Atomistic Simulation and Characterization of Spinel Li1+xMn2O4 (0 ≤ x ≤ 1) Nanoparticles

Ledwaba, Raesibe S.; Sayle, Dean C.; Ngoepe, Phuti E.

doi:10.1021/acsaem.9b01870

Cited by 17 publications

(19 citation statements)

References 47 publications

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“…The development of interatomic potentials, which requires model parametrization with respect to a set of target observables, is a difficult task for these systems. For layered structures, variations of the Buckingham potential form have been developed, some using rigid-ion models, − and others using core–shell models, − ,,, with a mixture of formal and partial charges. We made attempts to apply the fitting routines from established codes, including the General Utility Lattice Program (GULP), Atomicrex, dftfit, and potfit .…”

Section: Electrons: Oxidation-state Competitionmentioning

confidence: 99%

From Atoms to Cells: Multiscale Modeling of LiNi_xMn_yCo_zO₂ Cathodes for Li-Ion Batteries

et al. 2021

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First-generation cathodes for commercial lithium-ion batteries are based on layered transition-metal oxides. Research on ternary compounds, such as LiCoO2, evolved into mixed-metal systems, notably Li(Ni,Mn,Co)O2 (NMCs), which allows significant tuning of the physical properties. Despite their widespread application in commercial devices, the fundamental understanding of NMCs is incomplete. Here, we review the latest insights from multiscale modeling, bridging between the redox phenomena that occur at an atomistic level to the transport of ions and electrons across an operating device. We discuss changes in the electronic and vibrational structures through the NMC compositional space and how these link to continuum models of electrochemical charge–discharge cycling. Finally, we outline the remaining challenges for predictive models of high-performance batteries, including capturing the relevant device bottlenecks and chemical degradation processes, such as oxygen evolution.

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Section: Electrons: Oxidation-state Competitionmentioning

confidence: 99%

From Atoms to Cells: Multiscale Modeling of LiNi_xMn_yCo_zO₂ Cathodes for Li-Ion Batteries

et al. 2021

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“…The expanded crystal lattice coupled with the ultrafine 0D nanodot structure can make full use of the active siteseven those in the crystal centeras shown in Figure d. Besides, the Jahn–Teller effect may be the other reason, and more lithium ions can be incorporated into the crystal to form Li 1+ x Mn 2 O 4 (0 < x < 1; probably x = 0.25 in our case) while maintaining the spinel structure. , The adsorption isotherms are more consistent with the Langmuir equation than with the Freundlich equation, indicating the homogeneous active sites and the negligible diffusion resistance inside the crystal. The detailed fitting parameters and correlation coefficients can be found in Table S2.…”

Section: Resultsmentioning

confidence: 59%

Hierarchically Porous Polyacrylonitrile (PAN) 3D Architectures with Anchored Lattice-Expanded λ-MnO₂ Nanodots as Freestanding Adsorbents for Superior Lithium Separation

Wang

et al. 2020

Ind. Eng. Chem. Res.

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The search for novel lithium-ion sieves (LISs) with more desirable performance seems to be at the cutting edge of lithium separation from seawater and salt-lake brines. In this work, new types of freestanding shape-controllable LISs have been prepared by subtly anchoring λ-MnO2 nanodots on the surface of mesoporous polyacrylonitrile (PAN) nanoskeletons via a scalable sol–gel method. Synergistic effects originate from the hierarchically porous polymer structure, and the high surface ratio of nanodots significantly reduces ion-diffusion resistance, rendering superior kinetics with the adsorption equilibrium being achieved within 3 h for PMO-1. Moreover, PAN not only acts as a binder but also tunes the λ-MnO2 crystal structure by inhibiting the lattice shrinkage of LiMn2O4 during the acid leaching process. The slightly expanded crystal cell enhances the use of active sites, which ultimately results in an excellent saturated adsorption capacity of 49.0 mg g–1 for PMO-1 (based on the mass of λ-MnO2). Flow-through adsorption tests have also been performed by continuously injecting the solution into a PMO-1-packed column to verify its ability for practical applications, which further prove its robust cycling performance and superior lithium separation properties for both seawater and salt-lake brines.

