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Experimental Studies on Work Functions of Li + Ions and Electrons in the Battery Electrode Material LiCoO 2 : A Thermodynamic Cycle Combining Ionic and Electronic Structure
Author(s) -
Schuld Stephan,
Hausbrand René,
Fingerle Mathias,
Jaegermann Wolfram,
Weitzel KarlMichael
Publication year - 2018
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.201703411
Subject(s) - work function , thermionic emission , materials science , battery (electricity) , ionic bonding , x ray photoelectron spectroscopy , cathode , ion , work (physics) , electrode , electron , atomic physics , electronic structure , analytical chemistry (journal) , chemistry , thermodynamics , nanotechnology , condensed matter physics , nuclear magnetic resonance , physics , power (physics) , organic chemistry , layer (electronics) , quantum mechanics , chromatography
The release of Li + from stoichiometric LiCoO 2 (LCO) – a typical battery electrode material – is investigated by means of thermionic emission. Analysis of the data leads to an ionic work function of w Li+ (LCO) = 4.1 eV. Combination of this value with the electronic work function w e− (LCO) = 5.1 eV, also measured in this work by photoelectron spectroscopy, and with information available from the literature allows the set up, for the first time, of a complete thermodynamic cycle for a Li//LiCoO 2 battery. An open circuit cell voltage of 2.4 eV is derived 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 LiCoO 2 as a battery cathode and is expected to open access to a better understanding and thus to a better design of battery materials.