Conjugated Polymer Energy Level Shifts in Lithium-Ion Battery Electrolytes

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• 作者：Charles Kiseok Song ; Brian J. Eckstein ; Teck Lip Dexter Tam ; Lynn Trahey ; Tobin J. Marks
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2014
• 出版时间：November 12, 2014
• 年：2014
• 卷：6
• 期：21
• 页码：19347-19354
• 全文大小：415K
• ISSN：1944-8252

文摘

The ionization potentials (IPs) and electron affinities (EAs) of widely used conjugated polymers are evaluated by cyclic voltammetry (CV) in conventional electrochemical and lithium-ion battery media, and also by ultraviolet photoelectron spectroscopy (UPS) in vacuo. By comparing the data obtained in the different systems, it is found that the IPs of the conjugated polymer films determined by conventional CV (IP_C) can be correlated with UPS-measured HOMO energy levels (E_H,UPS) by the relationship E_H,UPS = (1.14 卤 0.23) 脳 qIP_C + (4.62 卤 0.10) eV, where q is the electron charge. It is also found that the EAs of the conjugated polymer films measured via CV in conventional (EA_C) and Li⁺ battery (EA_B) media can be linearly correlated by the relationship EA_B = (1.07 卤 0.13) 脳 EA_C + (2.84 卤 0.22) V. The slopes and intercepts of these equations can be correlated with the dielectric constants of the polymer film environments and the redox potentials of the reference electrodes, as modified by the surrounding electrolyte, respectively.

Keywords:

lithium-ion battery; conjugated polymer; electron affinity; cyclic voltammetry; electrolyte; organic photovoltaics