Dresden 2020 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 37: Interfaces and Thin Films II (joint session CPP/DY/O)
CPP 37.7: Talk
Tuesday, March 17, 2020, 11:30–11:45, ZEU 260
Insight into ion transport across polypyrrole-electrolyte interfaces by in situ X-ray reflectivity and electrochemistry — •Pirmin H. Lakner1,2, Manuel Brinker3, Christoph Seitz1, Sergey Volkov1, Patrick Huber3, and Thomas F. Keller1,2 — 1Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany — 2Physics Department, Universität Hamburg, Germany — 3Institute of Materials Physics and Technology, Technische Universität Hamburg-Harburg, Germany
Polypyrrole (PPy) is a conducting polymer with actuatoric and pseudocapacitive properties due to potential-induced ion incorporation/expulsion. Electrical potentials were applied to a perchlorate-doped PPy thin film (∼30 nm) in an aqueous perchloric acid electrolyte and the associated changes in thickness and electron density were recorded by X-ray reflectivity (XRR). Assuming a sole perchlorate anion transfer carrying 50 electrons, a ratio of 50:1 is expected between electrons crossing the PPy-substrate interface and electrons crossing the electrolyte-PPy interface. By correlating the XRR data and the electrochemical data, a ratio of 10:1 was obtained, which indicates that water movement takes place as an anion counter-flow. The recorded low strain-charge coefficient supports this assumption. One explanation is the high stability and the low porosity of the PPy film due to its fast potentiodynamic deposition method. The properties of the analyzed PPy film make it a suitable choice for supercapacitor applications.