A Stable Lithium–Oxygen Battery Electrolyte Based on Fully Methylated Cyclic Ether

Abstract

Ether-based electrolytes are commonly used in Li-O 2 batteries (LOBs) because of their relatively high stability.But they are still prone to be attacked by superoxides or singlet oxygen via hydrogen abstract reactions,w hich leads to performance decaying during long-term operation. Herein we propose am ethylated cyclic ether,2 ,2,4,4,5,5-hexamethyl-1,3dioxolane (HMD), as as table electrolyte solvent for LOBs. Such acompound does not contain any hydrogen atoms on the alpha-carbon of the ether,a nd thus avoids hydrogen abstraction reactions.A st he result, this solvent exhibits excellent stability with the presence of superoxideo rs inglet oxygen. In addition the CO 2 evolution during charge process is prohibited. The LOB with HMD-based electrolyte was able to run up to 157 cycles,4times more than with 1,3-dioxolane (DOL) or 1,2dimethoxyethane (DME) based electrolytes.Lithium-oxygen battery (LOB) has inspired much enthusiasm from researchers because of its high theoretical energy density. [1] However,s ome problems,s uch as low round-trip efficiency, [2] poor reversibility, [3] and inferior electrolyte stability hinder its practical application. [4] At ypical nonaqueous Li-O 2 battery stores/releases energy with the reversible electrochemical reaction between Li + and O 2 .D uring this process,some oxidizing intermediates,such as LiO 2 ,O 2 2ÀSupportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.

Material balance in the O2 electrode of Li–O2 cells with a porous carbon electrode and TEGDME-based electrolytes

“…Besides the decomposition mechanism proposed for monoglyme, 40,42,43 we would like to point out that formate esters (9) might be produced by the cOH radical initiated oxidation of 1 92 0 8 8 73 7 8 4 3 83 7 10 17 58 9 vinyl ethers (6), 44 where cOH radicals can be generated by singlet oxygen and water. 45 The degradation reactions of the aldehydes (7) leading to formic/acetic acids (or formate/acetate) are complex to describe.…”

Overlooked Factors Required for Electrolyte Solvents in Li–O2 Batteries: Capabilities of Quenching 1O2 and Forming Highly‐Decomposable Li2O2

“…The authors of numerous previous studies have specifically focused on tolerance against superoxide radicals (O 2 À ). [5][6][7][8] A typical strategy is to design electrolyte molecules such that hydrogen abstraction cannot occur. [9] However, recent studies have pointed out that singlet oxygen ( 1 O 2 ) generated during discharge-charge cycles could be among the species responsible for decomposing the electrolyte and electrodes.…”

“…To address the former problem, an electrolyte with high chemical stability is needed. The authors of numerous previous studies have specifically focused on tolerance against superoxide radicals (O 2 − ) [5–8] . A typical strategy is to design electrolyte molecules such that hydrogen abstraction cannot occur [9] .…”

A Liquid/Liquid Electrolyte Interface that Inhibits Corrosion and Dendrite Growth of Lithium in Lithium‐Metal Batteries

“…[2] Unfortunately,Limetal is thermodynamically unstable towards the polar electrolyte components (solvent, polysulfide,a dditives), which causes extremely unwanted side reaction and uncontrolled Li dendrite growth during cycling. [3] Theu nstable and repeated Li plating/ stripping also results in Li loss from anode.T he above-mentioned characteristics initiates the low Coulombic efficiency and safety issue of LMBs.…”