Computational determination of the solvation structure of LiBF4 and LiPF6 salts in battery electrolytes
Computational determination of the solvation structure of LiBF4 and LiPF6 salts in battery electrolytes
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DOI：
10.1016/j.colsurfa.2023.131831
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发表时间：
2023-10
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影响因子：
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通讯作者：
M. Peiris;Scott Brennan;Diana Liepinya;Hao Liu;Manuel Smeu
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作者：
M. Peiris;Scott Brennan;Diana Liepinya;Hao Liu;Manuel Smeu
锂离子电池技术自几十年前最初发展以来已经走过了漫长的道路。然而，对储能的期望不断增长，使得电池技术的优化至关重要。沿着电极电化学性能的提高，对电解质性能的研究也变得十分必要。在这项工作中，我们使用第一性原理计算模型来调查的结构和物理相互作用的一个共同的溶剂解决方案，碳酸亚乙酯：碳酸二甲酯，与两种盐，LiP F 6和LiB F 4。我们看看溶剂化壳层的形成和发展使用从头算分子动力学（AIMD）模拟。从计算轨迹提取的溶剂化结构被用来调查使用密度泛函理论（DFT）的能量去除个别溶剂分子。我们还研究了溶剂分子在盐周围形成壳层的顺序。LiB F 4和LiP F 6具有相似的溶剂化结构和与溶剂的相互作用能，优选羰基氧和醚氧与Li+阳离子相互作用，甲基或亚甲基与B F 4−或P F 6−阴离子相互作用。我们的计算还发现，与LiB F 4相比，LiP F 6周围形成的溶剂化壳更容易去溶剂化，这表明动力学/扩散更容易。
Li-ion battery technology has come a long way since its initial development a few decades ago. However, expectations of energy storage continue to grow, making the optimization of battery technology vital. Along with improving the electrochemical performance of electrodes, investigation of the properties of the electrolyte has thus become necessary. In this work, we use first principles computational modeling to investigate the structural and physical interactions of a common solvent solution, ethylene carbonate: dimethyl carbonate, with two salts, LiP F 6 and LiB F 4. We look at how the solvation shells form and evolve using ab initio molecular dynamics (AIMD) simulations. The solvation structures extracted from the calculated trajectories are used to investigate the energetics of removal of individual solvent molecules using density functional theory (DFT). We also investigate the order in which the solvent molecules form a shell around the salts. LiB F 4 and LiP F 6 have similar solvation structures and interaction energies with the solvent, with a preference for the carbonyl oxygens and the ether oxygens to interact with the Li+ cations, and the methyl or methylene groups to interact with the B F 4− or P F 6− anions. Our calculations also find that the solvation shell formed around LiP F 6 can desolvate more easily compared to LiB F 4, suggesting easier kinetics/diffusion.