The electrochemical double layer and its impedance behavior in lithium-ion batteries

Abstract

Interfacial reaction and transport processes contribute crucially to the overall performance and impedance of electrochemical systems. The influence of the electrochemical double layer and the interfacial reactions on the impedance of lithium intercalation batteries is investigated with a modeling approach. Our generic theory for charge and electron transfer reactions at electrified interfaces and its simplified adaptation, a reduced interface model, are compared with the standard for electrochemical interface modeling, the Butler–Volmer ansatz, in terms of numerically simulated impedance spectra. Both of our interface models inherently provide significant impedance characteristics that go beyond the standard approach due to their theoretically consistent derivation. We discuss resistant and capacitive contributions of the double layer to impedance spectra and analyze the effect of strongly correlated interfacial dynamics.