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MM: Fachverband Metall- und Materialphysik
MM 37: Materials for Energy Storage and Conversion - Structure of Battery Materials
MM 37.3: Vortrag
Mittwoch, 18. März 2020, 12:15–12:30, IFW D
Highly stable and highly conductive LiCoPO4 olivine-based thin film 5V cathode material. — •Gennady Cherkashinin1, Robert Eilhardt1, Silvia Nappini2, Igor Píš2, Federica Bondino2, Simone dal Zilio2, Elena Magnano2, Matteo Cococcioni3, and Lambert Alff1 — 1Technische Universität Darmstadt, Germany — 2IOM CNR Laboratorio TASC, Basovizza, TS, Italy — 3Physics Department, University of Pavia, Italy
Recently, we have discovered high electronic conductivity of the LiCoPO4 olivine 5V cathode thin film material tailored with LiCo2P3O10. The crystal structure of the compound remains stable even if all Li-ions leave the olivine structure, which corresponds to ~5.1V vs. Li+/Li. Here we explore the intrinsic stability of the novel thin film cathode material and the stability of cathode/electrolyte interface upon the charging/discharging potential in the 3.0-5.1V range. We apply the comprehensive in-situ electron spectroscopy approach (XPS and XAS) combined with first principle calculations to study the evolution of the oxidation and valence states, the Co3d-O2p hybridization, the work function, the density of occupied and unoccupied states near the Fermi level, the chemical composition, etc. as a function of the Li-content. We show that the electronic structure/properties of the compound are fully reversible; LiCo2P3O10 stabilizes the olivine structure in its fully delithiated state. First-principles simulations predict ~5.2V redox for LiCo2P3O10. Thus, higher energy density via the involvement of LiCo2P3O10 into the redox reaction is possible. A reason of enhanced conductivity at atomic level is analyzed.