Lithium Nitrate Regulated Sulfone Electrolytes for Lithium Metal Batteries

Abstract

The electrolytes in lithium metal batteries have to be compatible with both lithium metal anodes and high voltage cathodes,a nd can be regulated by manipulating the solvation structure.H erein, to enhance the electrolyte stability,l ithium nitrate (LiNO 3)a nd 1,1,2,2-tetrafuoroethyl-2',2',2'trifuoroethyl(HFE) are introduced into the high-concentration sulfolane electrolyte to suppress Li dendrite growth and achieve ah igh Coulombic efficiency of > 99 %f or both the Li anode and LiNi 0.8 Mn 0.1 Co 0.1 O 2 (NMC811) cathodes.M olecular dynamics simulations showt hat NO 3 À participates in the solvation sheath of lithium ions enabling more bis(trifluoromethanesulfonyl)imide anion (TFSI À)t oc oordinate with Li + ions.T herefore,ar obust LiN x O y À LiF-richs olid electrolyte interface (SEI) is formed on the Li surface, suppressing Li dendrite growth. The LiNO 3-containing sulfolane electrolyte can also support the highly aggressive Li-Ni 0.8 Mn 0.1 Co 0.1 O 2 (NMC811) cathode,d elivering ad ischarge capacity of 190.4 mAh g À1 at 0.5 Cfor 200 cycles with acapacity retention rate of 99.5 %.

Identifying the Critical Anion–Cation Coordination to Regulate the Electric Double Layer for an Efficient Lithium‐Metal Anode Interface

“…The choose of NO 3 − as the SEI enabler of interest in this work was based on two considerations: Firstly, lithium nitrate (LiNO 3 ) has been widely recognized as an outstanding film‐forming reagent for Li protection in different electrolyte systems. The as‐generated uniform and highly ionic conductive SEI contributes to high‐efficiency Li plating/stripping [17–19] . Additionally, NO 3 − is of high Gutmann donor number (DN, 22), which affords distinct cation solvation structure even in dilute electrolyte [20] .…”

Constructing nitrided interfaces for stabilizing Li metal electrodes in liquid electrolytes

“…By using high-resolution transmission electron microscopy (TEM, Figure 7e) and XPS depth profiling (Figure 7f), they confirmed that N-containing species, such as Li additive. 94 By using molecular dynamics (MD) simulations, they pointed out that the NO 3 − anions in the Li + solvation sheath could promote the coordination of TFSI − anions with Li + (Figure 8e). During battery cycling, these anions in the Li + solvation sheath would be reduced and formed an inorganic SEI.…”

Gradient Solid Electrolyte Interphase and Lithium‐Ion Solvation Regulated by Bisfluoroacetamide for Stable Lithium Metal Batteries

“…Numerous researches have been taken to artificially obtain suitable SEI to achieve the uniform Li + deposition by selecting suitable electrolyte additives [24–30] . Previous studies have been proved that the F‐containing electrolyte additive could help to obtain high CE and long stable cycling performance due to the formation of LiF in the SEI film [31–36] . Because the LiF possesses low Li + diffusion barrier and large band gap (13.6 eV), which could facilitate the fast transportation of Li + and block the electrons from passing through SEI for side reaction with electrolyte.…”