]. Observed differences between measured
and calculated elastic constants for Ti3SiC2 are investigated using Density Functional Theory (DFT), DFT Molecular
Dynamics (MD) and Inelastic Neutron Scattering (INS). The DFT-MD shows multiple site occupancy of the Si atoms
within the basal plane at finite temperature and offers an explanation for the failure of elastic constants, calculated
based on the harmonic approximation.
ICNS 2013 International Conference on Neutron Scattering
[1]
[2]
[3]
[4]
Barsoum M W 2000 Prog. Solid State Ch.28 201-281
Eklund P, Beckers M, Jansson U, Hogberg H and Hultman L 2010 Thin Solid Films518 1851-1878
Kisi E H, Zhang J F, Kirstein O, Riley D P, Styles M J and Paradowska A M 2010 J. Phys.:Condensed Matter
22 162202
Cover M F, Warschkow O, Bilek M M M and McKenzie D R 2008 Adv. Eng. Mater.10 935-938
P.012 Investigation of Phase Transitions of vanadium-added LiFePO4 - based Li-Ion Batteries by Real-time
Diffraction Techniques
C-H Lee1, C-W Hu1, I Bobrikov2, A Balagurov2, N Sharma3, H-C Su4, V Peterson5, B-Y Shew4 and D A Balagurov2
1
National Tsing Hua University, Taiwan, 2Frank Laboratory of Neutron Physics, JINR, Russia, 3University of New South
Wales, Sydney, 4National Synchrotorn Radiation Research Center, Taiwan, 5Australian Nuclear Science and
Technology Organisation, Australia
LiFePO4 (LFP) has attracted increasing attention in both academic and industrial communities due to its appealing
electrochemical features including excellent chemical and thermal stability, low material cost, non-toxicity as well as
a high theoretical capacity [1]. In this study, the phase transitionsof the cathode, LFP and vanadium added LFP,
were investigated by in-situ neutron and X-ray powder diffraction. In general, for a two-phase (triphylite and
heterosite) transition process under close-to equilibrium condition (slow rate) during charge/discharge process, the
two-phase co-existence region should be synchronized with a plateau in the charge/discharge curve. However,
previous x-ray-diffraction based reports [2] found evidence of a delayed phase transition, which is a phenomenon
related to the non-synchronization between the phase evolution (phase fraction) and the percentage of Li-ions
transferred during electrochemical cycles. In our study of a vanadium-added LiFePO4 cathode does not exhibit a
delayed phase transition between triphylite and heterosite by real-time neutron powder diffraction, while nonsynchronized phase transition has been found under 0.1 C by real-time x-ray powder diffraction with the nonsynchronize phase transition being significantly reduced by about 20% after V added to LFP. We suggest that the
delayed phase transition can be suppressed through the use of vanadium-added LiFePO4 cathodes. The
discrepancy between in-situ neutron and X-ray diffraction experiments might be due to different volumes being
probed in the sample.
[1]
[2]
A. K. Padhi et al., J. Electrochem. Soc. 7 (1997) 1188
H. H. Chang et al., Electrochm. Commun. 10(2008)335
P.013 Correlation between crystal and magnetic structure of electrode material for 2nd battery
S Lee1, H Kim2 and K Kang2
1
KAERI, Korea, 2Seoul National University, Korea
Crystal and Magnetic structure of 2nd battery electrode materials using neutron power diffraction is essential
because of its sensitivity to observe the light element atom such as Li, Na and O. It is very important to define a
position and occupation of conduction ion(Li-ion) for recognizing their reaction mechanisms. To do further
advanced research combined Rietveld refinement and MEM (Maximum Entropy Method) is revealed the useful
information such as the nuclear density distribution of Li-ion is necessary for understanding the conduction
mechanism.
By detailed structural analysis of electrode materials for rechargeable battery with neutron powder diffraction, we
can recognize the conduction mechanism in an iso-structural change point of view such as an oxygen ion tilting, a
change of bond distance and an occupation variation etc. We can easily see this kind of iso-structural change in
electrode due to the charging/discharging, size-control, doping process and spin ordering. The understanding of
structure change as functions of several external conditions is very substantial to realize next generation 2 nd battery
ICNS 2013 International Conference on Neutron Scattering
with high-capacity, high-efficiency and good-safety. In this study, we have investigated the magnetic and crystal
structure of electrode NaxFe3(PO4)2(P2O7) using neutron powder diffraction. Even though the spin ordering of this
material is observed at a very low temperature, the imagining about correlation between crystal and magnetic
structure in electrode can be given us the clue to realize the new concept’ 2nd battery which the conduction
performance of electrode can be controlled by the spin ordering of magnetic ion.
