Ca2+ Solvation and Electrochemical Solid/Electrolyte Interphase Formation Toward the Multivalent-Ion Batteries
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Yang, Feipeng↗
Engineering topics
Glans, Per-Anders
Publications and source records attributed to Glans, Per-Anders.
Electronic surface reconstruction of TiO 2 nanocrystals revealed by resonant inelastic x-ray scattering
The identification of lattice multiphases in TiO 2 nanocrystals is studied by high resolution transmission electron microscope and electron diffraction patterns. Based on the spectroscopic analysis using soft x-ray absorption and resonant inelastic soft x-ray scattering, it is believed that the oxygen vacancies at the interface exhibit structural distortion of the TiO$^{8-}_6$ cluster around the defect site as for the multiphase lattice. We elucidate that the extra 3d electrons nearby induce the inelastic scattering features with the excitation energy dependence owing to different energy relaxation processes, a characteristic of the electron-phonon coupling or the nature of the electron-hole pair at the intermediate state. The manifold dd excitations driven by the strong interaction between Ti-3d and O-2p electrons are noticeably rich, coexisting on both Ti and O sites. Finally, this sophisticated experiment can advance the perspective of nanocomposite TiO 2 for various interactions of surface Ti 3+ in applications of future devices.
36 MATERIALS SCIENCE↗
In situ/operando soft x-ray spectroscopy of chemical interfaces in gas and liquid environments
Many energy storage and energy conversion systems are based on the complexity of material architecture, chemistry, and interfacial interactions. To understand and thus ultimately control the energy applications calls for in situ/operando characterization tools. Over the years, in situ/operando soft x-ray spectroscopy has been developed for the studies of gas molecules, molecular liquids, catalytic, and electrochemical reactions. Soft x-ray spectroscopy offers electronic structure characterization of materials in energy conversion, energy storage, and catalysis regarding functionality, complexity of material architecture, and chemical interactions. It has been shown how to use the powerful in situ/operando soft x-ray spectroscopy characterization techniques of interfacial phenomena and how to reveal the mechanism of charge transfer and chemical transformation of solid/gas and solid/liquid interfaces of energy storage and catalytic materials in a realistic environment. It has been demonstrated how to overcome the challenge that soft x-rays cannot easily peek into the high-pressure catalytic or liquid electrochemical reactions. Finally, the unique design of in situ/operando soft x-ray spectroscopy instrumentation and fabrication principle and examples of experiments are presented.
36 MATERIALS SCIENCE↗
MoS 2 for beyond lithium-ion batteries
As a typical transition-metal chalcogenide material, molybdenum disulfide (MoS 2 ) has received tremendous attention because of its unique layered structure and versatile chemical, electronic, and optical properties. With the focus of this Perspective on the energy storage area, one of the most important contributions of MoS 2 is that it sparked the birth of the rechargeable lithium battery in the early 1980s, which later formed the foundation of commercial lithium batteries. After four decades, admitting that MoS 2 is still playing a significant role in the lithium-ion battery field and considerable effort was made to decipher the mechanism through ex situ and in situ studies and by means of MoS 2 nanostructure engineering that advances the lithium battery performance, it is also used in beyond lithium-ion batteries, such as sodium, magnesium, calcium, and aluminum energy storage systems. Such alternative battery systems are desirable because of the safety concerns of lithium and the depletion of lithium reserves and corresponding increase in cost. In this Perspective, recent development on the fabrication of novel MoS 2 nanostructures was discussed, followed by the scrutinization of their application in beyond lithium-ion batteries and the in situ/operando methods involved in these studies. Finally, a brief summary and outlook that may help with the future advancement of the beyond lithium-ion batteries are presented.
25 ENERGY STORAGE↗