Electrophilically Trapping Water for Preventing Polymerization of Cyclic Ether Towards Low‐Temperature Li Metal Battery

Abstract

Cyclic ether, such as 1,3-dioxolane (DOL), are promising solvent for low-temperature electrolytes because of the low freezing point. Their use in electrolytes, however, is severely limited since it easily polymerizes in the presence of lithium inorganic salts. The trace water plays a key role via providing the source (proton) for chain initiation, which has, unfortunately, been neglected in most cases. In this work, we present an electrophile, trimethylsilyl isocyanate (SiÀ NCO), as the water scavenger, which eliminates moisture by a nucleophilic addition reaction. SiÀ NCO allows DOL to maintain liquid over a wide temperature range even in highconcentration electrolyte. Electrolyte with SiÀ NCO additive shows promising low-temperature performance. Our finding expands the use of cyclic ether solvents in the presence of inorganic salts and highlights a large space for unexplored design of water scavenger with electrophilic feature for low-temperature electrolytes.

A eutectic electrolyte for an ultralong-lived Zn//V2O5cell: anin situgenerated gradient solid-electrolyte interphase

“…The organic components were mainly derived from the decomposition of DME, which is attributed to the protic acid produced by BF 4 − hydrolysis attacking the O containing lone pair electrons in the DME molecules. 56,57 First principles calculation showed that BF 4 − and DME had higher adsorption energy with different crystal planes of Zn compared to H 2 O, facilitating the formation of passivation layers rather than the HER (Fig. S7, ESI†).…”

Prussian White Cathode Materials for All-Climate Sodium-Ion Batteries

“…We found that the introduction of an anion receptor additive (TTFEB) into cyclic ether DOL effectively restrained its polymerization by capturing the PF 6 – anion . Given that trace water plays a crucial role by providing a source (protons) of chain initiation, we demonstrated a novel way to prevent polymerization by removing protonic acid through the nucleophilic addition reaction of water scavenger (Si–NCO) (Figure a). Si–NCO shows high water removal efficiency thanks to the strong electrophilic center induced by the electron-withdrawing conjugation effect.…”

“…(a) Schematic representation of the design principle of a water scavenger to prevent DOL-based electrolyte gelation. Reprinted with permission from ref . Copyright 2023 Wiley-VCH.…”

Locally Concentrated Ionic Liquid Electrolytes Enabling Low‐Temperature Lithium Metal Batteries

“…[9][10][11] Electrolyte engineering is one of the most relevant strategies in developing low-temperature, dendrite-free, and highly reversible LMAs, because electrolytes not only govern the Li + transport and de-solvation, but also affect the formation of the SEIs. [12,13] So far, a few electrolytes based on liquefied gas, [14,15] ether, [7,16] carbonate, [17,18] and/or acetate solvents with low freezing points have been reported for such a purpose. [19,20] It has also become clear that the solvation structure of Li + has significant influence on the low-temperature performance of LMAs.…”