Lithium Salt Dissociation Promoted by 18‐Crown‐6 Ether Additive toward Dilute Electrolytes for High Performance Lithium Oxygen Batteries

Abstract

Lithium-oxygen batteries (LOBs) are well known for their high energy density. However, their reversibility and rate performance are challenged due to the sluggish oxygen reduction/evolution reactions (ORR/OER) kinetics, serious side reactions and uncontrollable Li dendrite growth. The electrolyte plays a key role in transport of Li + and reactive oxygen species in LOBs. Here, we tailored a dilute electrolyte by screening suitable crown ether additives to promote lithium salt dissociation and Li + solvation through electrostatic interaction. The electrolyte containing 100 mM 18crown-6 ether (100-18C6) exhibits enhanced electrochemical stability and triggers a solution-mediated Li 2 O 2 growth pathway in LOBs, showing high discharge capacity of 10 828.8 mAh g carbon À 1 . Moreover, optimized electrode/electrolyte interfaces promote ORR/OER kinetics on cathode and achieve dendrite-free Li anode, which enhances the cycle life. This work casts new lights on the design of low-cost dilute electrolytes for high performance LOBs.

Bifunctional Dynamic Adaptive Interphase Reconfiguration for Zinc Deposition Modulation and Side Reaction Suppression in Aqueous Zinc Ion Batteries

“…Consistent with this observation, an optical microscope showed many bubbles (Figure S20) at this potential. The large amount of H 2 produced not only damages the battery’s performances but also raises concerns about its safety . However, in Cl-GQD-based electrolytes, the Zn//LMO cells displayed a significantly reduced HER at only 3.4 nmol min –1 (Figure d).…”

“…The large amount of H 2 produced not only damages the battery's performances but also raises concerns about its safety. 55 However, in Cl-GQD-based electrolytes, the Zn//LMO cells displayed a significantly reduced HER at only 3.4 nmol min −1 (Figure 5d). These results suggest that the dynamic adaptive interphase successfully mitigated the corrosion of the Zn anode by active water molecules throughout the plating/stripping process, which was further confirmed by electrochemical impedance spectroscopy (EIS) and ex situ SEM images.…”

Influence of Functional Groups on Li-Ion Transport in Dual-Ion vs Single-Ion Conducting Comb-Branched Polymer Electrolytes

“…The same trend is present for SIC-X and short-SIC-X electrolytes, confirming that ether is the most efficient functional group for screening the strong electrostatic interaction between Li + and TFSI, which is consistent with previous studies. 45,46 EC electrolytes have the next highest probability of isolated Li + . Both ether and EC display relatively narrow distributions.…”

Dendrite‐Free Lithium Metal Batteries Enabled by Coordination Chemistry in Polymer‐Ceramic Modified Separators

“…With the improved understanding of the lithium dendrite growth mechanism, various novel protection strategies have been developed to construct stable lithium anodes. These typically include: i) optimizing electrolyte composition by adding additives, [13,14] utilizing different solvents to optimize lithium salt concentrations, [15,16] and employing solid-state electrolytes. [17,18] Unfortunately, the solvents or additives used to modify the properties of the electrolyte often come at a higher cost and involve intricate fabrication steps, or may also be consumed and depleted during repetitive cycling of the battery.…”