P.014 Quasielastic neutron scattering study on dynamics of water and ammonia molecules confined in porous
coordination polymers
S Miyatsu1, M Kofu1, M Sadakiyo2, T Yamada3, H Kitagawa4, M Tyagi5, V Garcia-Sakai6, G Simeoni7, W Lohstroh7 and
O Yamamuro1
1
University of Tokyo, Japan, 2I2CNER, Kyushu University, Japan, 3CMS, Kyushu University, Japan, 4Kyoto University,
Japan, 5NCNR, NIST,USA, 6ISIS, STFC,UK, 7FRM-II, TUM, Germany
The dynamics of light molecules confined in nano-porous materials is one of the current topics in condensed matter
physics. We are studying porous coordination polymers (PCPs) as the host material. The merit of PCPs is that pores
of different sizes and geometries can be designed by changing metals and ligands. Here we report on
(NH4)2{HOOC(CH2)4COOH}[Zn2(C2O4)3] and Fe(OH)(bdc-(COOH)2) (bdc = 1,4-benzenedicarboxylate). These
compounds are abbreviated to ZnADP and MIL-53(Fe)-(COOH)2, respectively. The former has layered pores that
adsorb H2O molecules, while the latter forms pore channels that adsorb both H2O and NH3 molecules. Both
materials exhibit high proton conductivity at room temperature; the proton conductivity of ZnADP-3H2O (= 0.01
Scm-1) is as large as that of Nafion known as the best commercial proton conductor. We have performed QENS
measurements on these materials to investigate the dynamics of the confined molecules. Heat capacity and Xray/neutron diffraction measurements were also performed to characterize their phase behavior and structure. In
ZnADP-3H2O, we found four relaxation modes owing to the rotations of H2O molecules and NH4+ ions. Their
activation energies are smaller than 10 kJmol-1, which could be associated with high proton conductivity.
Relaxations were found also in MIL-53(Fe)-(COOH)2-2H2O and MIL-53(Fe)-(COOH)2-3NH3. We will present general
discussion on the dynamics of the confined molecules and the mechanism of the proton conduction in PCPs.
P.015 Structural origin of lithium diffusion for Li7P3S11 metastable crystal
Y Onodera1, K Mori1, T Otomo2 and T Fukunaga1
1
Kyoto University, Japan, 2Institute of Materials Structure Science, High Energy Accelerator Research Organization,
Japan
A Li7P3S11 metastable crystal, which can be synthesized by aging of (Li2S)70(P2S5)30 glass at 513K, showed a high
ionic conductivity in the order of 10-3 S/cm at room temperature [1]. And then, the activation energy for ionic
conduction of Li7P3S11 metastable crystal is approximately half of that of (Li2S)70(P2S5)30 glass. In order to elucidate
the relationship between the structure and the excellent electrical properties, we have been visualized threedimensional atomic configurations of 7Li7P3S11 metastable crystal and (7Li2S)70(P2S5)30 glass by reverse Monte Carlo
modeling using time-of-flight neutron diffraction and synchrotron X-ray diffraction data. In addition, it was found
that the number of ac-[S4] units, which are fully acceptable voids of Li+ ions, for 7Li7P3S11 metastable crystal is much
larger than that for (7Li2S)70(P2S5)30 glass in the polyhedral analysis of three-dimensional structures [2].
In this study, we progressed the polyhedral analysis by focusing on “windows”, that is, triangular surfaces, which
form [LiS4] tetrahedral units and strongly related to the Li migration from [LiS4] units to ac-[S4] units. We will show
the results of the polyhedral analysis and discuss the structural origin of the Li+ conduction for the 7Li7P3S11
metastable crystal more deeply in our presentation.
[1]
F. Mizuno et al., Electrochem. Solid-State Lett. 8 (2005) A603
ICNS 2013 International Conference on Neutron Scattering
[2]
Y. Onodera et al., J. Phys. Soc. Jpn. 81 (2012) 044802
P.016 Impact of excess oxygen on the lattice dynamics of Nd2NiO4+x oxides
A Perrichon1, M Ceretti1, W Paulus1, A Piovano2, M Boehm2, M Zbiri2, M Johnson2 and H Schober2
1
UM2, Institut Charles Gerhardt Montpellier, France, 2ILL, France
Nd2NiO4+x crystals, from the Re2MO4+x family of layered overstoichiometric oxides with Re=(La,Nd,Pr) and
M=(Cu,Ni,Co), show room-temperature oxygen mobility and are thus promising candidates for moderatetemperature oxygen conduction devices.
