Pseudoconcentrated Electrolyte with High Ionic Conductivity and Stability Enables High-Voltage Lithium-Ion Battery Chemistry

Abstract

Electrolytes play a decisive role in determining the energy density, cycling life, safety, and temperature adaptability of lithium-ion batteries or any advanced battery chemistries. Here a "pseudoconcentrated electrolyte" combining advantages of both concentrated and diluted electrolytes is described as a brandnew approach for high-performance lithium-ion batteries. By designing a heterogeneous liquid structure for an electrolyte, we made it possible for Li + to form a solvation sheath structure that is only attainable in concentrated electrolytes while using a low salt concentration. Such a pseudoconcentrated electrolyte, with lithium bis(trifluoromethanesulfonyl imide) as lithium salt and carbonates as solvents, demonstrates high electrochemical oxidation resistance and a high anticorrosion capability toward an Al current collector, which are usually the characteristics of concentrated electrolytes, as well as high ionic conductivity and low viscosity, which are only available from diluted electrolytes. Thus, this innovative approach provides a brand-new avenue to tailor electrolyte properties for advanced battery chemistry applications.

Analyzing the Mechanism of Functional Groups in Phosphate Additives on the Interface of LiNi0.8Co0.15Al0.05O2 Cathode Materials

“…In order to explain the phenomenon, the conductivity and Raman spectra of the electrolyte with LiDFP were measured. 26 Ionic conductivities of the electrolytes as a function of LiDFP, LiDFBOP, and LTFOP percentages at 25 °C are demonstrated in Figure 3a and Tables S1 and S2. As shown in Figure 3a, the conductivity of STD reduced with the incorporation of LiDFP and further reduced with the increase of LiDFP concentration.…”

Optimizing the composition of LiFSI-based electrolytes by a method combining simplex with normalization

“…The electrochemical stability of the Al collector in the electrolyte can also be tested by the leakage current. 29 Another basic parameter of electrolyte is the enough high ionic conductivity to facilitate the transport of lithium ions, which can be obtained by conductivity meter.…”

Remedies to Avoid Failure Mechanisms of Lithium-Metal Anode in Li-Ion Batteries

“…To avoid such drawbacks, co-solvents can be added [44], such as hydrofluoroethers, since they do not break the solvation structures, thus maintaining the high anodic stability of the electrolytes [45]. The diluent solvent introduced to the HCE to restore the low viscosity forms a so-called "localized high-concentration electrolyte" (LHCE) [46][47][48][49] or "pseudo-concentrated electrolyte" [50,51]. Inert solvent in LHCE means a solvent that does not dissociate the salt or coordinate with the salt cations, so that the merits of the HCEs are retained.…”