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LEC Events/Seminars
Die Seminare finden im Raum ODRA/111 jeweils am Mittwoch um 11:00 Uhr statt. Externe Gäste (ausserhalb des PSI) sind willkommen, werden aber gebeten, sich im Labor-Sekretariat bei Frau Cordelia Gloor unter Tel.: +41 56 310 2919 oder per e-mail anzumelden. Lectures take place in room ODRA/111 on every Wednesday at 11:00 am. External guests (from outside PSI) are welcome, but are requested to register with our secretary Cordelia Gloor at phone: +41 56 310 2919 or via e-mail.
Reactivity and potential profile across the electrified LiCoO2-Li3PS4 interface probed by operando X-ray photoelectron spectroscopy
All-solid-state lithium batteries are a promising alternative for next generation of safe energy storage devices, provided that parasitic side reactions and the resulting hindrances in ionic transport at the electrolyte-electrode interface can be overcome. Motivated by the need for a fundamental understanding of such interface, we present here real-time measurements of the (electro-)chemical reactivity and local surface potential at the electrified interface Li3PS4 and LiCoO2 using operando X-ray photoelectron spectroscopy.
Li-ion solvation in TFSI and FSI - based ionic liquid electrolytes probed by X-ray photoelectron spectroscopy
We demonstrate the capability of conventional laboratory XPS to determine the anions solvation shell of Li+ cation within 1M of LiTFSI and 1M of LiFSI salts dissolved in (EMIM+-FSI-) and (EMIM+-TFSI-) ionic liquids. The binding energy difference between the N1s components originating from the EMIM+ cation and from TFSI- or FSI- anions, solvating the Li+, confirms that both TFSI- and FSI- contribute simultaneously to the Li+ solvation. Additionally, the degradation of the TFSI and FSI -based electrolytes under X-ray exposure is proved.
Integration of Li4Ti5O12 crystalline films on silicon towards high-rate performance lithionic devices
The growth of crystalline Li-based oxide thin films on silicon substrates is essential for the integration of next-generation solid-state lithionic and electronic devices. In this work, we employ a 2 nm γ-Al2O3 buffer layer on Si substrates in order to grow high quality crystalline thin films Li4Ti5O12 (LTO). Long-term galvanostatic cycling of 50 nm LTO demonstrates exceptional electrochemical performance, specific capacity of 175 mAh g-1 and 56 mAh g-1 at 100C and 5000C respectively, with a capacity retention of 91% after 5000 cycles.
Understanding the (de-)lithiation mechanism of nano-sized LiMn2O4 allows achieving long-term cycling stability
We report an in-depth investigation of the local atomic geometry, electronic and crystallographic structure evolution of nano-sized LiMn2O4 using operando XAS and XRD to shed light on (de-)lithiation mechanism when cycled in wide voltage range of 2.0 to 4.3 V vs Li+/Li. Leveraging on these findings, a novel electrochemical cycling protocol, with periodic deep discharge, yields superior electrochemical performance cycled in the range of 3.3 to 4.3 V exhibiting an excellent structure cyclability and an unprecedented increase in the specific capacity upon long cycling.
Publications 2014
Electrochemistry Laboratory (LEC)