Lithium‐Oxygen Chemistry at Well‐Designed Model Interface Probed by In Situ Spectroscopy Coupled with Theoretical Calculations

Abstract

The aprotic lithium‐oxygen (Li‐O2) battery has an extremely high theoretical specific energy and potentially provides a tantalizing solution to the renewable energy storage challenge encountered by contemporary and future societies. Nevertheless, the realization of practical Li‐O2 batteries currently meets with substantial challenges that include, but are not limited to, low energy capability and short longevity. To address these obstacles, unveiling the reaction processes and degradation mechanisms of Li‐O2 batteries is crucially important. Over recent years, the research paradigm of in situ spectroscopy coupled with theoretical calculations performed on well‐designed model interfaces, has proved to be indispensable for the fundamental study and performance optimization of various energy storage devices. In this contribution, first representative illustrations of this research paradigm are offered in the study of both primary and parasitic reactions of Li‐O2 batteries, which significantly simplifies, but not degrade, the complex reaction conditions and decouples multiple processes occurring simultaneously in Li‐O2 cells. Then, the perspective is provided on the remaining issues as well as uncertainties and discuss future research directions. Finally, wider research community is encouraged to tailor‐design versatile model interfaces to better bridge in situ spectroscopy and theoretical calculations for the research and development of better Li‐O2 batteries and beyond.

Unlock CO2 Reduction Reaction Pathways in Aprotic Li-CO2 Batteries with In Situ Isotope-Labeled Spectroscopy and Theoretical Calculations

“…Considering the intricate nature of composite cathodes (e.g., binders, conductive carbons with defects or functional groups, electrocatalysts) in practical Li-CO 2 batteries, a simple Au model electrode is selected to investigate CO 2 RR pathways in DMSO-based electrolytes, commonly employed in Li–air batteries . Notably, the Au model electrode has been established as an excellent substrate for in situ vibrational spectroscopy techniques, , including SERS and attenuated total reflectance surface-enhanced infrared absorption spectroscopy (ATR-SEIRAS). These techniques can efficiently enhance the interfacial signal with single-molecule sensitivity and provide a suitable platform to probe the trace intermediates and products involved in the CO 2 RR pathways in aprotic Li-CO 2 batteries.…”

Enhanced Redox Electrocatalysis in High-Entropy Perovskite Fluorides by Tailoring d–p Hybridization

“…7 a) and Raman patterns (Fig. 7 b) reveal the formation of Li 2 CO 3 , LiOH, LiAc, and LiRCO 3 as main side-products on KCoF 3 , KCoMnNiF 3 , KCoMnNiMgF 3 and KCoMnNiZnF 3 cathode [ 31 , 32 ]. In striking contrast, no signal peak assigned to those byproducts emerges on KCoMnNiMgZnF 3 -HEC cathode, even after 500th cycles, unveiling the suppression effect of multiple active sites in HEC on side reactions.…”

Tailoring Li–CO2 Electrochemistry Based on 4,4′-Bipyridine Redox Cycle

“…To understand the BPD-assisted Li–CO 2 electrochemistry, in situ spectroscopic studies including FT-IR and SERS spectroscopies have been conducted using model electrodes of GC and Au in Ar- and CO 2 -saturated 0.1 M LiClO 4 -DMSO electrolytes containing 20 mM BPD, respectively (Figure ). Because of the specific adsorption of BPD on an Au electrode, it is possible to probe the interaction of BPD and CO 2 by monitoring the variation of the SERS spectra of BPD upon introduction of CO 2 (Figure S2).…”