Berlin 2018 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 2: Battery Materials
MM 2.1: Vortrag
Montag, 12. März 2018, 10:15–10:30, H 0106
A thermodynamic description of the battery material LiCoO2 based on ionic and electronic work functions — •Johanna Schepp1, Stephan Schuld1, Rene Hausbrand2, Mathias Fingerle2, Wolfram Jägermann2, and Karl-Michael Weitzel1 — 1Philipps Universität Marburg, Chemistry Department — 2TU Darmstadt, Department of Material Science
The release of Li+ from stoichiometric LiCoO2 (LCO) - a typical battery electrode material has been investigated by means of thermionic emission. Analysis of the data leads to an ionic work function of wLi+(LCO) = 4.1 eV. Combination of this value with the electronic work function we-(LCO) = 5.1 eV also measured in this work by photoelectron spectroscopy, and information available from the literature allows to setup for the first time a complete thermodynamic cycle for a LiCoO2 // Li battery. We arrive at an open circuit cell voltage of 2.4 eV in line with available literature information. The proof-of-principle study presented here provides experimental data on the binding energy values, i.e. chemical potentials, of Li+-ions and electrons and thus of Li-atoms in LiCoO2 as battery cathode and is expected to open access to a better understanding and consequently also a better design of battery materials. Current efforts in measuring the long term characteristics of LCO as a function of the composition and the total amount charges exchanged will be discussed.