Solvation Structure with Enhanced Anionic Coordination for Stable Anodes in Lithium‐Oxygen Batteries

Abstract

Li‐O2 batteries have garnered much attention due to their high theoretical energy density. However, the irreversible lithium plating/stripping on the anode limits their performance, which has been paid little attention. Herein, a solvation‐regulated strategy for stable lithium anodes in tetraethylene glycol dimethyl ether (G4) based electrolyte is attempted in Li‐O2 batteries. Trifluoroacetate anions (TFA−) with strong Li+ affinity are incorporated into the lithium bis(fluorosulfonyl)imide (LiTFSI)/G4 electrolyte to attenuate the Li+‐G4 interaction and form anion‐dominant solvates. The bisalt electrolyte with 0.5 M LiTFA and 0.5 M LiTFSI mitigates G4 decomposition and induces an inorganic‐rich solid electrolyte interphase (SEI). This contributes to decreased desolvation energy barrier from 58.20 to 46.31 kJ mol−1, compared with 1.0 M LiTFSI/G4, for facile interfacial Li+ diffusion and high efficiency. It yields extended lifespan of 120 cycles in Li‐O2 battery with a limited Li anode (7 mAh cm−2). This work gains comprehensive insights into rational electrolyte design for Li‐O2 batteries.

Promoted Reaction Reversibility by Dual-Effect 15-Crown-5 Ether Additive for High-Performance Li–O2 Batteries

“…Moreover, the 1 H NMR spectra further prove that the electrolyte with 15C5 has a great stability during cycles (Figure S6). 29 For the CV curve of the battery with DMSO + LiNO 3 + 15C5 under an O 2 atmosphere, stronger reduction and oxidation peaks are observed for the battery in DMSO + LiNO 3 + 15C5 than that in DMSO + LiNO 3 , indicating promoted ORR and OER kinetics induced by the addition of 15C5. At the beginning of the positive sweep, the current in DMSO + LiNO 3 is almost zero, indicating that the active site on the electrode surface has been covered by the reduction products.…”

Advanced Electrolytes for Rechargeable Lithium Metal Batteries with High Safety and Cycling Stability

“…Through the complementary physical and chemical properties, as well as their interaction in the electrolyte, these additives not only enhance the safety and reduce the flammability of lithium electrodes but also improve battery cycle stability, as shown in Figure a. The solvation structure in LEs also exerts a significant influence on the safety and stability of the battery, , which can be fine-tuned by manipulating the concentration of lithium salt and the choice of solvent. The high concentration of salt in the electrolyte alters the solvation structure and physical and chemical properties of LEs by increasing the ratio of lithium salt to solvent, thereby achieving a nonflammable electrolyte .…”