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“…Herein the high temperature behaviour of LLZO is carefully investigated as an initial step to identifying the high temperature behaviour of this electrolyte material. Subsequently, employment of the armorphization and recrystallization process (Ledwaba et al 2020;Shibiri et al 2019) will be of essence as this process helps with the unique acquisition of the microstructural properties and eventually the prediction of performance-enhancing properties for the ultimate improvement of all solid state batteries.…”

Section: Introductionmentioning

confidence: 99%

Formation of garnet-type Li7La3Zr2O12 nanoparticles as an alternative structural stabilization route

Ledwaba

Ngoepe

2022

SATNT

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The cubic garnet-type Li7La3Zr2O12 (LLZO) is an eminent candidate for next-generation solid state battery technology due to its therma stability and high ionic conductivity. As such, its operation mechanisms need to be thoroughly understood, particularly on the structural nstability challenge reported to occur at lower temperatures. Although it exists as either the tetragonal or cubic structures, the latter is favourable because of its higher Li+ conductivity rate. However, inability to retain thermodynamic stability in cubic phase at low temperatures (≤ 903,15 K) remains a challenge. As an alternative to extrinsic doping, as recently attempted in various studies, it has been discovered that decreasing the size to nano-level could remedy the phase stability challenge of cubic LLZO. Herein, we have modelled the bulk and nanostructured LLZO under various temperature conditions in the range 300 – 1500 K using the DL_ POLY molecular dynamics code, to understand the LLZO high temperature behaviour and track phase transformations. The molecular dynamics calculations performed on these materials revealed two distinct patterns of Li-ion transport on the diffusion coefficient plots. The trends in conductive ion diffusions show that nanostructured materials yield higher diffusion coefficients that the bulk structures. Findings of this study form a strong foundation towards the amorphization and recrystallization of these materials to monitor any change in structure post crystallization since the ability to retain both structural and conductivity rate are equally crucial.

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Atomistic Simulation and Characterization of Spinel Li_1+xMn₂O₄ (0 ≤ x ≤ 1) Nanoparticles

Abstract: The version in the Kent Academic Repository may differ from the final published version. Users are advised to check http://kar.kent.ac.uk for the status of the paper. Users should always cite the published version of record.

Cited by 17 publications

References 47 publications

From Atoms to Cells: Multiscale Modeling of LiNi_xMn_yCo_zO₂ Cathodes for Li-Ion Batteries

From Atoms to Cells: Multiscale Modeling of LiNi_xMn_yCo_zO₂ Cathodes for Li-Ion Batteries

Hierarchically Porous Polyacrylonitrile (PAN) 3D Architectures with Anchored Lattice-Expanded λ-MnO₂ Nanodots as Freestanding Adsorbents for Superior Lithium Separation

Formation of garnet-type Li7La3Zr2O12 nanoparticles as an alternative structural stabilization route

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Atomistic Simulation and Characterization of Spinel Li1+xMn2O4 (0 ≤ x ≤ 1) Nanoparticles

Abstract: The version in the Kent Academic Repository may differ from the final published version. Users are advised to check http://kar.kent.ac.uk for the status of the paper. Users should always cite the published version of record.

Cited by 17 publications

References 47 publications

From Atoms to Cells: Multiscale Modeling of LiNixMnyCozO2 Cathodes for Li-Ion Batteries

From Atoms to Cells: Multiscale Modeling of LiNixMnyCozO2 Cathodes for Li-Ion Batteries

Hierarchically Porous Polyacrylonitrile (PAN) 3D Architectures with Anchored Lattice-Expanded λ-MnO2 Nanodots as Freestanding Adsorbents for Superior Lithium Separation

Formation of garnet-type Li7La3Zr2O12 nanoparticles as an alternative structural stabilization route

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Atomistic Simulation and Characterization of Spinel Li_1+xMn₂O₄ (0 ≤ x ≤ 1) Nanoparticles

From Atoms to Cells: Multiscale Modeling of LiNi_xMn_yCo_zO₂ Cathodes for Li-Ion Batteries

From Atoms to Cells: Multiscale Modeling of LiNi_xMn_yCo_zO₂ Cathodes for Li-Ion Batteries

Hierarchically Porous Polyacrylonitrile (PAN) 3D Architectures with Anchored Lattice-Expanded λ-MnO₂ Nanodots as Freestanding Adsorbents for Superior Lithium Separation