Battery performance strongly depends on the choice of the electrolyte-solvent system. Lithium bis(fluorosulfonyl)imide (LiFSI) is a highly interesting novel electrolyte. Information on physico-chemical properties of solutions of LiFSI, however, is scarce. Therefore, the density, shear viscosity, and electrical conductivity of solutions of LiFSI in three pure solvents that are interesting for battery applications: dimethyl carbonate (DMC), ethylene carbonate (EC), and propylene carbonate (PC), were studied experimentally at temperatures between 273 K and 333 K at 1 bar and concentrations of LiFSI up to 0.45 mol mol −1 in the present work. Empirical correlations of the experimental data are provided.The comparison of the data of this work with the corresponding LiPF 6 data underpins the attractiveness of LiFSI as an electrolyte in lithium ion batteries.

Organic solutions of lithium bis(fluorosulfonyl)imide (LiFSI) are promising electrolytes for Li‐ion batteries. Information on the diffusion coefficients of the species in these solutions is needed for battery design. Therefore, the self‐diffusion coefficients in such solutions were studied experimentally with the pulsed‐field gradient nuclear magnetic resonance technique. The self‐diffusion coefficients of the ions Li+ and FSI− as well as those of the solvents were measured for LiFSI solutions in pure dimethyl carbonate and ethylene carbonate as well as in mixtures of these solvents at 298 K and ambient pressure. Despite the Li+ ion being the smallest species in the solution, its self‐diffusion coefficient is the lowest as a result of its strong coordination with the solvent molecules.

Lithium bis(fluorosulfonyl)imide (LiFSI) is an interesting novel electrolyte for lithium-ion batteries. In the present work, the electrical conductivity of solutions of LiFSI in binary and ternary mixtures of the solvents dimethyl carbonate (DMC), ethylene carbonate (EC) and propylene carbonate (PC) was studied experimentally for concentrations of LiFSI up to 0.2 mol mol −1 at ambient pressure and temperatures between 293 and 333 K. Information on the electrical conductivity of LiFSI in the pure solvents DMC, EC, and PC is available from previous work. An empirical correlation of the electrical conductivity σ of the studied solutions of LiFSI is presented that describes the dependence of σ on the LiFSI concentration, the solvent composition, and the temperature. Based on this correlation, a multi-objective optimization of the LiFSI concentration and the solvent composition was carried out with two conflicting objectives relevant to the performance and costs of batteries: maximizing electrical conductivity and minimizing the amount of the expensive electrolyte LiFSI. The solubility limits of the ternary solvent system DMC-EC-PC were included in the optimization as

Lithium bis(fluorosulfonyl)imide (LiFSI) is an interesting electrolyte for lithium ion batteries and valeronitrile is a good solvent for LiFSI as it forms complexes with the Li + -ions. In the present work, this complexation was studied by optical spectroscopy (Raman and IR), as well as by nuclear magnetic resonance (NMR) spectroscopy. Based on the spectroscopic information a chemical model for the complexation was developed and the equilibrium constants for the formation of the different species that were considered are reported.

Lithium bis­(fluorosulfonyl)­imide (LiFSI) is a novel electrolyte for lithium-ion batteries. Valeronitrile (VN) is a good solvent for LiFSI, and dichloromethane (DCM), 1,2-dichloroethane (DCE), and 1,2-dichlorobenzene (DCB), are interesting antisolvents for crystallization. Physico-chemical data for the design of LiFSI production processes, in which these components are used, is lacking. Therefore, the solubility of LiFSI in VN, as well as in binary solvent mixtures VN + (DCM, DCE, DCB) was measured at temperatures between 278 and 343 K and concentrations of LiFSI up to 0.52 mol mol–1. Furthermore, vapor–liquid equilibria of the systems VN–DCE (at 200 mbar) and VN–DCB (at 200, 300, and 450 mbar) were studied. Also, the density and shear viscosity of solutions of LiFSI in VN were measured at temperatures between 293 and 333 K and concentrations of LiFSI up to 0.5 mol mol–1.