In-situ tritium release (CORELLI-2 experiment) and ex-reactor ionic conductivity of substoichiometric LiAlO2 breeder ceramics

Alessandrini, F.; Alvani, C.; Casadio, S.; Mancini, M.R.; Nannetti, C.A.

doi:10.1016/0022-3115(95)00075-5

Cited by 19 publications

(22 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Previous studies have highlighted the importance of atomic scale calculation to gain insights on the defect processes (intrinsic defect processes, doping and diffusion) of oxides for energy applications [11][12][13][14][15]. Previous experimental and theoretical studies determined a wide range of activation energies for Li self-diffusion in γ-LiAlO 2 (0.50-1.26 eV) [16][17][18][19][20][21][22]. Additionally, there are no systematic studies of the intrinsic defect processes and doping in this material.…”

Section: Introductionmentioning

confidence: 99%

Atomistic Simulations of the Defect Chemistry and Self-Diffusion of Li-ion in LiAlO2

et al. 2019

View full text Add to dashboard Cite

Lithium aluminate, LiAlO 2 , is a material that is presently being considered as a tritium breeder material in fusion reactors and coating material in Li-conducting electrodes. Here, we employ atomistic simulation techniques to show that the lowest energy intrinsic defect process is the cation anti-site defect (1.10 eV per defect). This was followed closely by the lithium Frenkel defect (1.44 eV per defect), which ensures a high lithium content in the material and inclination for lithium diffusion from formation of vacancies. Li self-diffusion is three dimensional and exhibits a curved pathway with a migration barrier of 0.53 eV. We considered a variety of dopants with charges +1 (Na, K and Rb), +2 (Mg, Ca, Sr and Ba), +3 (Ga, Fe, Co, Ni, Mn, Sc, Y and La) and +4 (Si, Ge, Ti, Zr and Ce) on the Al site. Dopants Mg 2+ and Ge 4+ can facilitate the formation of Li interstitials and Li vacancies, respectively. Trivalent dopants Fe 3+ , Ni 3+ and Mn 3+ prefer to occupy the Al site with exoergic solution energies meaning that they are candidate dopants for the synthesis of Li (Al, M) O 2 (M = Fe, Ni and Mn) compounds.Energies 2019, 12, 2895 2 of 10 Computational MethodsThe present computational study was based on classical pair-wise potential calculations to describe LiAlO 2 via the General Utility Lattice Program (GULP) code [23,24]. In the present approach, the total energy (lattice energy) is determined by long range (i.e., Coulombic) and short range [i.e., electron-electron repulsive and attractive intermolecular forces (van der Waals forces)]. The latter were modelled using Buckingham potentials (refer to the supplementary information). The van der Waals forces arising from the spontaneous formation of instantaneous dipoles are very important as the formation energy results are sensitive to those forces. The present modelling approach takes into the account of Van der Waals forces as a function of the interatomic distance (r) [23,24]. Two-body Buckingham potential mentioned in the supplementary information consists of two parts. The first part of the equation represents the Pauli repulsion (electron-electron) and the second part denotes the van der Waals interaction. Ionic positions and lattice parameters were relaxed using the Broyden-Fletcher-Goldfarb-Shanno (BFGS) algorithm [24]. Convergence criteria dictated that in relaxed configurations, forces on each atom was <0.001 eV/Å. To introduce point defects in the lattice we used the Mott-Littleton methodology [25] similarly to recent work [26][27][28]. It is established that although the present methodology may overestimate the defect formation enthalpies at the dilute limit, the trends will be unchanged [29]. In a thermodynamic perspective defect parameters can be described by comparing the real (i.e., defective) crystal to an isobaric or isochoric ideal (i.e., non-defective) crystal. Defect formation parameters can be interconnected through thermodynamic relations [30,31], with the present atomistic simulations corresponding to the isobaric parameters for the mig...

show abstract

Section: Introductionmentioning

confidence: 99%

Atomistic Simulations of the Defect Chemistry and Self-Diffusion of Li-ion in LiAlO2

et al. 2019

View full text Add to dashboard Cite

show abstract

“…Furthermore, the activation energy for conductivity of the lithium rich sample is slightly lower than for the stoichiometric one. The influence of Li/Al ratio on the ionic conductivity of c-LiAlO 2 ceramics has also been reported in other references [13][14][15][16], it was also deduced that Li þ ion diffusivity was increased when Li/Al atomic ratio of the ceramics was increased, which would be attributed mainly to the formation of the highly conductive Li 5 AlO 4 phase. It is remarkable that the lithium deficient sample, i.e., the sample prepared in an open container and annealed for longer time also showed improved ionic conductivity in comparison with the stoichiometric specimen, about 1 order of magnitude higher at 400°C.…”