Previous work on related Brownmillerite phases have shown that RT oxygen mobility depends on structural
instabilities coupled to the existence of low energy excitations[1,2]. Meanwhile structural instabilities have been
confirmed for both Nd2NiO4.25 and isostructural Pr2NiO4.25[3] and La2CuO4.07[4].
Long-range ordering of excess oxygen in fully oxidized Nd2NiO4.25 leads to strong nuclear satellites in neutron
diffraction pattern. Underlying extra structural correlations compared to stoichiometric Nd2NiO4.0 are thus expected
to impact on lattice dynamics.
We performed ab initio first principle phonon calculations and molecular dynamics, joint with inelastic neutron
scattering experiments on the thermal-neutron three-axis spectrometers IN8 and IN3, and on the cold-neutron timeof-flight spectrometer IN6 at ILL.
First results show good agreement between simulations and experiments for the heavy-atom host lattice dynamics,
while the excess oxygen induces both broadening and softening of overall oxygen dynamics and additional
contributions up to 2THz.
[1]
[2]
[3]
[4]
Paulus et al. J. Am. Chem. Soc. (2008), 130, 16080-16085
Piovano et al. J. Phys. Chem. C (2011) 115, 1311-1322
Wahyudi, PhD thesis 4468 (2011), Université de Rennes 1
Villesuzanne et al. J. Solid State Electrochem. (2011), 15, 357-366
P.017 Towards room-temperature oxygen diffusion materials: Relation between structural properties and oxygen
diffusion in Perovskites
J Schefer1, J Schefer2, W Paulus3, M Ceretti3, R Sura2, K Conder2, E Pomjakushina2, L Le Dréau4 and B Pederson5
1
Laboratory for Neutron Scattering, Switzerland, 2Paul Scherrer Institut, Switzerland, 3Université de Montpellier 2,
France, 4Bruker AXS, France, 5Forschungs Neutronenquelle Heinz Maier-Leibnitz, France
Only a few oxides are known today which show oxygen-ion conductivity at moderate or even at ambient
temperatures as searched in applications. Among them, two Perovskite-derivatives, the Brownmillerite ABO2.5+δ and
the Ruddlesden-Popper A2BO4+δ phases (for references, see [1]) are of particular interest, as they are nonstoichiometric and are able to accommodate an important amount ( 4%) of oxygen on interstitial or regular lattice
sites.
Specifically La2CoO4+δ and La2NiO4 are highly reactive and surprisingly these phases are able to bound oxygen
spontaneously under ambient conditions. The uptake of oxygen for Brownmillerite-type compounds (ABO2.5) goes
along with the filling-up of 1D oxygen vacancy channels, i.e. regular lattice sites. In contrast, the intercalation of
oxygen in Ruddlesden-Popper K2NiF4 type oxides leads to a partial occupation of interstitial lattice sites. This
implies a principal difference in terms of diffusion pathways and mechanisms for both types of oxides, driven by
order/disorder of the BO6 octahedra. We investigated the structural properties by means of X-ray and neutron single
crystal diffraction [2,3]. Data were analyzed by Maximum Entropy Method (MEM).
ICNS 2013 International Conference on Neutron Scattering
[1]
[2]
[3]
Paulus, W. et. al. (2002). Solid State Sciences 4: 565
Le Dreau, L. (2011). "Phase transistions and oxygen ordering in La2CoO4+d and (T,T') La2CuO4: Single
cyrstal growth and structural studies using synchrotron and neutron diffraction methods." Thesis,
University of Rennes (2012) 4366: 1-258, LNS-report 241
Villesuzanne, A., W. Paulus, A. Cousson, S. Hosoya, L. Le Dréau, O. Hernandez, C. Prestipino, M. I. Houchati
and J. Schefer (2011). J Solid State Electrochem 15: 357-366
P.018 "In operando" neutron scattering studies studies of Li-ion batteries
A Senyshyn1, O Dolotko2, M J Mühlbauer2, K Nikolowski3 and H Ehrenberg3
1
Technische Universität München, Germany, 2 Technische Universität Darmstadt, Germany, 3Karlsruhe Institute of
Technology (KIT), Institute for Applied Materials (IAM), Germany
Due to the rapid progress in the field of portable electronic and electric vehicles there is an increasing demand for
safer, smaller size, larger capacity, lighter weight and lower priced rechargeable batteries. Among various
approaches towards a further improvement, the characterization of the entire battery system during electrochemical
cycling seems to be the most promising one as it gives unique information about processes occurring inside the
battery “live”. “In operando” experiment performed on real industrial cells might be non-destructive and keep all
battery constituents under real operation conditions so that any risks of materials oxidation, electrolyte evaporation
or battery charge changes are eliminated. In this sense neutron scattering is an outstanding tool often having no
alternative, when characterization of complex Li-containing systems is under discussion1.
