电极
电解质
材料科学
密度泛函理论
偶极子
电压
电化学
薄膜
电池(电)
电子
锂(药物)
钝化
光电子学
化学物理
分析化学(期刊)
纳米技术
图层(电子)
化学
电气工程
计算化学
物理化学
物理
热力学
医学
功率(物理)
量子力学
有机化学
色谱法
内分泌学
工程类
作者
Kevin Leung,Andrew J. Leenheer
出处
期刊:Cornell University - arXiv
日期:2015-01-01
标识
DOI:10.48550/arxiv.1507.02334
摘要
Battery electrode surfaces are generally coated with electronically insulating solid films of thickness 1-50 nm. Both electrons and Li+ can move at the electrode-surface film interface in response to the voltage, which adds complexity to the "electric double layer" (EDL). We apply Density Functional Theory (DFT) to investigate how the applied voltage is manifested as changes in the EDL at atomic lengthscales, including charge separation and interfacial dipole moments. Illustrating examples include Li(3)PO(4), Li(2)CO(3), and Li(x)Mn(2)O(4) thin-films on Au(111) surfaces under ultrahigh vacuum conditions. Adsorbed organic solvent molecules can strongly reduce voltages predicted in vacuum. We propose that manipulating surface dipoles, seldom discussed in battery studies, may be a viable strategy to improve electrode passivation. We also distinguish the computed potential governing electrons, which is the actual or instantaneous voltage, and the "lithium cohesive energy" based voltage governing Li content widely reported in DFT calculations, which is a slower-responding self-consistency criterion at interfaces. This distinction is critical for a comprehensive description of electrochemical activities on electrode surfaces, including Li+ insertion dynamics, parasitic electrolyte decomposition, and electrodeposition at overpotentials.
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