Defects, Dopants and Sodium Mobility in Na2MnSiO4

Kuganathan, Navaratnarajah; Chroneos, Alexander

doi:10.1038/s41598-018-32856-7

Cited by 35 publications

(32 citation statements)

References 45 publications

(37 reference statements)

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“…The exoergic binding energy suggests that isolated defects have the tendency to form clusters without energy cost. This defect has been observed in a variety of Li, Na and Mg ion battery materials either experimentally or theoretically [4,19,[36][37][38][50][51][52]. Experimental studies show that this defect is mainly due to synthesis conditions and cycling of the as-prepared material.…”

Section: Intrinsic Defect Processesmentioning

confidence: 93%

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

et al. 2019

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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.

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Section: Intrinsic Defect Processesmentioning

confidence: 93%

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

et al. 2019

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“…Establishing ionic transport pathways by experiments is generally difficult. The current methodology has been utilized successfully to study the ionic transport in a variety of ionic oxide materials [22][23][24][25][26][27][28][29]. Vacancy-assisted migration paths were considered for Fe 2+ ions as their Frenkel is the lowest energy process among other Frenkels.…”

Section: Self-diffusion Of Ironmentioning

confidence: 99%

“…To the best of our knowledge, no theoretical work has been reported on the defects, diffusion, and dopants in ilmenite. In previous studies [22][23][24][25][26][27][28][29], defects have been modeled in a variety of ionic oxide materials using different simulation methods. This work uses classical simulation techniques to examine the energetics of intrinsic defects; Fe-ion diffusion; and solutions of RO (R = Ni, Zn, Co, Mn, Ca, Sr, and Ba), R 2 O 3 (R = Al, Mn, Ga, Sc, In, Yb, Y, Gd, and La), and RO 2 (R = Si, Ge, Sn, Zr, and Ce) in…”

Section: Introductionmentioning

confidence: 99%

Theoretical Modeling of Defects, Dopants, and Diffusion in the Mineral Ilmenite

et al. 2019

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The iron titanium oxide ilmenite (FeTiO3) is a technologically and economically important mineral in the industrial preparation of titanium-based pigments and spintronic devices. In this study, atomistic simulation techniques based on classical pair potentials are used to examine the energetics of the intrinsic and extrinsic defects and diffusion of Fe2+ ions in FeTiO3. It is calculated that the cation anti-site (Fe‒Ti) cluster is the most dominant defect, suggesting that a small amount of cations exchange their positions, forming a disordered structure. The formation of Fe Frenkel is highly endoergic and calculated to be the second most stable defect process. The Fe2+ ions migrate in the ab plane with the activation energy of 0.52 eV, inferring fast ion diffusion. Mn2+ and Ge4+ ions are found to be the prominent isovalent dopants at the Fe and Ti site, respectively. The formation of additional Fe2+ ions and O vacancies was considered by substituting trivalent dopants (Al3+, Mn3+, Ga3+, Sc3+, In3+, Yb3+, Y3+, Ga3+, and La3+) at the Ti site. Though Ga3+ is found to be the candidate dopant, its solution enthalpy is >3 eV, suggesting that the formation is not significant at operating temperatures.

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“…To optimize the performance of Li ion batteries, a more detailed fundamental understanding of existing materials is necessary. Computational modelling techniques have significantly contributed to the characterization of experimental structures, prediction of pathways of migrating ions and identification of promising dopants in a variety of oxide materials [21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36]. In the present study, we examine the intrinsic defects process, Li ion diffusion paths and the effect of dopants on the Mn site in Li 2 MnO 3 .…”

Section: Introductionmentioning

confidence: 98%

Defect Process, Dopant Behaviour and Li Ion Mobility in the Li2MnO3 Cathode Material

et al. 2019

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Lithium manganite, Li2MnO3, is an attractive cathode material for rechargeable lithium ion batteries due to its large capacity, low cost and low toxicity. We employed well-established atomistic simulation techniques to examine defect processes, favourable dopants on the Mn site and lithium ion diffusion pathways in Li2MnO3. The Li Frenkel, which is necessary for the formation of Li vacancies in vacancy-assisted Li ion diffusion, is calculated to be the most favourable intrinsic defect (1.21 eV/defect). The cation intermixing is calculated to be the second most favourable defect process. High lithium ionic conductivity with a low activation energy of 0.44 eV indicates that a Li ion can be extracted easily in this material. To increase the capacity, trivalent dopants (Al3+, Co3+, Ga3+, Sc3+, In3+, Y3+, Gd3+ and La3+) were considered to create extra Li in Li2MnO3. The present calculations show that Al3+ is an ideal dopant for this strategy and that this is in agreement with the experiential study of Al-doped Li2MnO3. The favourable isovalent dopants are found to be the Si4+ and the Ge4+ on the Mn site.

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Defects, Dopants and Sodium Mobility in Na2MnSiO4

Cited by 35 publications

References 45 publications

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

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

Theoretical Modeling of Defects, Dopants, and Diffusion in the Mineral Ilmenite

Defect Process, Dopant Behaviour and Li Ion Mobility in the Li2MnO3 Cathode Material

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