A combination of available neutron scattering techniques permits the monitoring of various battery parts on different
scale levels. The current contribution primarily concerns the structural aspects of lithium intercalation into graphite
anode and LiCoO2 cathode on example of commercial cell of 18650-type on the basis of combined
electrochemical/high-resolution neutron powder diffraction studies. It unravels novel details of Li intercalation in the
electrode materials and will be discussed in brief along with the influence of fatigue on the crystal structure of
battery electrode materials.
[1]
H. Ehrenberg, A. Senyshyn, M. Hinterstein, H. Fuess (2012). In Situ Diffraction Measurements: Challenges,
Instrumentation, and Examples. In E.J. Mittermeijer & U. Welzel (Eds.), Modern Diffraction Methods.
Weinheim: Wiley-VCH
P.019 Crystal structure transition and cation conductivity in Li4P2O7 polymorph
E Sherstobitova1, V Voronin1, V Blatov2 and G Shekhtman3
1
Institute for Metal Physics, Russia, 2Samara State University, Russia, 3Institute of High Temperature
Electrochemistry, UB RAS, Russia
In the series of Li–P–O ternary compounds, LiFePO4 is one of the most promising candidates for rechargeable lithium
batteries. For example, coating of Li4P2O7 on the surface of nanoscale LiFePO4 provides high ion-conductivity of the
composite [1]. We present the results of a powder neutron diffraction study of the Li4P2O7 crystal structure on
heating from 300 K up to 1050 K and back cooling down to 300 K. Rietveld refinement showed that at room
temperature Li4P2O7 has a triclinic structure (space group P-1) formed by formed by pyrophosphate groups (two
vertex shared PO4 tetrahedra) and highly distorted LiO4 tetrahedra. Upon heating up to 950 K, a reversible phase
transition is observed as indicated by the Bragg peaks evolution at the neutron diffraction pattern. It has been found
that the high temperature phase has a monoclinic structure (space group P21/n). The structural phase transition is
followed by increase of the conductivity and decrease of the activation energy that indicates increased mobility of
the current carriers. The Li-cations migration map has been analyzed by means of the TOPOS program package [2].
ICNS 2013 International Conference on Neutron Scattering
It has been found that most of the lithium conductivity channels are located in the (001) layers.This work was
supported by Russian Foundation for Basic Research (grant No.11-03-00663a)
[1]
[2]
B.Kang, G.Ceder, Nature 458 (2009) 190–193
V. A. Blatov, Struct. Chem. 23 (2012) 955-963
P.020 Researches of size effect in nanocrystalline ceria by means of neutron scattering methods
A Sokolov1, G Kopitsa1, V Ivanov2 and A Baranchikov2
1
Petersburg Nuclear Physics Institute - NRC Kurchatov Institute, Russia, 2Institute of General and Inorganic
Chemistry, Bulgaria
Nanocrystalline ceria could be used in various applications such as fuel cells, ultraviolet protectors, selfregenerating antioxidants. Properties of nanoceria are closely related to crystal sizes. Also the strong negative size
effect on crystal lattice parameter occurs. It is conventional to explain this effect as a result of presence of strong
oxygen nonstoichiometry and corresponding change of oxidation level of cerium ion. However our neutron
diffractometry researches at room temperature detect lack of significant oxygen nonstoichiometry inside the whole
range of sizes, at once point to the probable increase of oxygen thermal mobility with dispersity augmentation. The
additional analysis of neutron diffraction data at ultra-low temperature indicates the occurrence of significant values
of Debye-Waller static factors and the absence of any substantial deviations from the stoichiometric composition for
sizes of coherent scattering regions down to 5 nm.
The small-angle neutron scattering data demonstrate the possibility of mechanism of oriented adhesion and
subsequent coalescence of particles. Researches of the growth process of ceria nanoparticles with modified
surfaces show, that it is utterly sensitive to the chemical prehistory of the powder. Nevertheless, it is established,
that varying of synthesis methods does not affect the lattice parameter of ceria, and the sole determining factor is
the size of particles.
