scholarly journals A Computational Study of Defects, Li-Ion Migration and Dopants in Li2ZnSiO4 Polymorphs

Crystals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 563 ◽  
Author(s):  
Dilki Perera ◽  
Sashikesh Ganeshalingam ◽  
Navaratnarajah Kuganathan ◽  
Alexander Chroneos
Keyword(s):  
Long Range ◽  
Atomistic Simulation ◽  
Computational Study ◽  
Orthorhombic Phase ◽  
Activation Energies ◽  
Intrinsic Defect ◽  
Li Ion Batteries ◽  
Ion Migration ◽  
Simulation Techniques ◽  
Li Ion

Lithium zinc silicate, Li2ZnSiO4, is a promising ceramic solid electrolyte material for Li-ion batteries. In this study, atomistic simulation techniques were employed to examine intrinsic defect processes; long range Li-ion migration paths, together with activation energies; and candidate substitutional dopants at the Zn and the Si sites in both monoclinic and orthorhombic Li2ZnSiO4 phases. The Li-Zn anti-site defect is the most energetically favourable defect in both phases, suggesting that a small amount of cation mixing would be observed. The Li Frenkel is the second lowest energy process. Long range Li-ion migration is observed in the ac plane in the monoclinic phase and the bc plane in the orthorhombic phase with activation energies of 0.88 eV and 0.90 eV, respectively, suggesting that Li-ion diffusivities in both phases are moderate. Furthermore, we show that Fe3+ is a promising dopant to increase Li vacancies required for vacancy-mediated Li-ion migration, and that Al3+ is the best dopant to introduce additional Li in the lattice required for increasing the capacity of this material. The favourable isovalent dopants are Fe2+ at the Zn site and Ge4+ at the Si site.

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

Energies ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2895 ◽  
Author(s):  
N. Kuganathan ◽  
J. Dark ◽  
E.N. Sgourou ◽  
Y. Panayiotatos ◽  
A. Chroneos
Keyword(s):  
Atomistic Simulation ◽  
Three Dimensional ◽  
Atomistic Simulations ◽  
Intrinsic Defect ◽  
Lithium Content ◽  
Frenkel Defect ◽  
Self Diffusion ◽  
Simulation Techniques ◽  
Lithium Diffusion ◽  
Li Ion

Lithium aluminate, LiAlO2, 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 Mg2+ and Ge4+ can facilitate the formation of Li interstitials and Li vacancies, respectively. Trivalent dopants Fe3+, Ni3+ and Mn3+ prefer to occupy the Al site with exoergic solution energies meaning that they are candidate dopants for the synthesis of Li (Al, M) O2 (M = Fe, Ni and Mn) compounds.

scholarly journals Structural and Defect Properties of LiTi2(PO4)3

2021 ◽  
Vol 11 (5) ◽  
pp. 13268-13275
Keyword(s):  
Atomistic Simulation ◽  
Three Dimensional ◽  
Intrinsic Defect ◽  
Ion Diffusion ◽  
Ion Migration ◽  
Pair Potentials ◽  
Simulation Based ◽  
Engineering Strategy ◽  
Li Ion ◽  
High Chemical Stability

LiTi2(PO4)3 is an attractive electrolyte material in Li-ion batteries' application due to its high ionic conductivity and high chemical stability. Here we employ atomistic simulation based on the classical pair potentials to examine the intrinsic defect processes, Li-ion migration, and solution of various dopants in LiTi2(PO4)3. The Li-Frenkel (0.73 eV) is calculated to be the most favorable defect energy process ensuring the formation of Li vacancies required for the vacancy-assisted Li-ion migration. Long-range three-dimensional lithium vacancy migration was observed with a low activation energy of 0.36 eV, inferring fast Li-ion diffusion. The most favorable isovalent dopants on the Li and Ti sites are Na and Si, respectively. Li interstitials' formation in these materials is favored by doping of Ga on the Ti site. This engineering strategy can be of interest to improve the capacity of LiTi2(PO4)3.

scholarly journals Atomistic Simulation of Intrinsic Defects and Trivalent and Tetravalent Ion Doping in Hydroxyapatite

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Ricardo D. S. Santos ◽  
Marcos V. dos S. Rezende
Keyword(s):  
Atomistic Simulation ◽  
Charge Compensation ◽  
Intrinsic Defect ◽  
Intrinsic Defects ◽  
Simulation Techniques ◽  
Ion Doping ◽  
Key Issues

Atomistic simulation techniques have been employed in order to investigate key issues related to intrinsic defects and a variety of dopants from trivalent and tetravalent ions. The most favorable intrinsic defect is determined to be a scheme involving calcium and hydroxyl vacancies. It is found that trivalent ions have an energetic preference for the Ca site, while tetravalent ions can enter P sites. Charge compensation is predicted to occur basically via three schemes. In general, the charge compensation via the formation of calcium vacancies is more favorable. Trivalent dopant ions are more stable than tetravalent dopants.

scholarly journals Defect, Diffusion and Dopant Properties of NaNiO2: Atomistic Simulation Study

