Wang, Y;
Feng, M;
Hou, D;
He, R;
Luo, KH;
(2025)
Dynamics and mechanisms of flame spray pyrolysis of LiMn₂O₄ nanoparticles: A reactive molecular dynamics study.
Chemical Engineering Journal
, 513
, Article 163073. 10.1016/j.cej.2025.163073.
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Abstract
LiMn2O4 is a promising cathode material for lithium-ion batteries. In this study, the synthesis of LiMn2O4 nanoparticles via flame spray pyrolysis (FSP) is investigated using reactive force-field (ReaxFF) molecular dynamics simulations. The study provides a detailed atomic-level view of the reaction pathways throughout the FSP process, from precursor droplet evaporation to nucleation and the growth mechanisms of nanoparticles. Based on temperature and oxygen content profiles, the FSP process is divided into four distinct stages: evaporation and initial decomposition, combustion-driven oxidation, nucleation, and particle growth through accretion and agglomeration. In an oxidizing atmosphere, precursor evaporation occurs alongside oxidation reactions, with Li-containing precursors decomposing and diffusing more rapidly than Mn-containing precursors due to Li’s lower atomic mass and valence. At higher combustion temperatures (Tc), Mn-containing species exhibit temperature-dependent reaction pathways, favoring oxidized intermediates such as MnO2 and MnO2H, whereas Li follows a consistent reaction pathway across different Tc values, with Tc primarily affecting the intermediate concentrations. Nucleation is Mn-dominated, with MnxOyHz (x, y, z > 0) frameworks forming and merging preferentially at higher Tc, while Li is passively incorporated into Mn clusters or organic fragments. Early-stage clusters grow by molecular accretion before transitioning to agglomeration, where organic bonds facilitate the formation of soft agglomerates. By the end of the FSP process, nanoparticles containing Li and Mn oxides form, serving as precursors for crystallized LiMn2O4. Iterative oxidative annealing refines these amorphous nanoparticles into Li/Mn oxides, which contain local LiMn2O4 spinel crystallites, consistent with experimental TEM observations.
| Type: | Article |
|---|---|
| Title: | Dynamics and mechanisms of flame spray pyrolysis of LiMn₂O₄ nanoparticles: A reactive molecular dynamics study |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1016/j.cej.2025.163073 |
| Publisher version: | https://doi.org/10.1016/j.cej.2025.163073 |
| Language: | English |
| Additional information: | Copyright © 2025 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). |
| Keywords: | Flame spray pyrolysis, Cathode Materials, Nanoparticles, LiMn2O4, Molecular dynamics simulation |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Mechanical Engineering |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10210159 |
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