A physical organogel electrolyte: Characterized by in situ thermo-irreversible gelation and single-ion-predominent conduction

Electrolytes are characterized by their ionic conductivity (??i). It is desirable that overall ??i results from the dominant contribution of the ions of interest (e.g. Li+ in lithium ion batteries or LIB). However, high values of cationic transference number (t+) achieved by solid or gel electrolytes have resulted in low ??i leading to inferior cell performances. Here we present an organogel polymer electrolyte characterized by a high liquid-electrolyte- level ??i (???101 mS cm-1) with high t+ of Li+ (>0.8) for LIB. A conventional liquid electrolyte in presence of a cyano resin was physically and irreversibly gelated at 60 ??C without any initiators and crosslinkers, showing the behavior of lower critical solution temperature. During gelation, ??i of the electrolyte followed a typical Arrhenius-type temperature dependency, even if its viscosity increased dramatically with temperature. Based on the Li + -driven ion conduction, LIB using the organogel electrolyte delivered significantly enhanced cyclability and thermal stability.open5

Solvate Structures and Computational/Spectroscopic Characterization of Lithium Difluoro(oxalato)borate (LiDFOB) Electrolytes

Lithium difluoro(oxalato)borate (LiDFOB) is a relatively new salt designed for battery electrolyte usage. Limited information is currently available, however, regarding the ionic interactions of this salt (i.e., solvate formation) when it is dissolved in aprotic solvents. Vibrational spectroscopy is a particularly useful tool for identifying these interactions, but only if the vibrational bands can be correctly linked to specific forms of anion coordination. Single crystal structures of LiDFOB solvates have therefore been used to both explore the DFOB-center dot center dot center dot Li+ cation coordination interactions and serve as unambiguous models for the assignment of the Raman vibrational bands. The solvate crystal structures determined indude (monoglyme)(2):LiDFOB, (1,2-diethoxyethane)(3/2):LiDFOB, (acetonitrile)(3):LiDFOB, (acetonitrile)(1):LiDFOB, (dimethyl carbonate)(3/2):LiDFOB, (succinonitrile)(1):LiDFOB, (adiponitrile)(1):LiDFOB, (PMDETA)(1):LiDFOB, (CRYPT-222)(2/3):LiDFOB, and (propylene carbonate)(1):LiDFOB. DFT calculations have been incorporated to provide additional insight into the origin (i.e., vibrational modes) of the Raman vibrational bands to aid in the interpretation of the experimental analysis