Energies ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 3094 ◽  
Author(s):  
Ruwani Kaushalya ◽  
Poobalasuntharam Iyngaran ◽  
Navaratnarajah Kuganathan ◽  
Alexander Chroneos
Keyword(s):  
Atomistic Simulation ◽  
High Capacity ◽  
Sodium Ion ◽  
Intrinsic Defect ◽  
Sodium Ion Batteries ◽  
Ion Diffusion ◽  
Defect Diffusion ◽  
Simulation Techniques ◽  
Defect Process ◽  
Isovalent Dopant

Sodium nickelate, NaNiO2, is a candidate cathode material for sodium ion batteries due to its high volumetric and gravimetric energy density. The use of atomistic simulation techniques allows the examination of the defect energetics, Na-ion diffusion and dopant properties within the crystal. Here, we show that the lowest energy intrinsic defect process is the Na-Ni anti-site. The Na Frenkel, which introduces Na vacancies in the lattice, is found to be the second most favourable defect process and this process is higher in energy only by 0.16 eV than the anti-site defect. Favourable Na-ion diffusion barrier of 0.67 eV in the ab plane indicates that the Na-ion diffusion in this material is relatively fast. Favourable divalent dopant on the Ni site is Co2+ that increases additional Na, leading to high capacity. The formation of Na vacancies can be facilitated by doping Ti4+ on the Ni site. The promising isovalent dopant on the Ni site is Ga3+.

Insight into fast ion migration kinetics of a new hybrid single Li-ion conductor based on aluminate complexes for solid-state Li-ion batteries

Nanoscale ◽  
2018 ◽  
Vol 10 (13) ◽  
pp. 5975-5984 ◽  
Author(s):  
Yancong Feng ◽  
Rui Tan ◽  
Yan Zhao ◽  
Rongtan Gao ◽  
Luyi Yang ◽  
...  
Keyword(s):  
Polyethylene Oxide ◽  
Transport Mechanism ◽  
Li Ion Batteries ◽  
Ion Migration ◽  
Ion Conductor ◽  
Hopping Transport ◽  
Li Ion ◽  
Fast Ion ◽  
Kinetics Of ◽  
Insight Into

A novel hybrid single Li-ion conductor with high ion migration kinetics was prepared by mixing aluminate complexes–polyethylene glycol and polyethylene oxide. The new hopping transport mechanism was proposed.

scholarly journals Electrochemical Performance of Orthorhombic CsPbI3 Perovskite in Li-Ion Batteries

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5718
Author(s):  
Nahid Kaisar ◽  
Tanmoy Paul ◽  
Po-Wei Chi ◽  
Yu-Hsun Su ◽  
Anupriya Singh ◽  
...  
Keyword(s):  
Electrochemical Performance ◽  
Structural Integrity ◽  
Relaxation Times ◽  
Solution Process ◽  
Orthorhombic Phase ◽  
Metal Foil ◽  
Li Ion Batteries ◽  
Transfer Processes ◽  
Li Ion ◽  
Strained Bonds

A facile solution process was employed to prepare CsPbI3 as an anode material for Li-ion batteries. Rietveld refinement of the X-ray data confirms the orthorhombic phase of CsPbI3 at room temperature. As obtained from bond valence calculations, strained bonds between Pb and I are identified within PbI6 octahedral units. Morphological study shows that the as-prepared δ-CsPbI3 forms a nanorod-like structure. The XPS analysis confirm the presence of Cs (3d, 4d), Pb (4d, 4f, 5d) and I (3p,3d, 4d). The lithiation process involves both intercalation and conversion reactions, as confirmed by cyclic voltammetry (CV) and first-principles calculations. Impedance spectroscopy coupled with the distribution function of relaxation times identifies charge transfer processes due to Li metal foil and anode/electrolyte interfaces. An initial discharge capacity of 151 mAhg−1 is found to continuously increase to reach a maximum of ~275 mAhg−1 at 65 cycles, while it drops to ~240 mAhg−1 at 75 cycles and then slowly decreases to 235 mAhg−1 at 100 cycles. Considering the performance and structural integrity during electrochemical performance, δ-CsPbI3 is a promising material for future Li-ion battery (LIB) application.

Constructing epitaxial grown heterointerface of metal nanoparticles and manganese dioxide anode for high-capacity and high-rate lithium-ion batteries

Nanoscale ◽  
2021 ◽  
Author(s):  
Jianwei Zhang ◽  
Danyang Huang ◽  
Yuchen Wang ◽  
Liang Chang ◽  
Yanying Yu ◽  
...  
Keyword(s):  
Transition Metal Oxides ◽  
Migration Rate ◽  
Anode Materials ◽  
High Capacity ◽  
Lithium Ion ◽  
High Rate ◽  
Metal Particles ◽  
Li Ion Batteries ◽  
Ion Migration ◽  
Li Ion

Low ion migration rate and irreversible change in the valence state in transition-metal oxides limited their application as anode materials in Li-ion batteries (LIBs). Interfacial optimization by loading metal particles...

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