Recherche

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.

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.   

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.

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.