Section: Phase and Particle Morphologymentioning

confidence: 61%

“…It is remarkable that the lithium deficient sample, i.e., the sample prepared in an open container and annealed for longer time also showed improved ionic conductivity in comparison with the stoichiometric specimen, about 1 order of magnitude higher at 400°C. It should be pointed out that the lithium ion conductivity of the low Li/Al ratio phase LiAl 5 O 8 is several orders of magnitude lower than the stoichiometric c-LiAlO 2 phase [16]. The high conductivity of lithium deficient c-LiAlO 2 phase in this work might be ascribed to some defects probably formed in c-LiAlO 2 phase which are favorable to lithium ion conduction.…”

Section: Phase and Particle Morphologymentioning

confidence: 87%

Research on the preparation, electrical and mechanical properties of γ-LiAlO2 ceramics

Zhang

et al. 2004

Journal of Nuclear Materials

View full text Add to dashboard Cite

“…With the help of solid-state NMR, the microscopic aspects of ionic diffusion are probed, while the macroscopic diffusion parameters are obtained from IS. Apart from studies with other methods [16][17][18] cally characterized using a LECO EF-TC 300 N 2 /O 2 analyzer (hot gas extraction) for oxygen content determination.…”

Section: Introductionmentioning

confidence: 99%

NMR and Impedance Spectroscopy Studies on Lithium Ion Diffusion in Microcrystallineγ-LiAlO₂

Witt

Nakhal

Chandran

et al. 2015

Zeitschrift Für Physikalische Chemie

View full text Add to dashboard Cite

Abstract:In this work nuclear magnetic resonance (NMR) and impedance spectroscopy (IS) studies on Li ion dynamics in microcrystalline -LiAlO 2 are presented. The sample was prepared by solid state synthesis between Li 2 CO 3 and Al 2 O 3 in air, followed by a quenching procedure. The presence of phase-pureLiAlO 2 was confirmed by X-ray powder diffraction including Rietveld refinement.Further structural characterization was done with 6 Li, 7 Li and 27 Al NMR. Several NMR techniques such as spin-lattice relaxation measurements, motional narrowing experiments, as well as spin-alignment echo were employed for the investigation of Li ion diffusion. The measurements were carried out at high temperatures (up to 970 K) in order to access the regime of Li ion motion being very slow. The dc conductivities measured by IS in the temperature range from 680 K to 870 K were converted to diffusion coefficients being compatible with those obtained by NMR.

show abstract

In-situ tritium release (CORELLI-2 experiment) and ex-reactor ionic conductivity of substoichiometric LiAlO2 breeder ceramics

Cited by 19 publications

References 9 publications

Atomistic Simulations of the Defect Chemistry and Self-Diffusion of Li-ion in LiAlO2

Atomistic Simulations of the Defect Chemistry and Self-Diffusion of Li-ion in LiAlO2

Research on the preparation, electrical and mechanical properties of γ-LiAlO2 ceramics

NMR and Impedance Spectroscopy Studies on Lithium Ion Diffusion in Microcrystallineγ-LiAlO₂

Contact Info

Product

Resources

About

In-situ tritium release (CORELLI-2 experiment) and ex-reactor ionic conductivity of substoichiometric LiAlO2 breeder ceramics

Cited by 19 publications

References 9 publications

Atomistic Simulations of the Defect Chemistry and Self-Diffusion of Li-ion in LiAlO2

Atomistic Simulations of the Defect Chemistry and Self-Diffusion of Li-ion in LiAlO2

Research on the preparation, electrical and mechanical properties of γ-LiAlO2 ceramics

NMR and Impedance Spectroscopy Studies on Lithium Ion Diffusion in Microcrystallineγ-LiAlO2

Contact Info

Product

Resources

About

NMR and Impedance Spectroscopy Studies on Lithium Ion Diffusion in Microcrystallineγ-LiAlO₂