P.021 Real-time investigation of the structural evolution of electrodes in a commercial lithium-ion battery using insitu X-ray and neutron powder diffraction
H Su1, C W Hu2, N Sharma3, C Chiang1, V Peterson4, B Shew1 and C Lee2
1
National Synchrotron Radiation Research Center, Taiwan, 2Department of Engineering and System Science,
National Tsing Hua University, Taiwan, 3School of Chemistry, University of New South Wales, Australia, 4Australian
Nuclear Science and Technology Organisation, Australia
In-situ X-ray and neutron powder diffraction were employed to investigate the structural evolution of the electrode
materials in a commercial lithium-ion battery used for electric buses in Taiwan. The battery contains a vanadiumadded LiFePO4 (LFPV) cathode and a LixC6 anode. This cathode does not exhibit a delayed phase transition between
LiFePO4 (LFPO) and FePO4 (FPO) as the pristine LFPO behaves. This observation suggests that the delayed phase
transition can be suppressed by adding vanadium into LFPO cathodes to enhance the capacity and prolong the
cycle life. The vanadium added cathode may have faster nucleation kinetics of the resulting phases than LFPO
alone, resulting in the synchronization of the phase transition. This supports our previous work [1] that shows
vanadium incorporation into the olivine structure can induce lithium vacancies, which may improve nucleation
kinetics and hence contribute to the suppression of the delayed phase transition. However, many problems of the
mechanism of delayed phase transition at cathode are still chaos for furthermore clarify, such as charge/discharge
rates, type of electrolytes, cycling history of the battery, operating temperature and voltage ranges, and vanadium
ordering must be comparable. About the anode, approximately 75% lithium insertion/extraction occurs in the Li xC6
anode at 0.1 C. This result at the anode shows a normal reversible process during electrochemical cycling.
[1]
C.Y. Chiang et al, J Phys. Chem. C 116 (2012) 24424
ICNS 2013 International Conference on Neutron Scattering
P.022 Crystallographic structure of LiFexMn1-xPO4 solid solutions studied by neutron powder diffraction
F Wang, X Li, Z Zhang, L He and H Li
Institute of Physics Chinese Academy of Sciences, China
High resolution neutron powder diffraction data were recorded on the cathode material LiFe xMn1-xPO4 solid solutions
using HRPD machine at SINQ/PSI, Switzerland. Ab initio crystal structure solution via FOX program indicates
demonstrably that the space group of LiFePO4 is Pnma (No. 62) with Li1+ occupying octahedral (4a) sites and Fe2+
octahedral (4c) sites at the olivine structure. Rietveld refinement (Fullprof program), complementary with Xray
diffraction data, shows that Fe2+ may partially (about 1% 2%) distribute over Li1+ sites, which seemingly lowers the
electronic conductivity of LiFePO4. Neutron powder diffraction data for LiFexMn1-xPO4 (x=0, 0.2, 0.5, 0.8 and 1)
reveals that the Mn2+ replacing Fe2+ at the octahedral (4c) sites. The cell parameters a, b and c increase linearly and
the interatomic distances (in Å) of Fe(Mn)-O(1) and Li-O(1) increase while the interatomic distances (in Å) of LiO(3) decrease on the addition of Mn2+, partially explaining a bit higher potential plateaus of 4.0 eV in LiMnPO4
than 3.5 eV in LiFePO4.
P.023 Quasi-Elastic Neutron Studies of Jump Diffusion in Battery Materials
T Willis1, D Voneshen2, S Uthayakumar2, R Bewley3, R Stewart3, A Boothroyd4 and J Goff2
1
Royal Holloway, University of London, UK, 2Department of Physics, Royal Holloway, University of London, UK, 3ISIS
Facility, Rutherford Appleton Laboratory, UK, 4University of Oxford, UK
LixCoO2 batteries are used commonly in laptops, mobile phones and other portable devices. The scarcity of Li has
led to the proposal of alternative battery materials, and Na-ion batteries are leading contenders. NaxCoO2 has
excellent electrochemical performance and would be cheaper to produce due to the greater abundance of Na over
Li. NaxCoO2 forms a variety of superstructures, dependant on concentration and temperature. A partially ordered
phase occurs at around room temperature and at higher temperatures the system transforms to a fully disordered
phase. The growth of large single crystals of NaxCoO2 using the floating-zone technique has made it possible to
study the diffusion of Na ions using quasi-elastic neutron scattering. We have studied the incoherent quasi-elastic
neutron scattering from Na0.8CoO2 at elevated temperatures using LET at ISIS. The dependence of the energybroadened width of the quasi-elastic scattering on the wave-vector transfer has been analysed and fitted to jump
diffusion models. The temperature dependence of the diffusion rates has been measured and the activation
energies for diffusion processes have been determined.
ICNS 2013 International Conference on Neutron Scattering