IMO-IMOMEC researchers develop new class of solid composite electrolytes for Li-ion batteries: Eutectogels Mar 22, 2018
IMO-IMOMEC researchers at Hasselt University/Energyville in Belgium are proposing a new class of solid composite electrolytes (SCEs) for Li-ion batteries: deep eutectic solvent (DES)–silica composites. The DES-based gel electrolytes—to which the team refers as eutectogels (ETGs)—are characterized by high ionic conductivity (1.46 mS cm–1), thermal (up to 130 °C) and electrochemical stability (up to 4.8 V), and are chemically inert to solvents and water.
These ETGs can be easily processed—potentially at lower costs—than ionic-liquid-based composite electrolytes. In a paper in the ACS journal Chemistry of Materials, the team reports that the good prospects of ETGs for application in Li/Li-ion batteries are demonstrated by stable cycling of Li/ETG/LiFePO4 cells over 100 cycles at C/10.
The Li+-conducting deep eutectic solvent (DES) is a blend of n-methylacetamide (NMAC) and bis(trifluoromethane)sulfonimide lithium salt (LiTFSI). Recent investigations of DES suggest an optimal molar ratio of LiTFSI:NMAC = 1:4 for applications in Li-ion batteries and capacitors.
Using the same composition, the team confined DES within a silica matrix via a nonaqueous sol-gel route. The resulting ETGs are transparent, homogeneous, glass-like monoliths without cracks. Cross-sections of the ETGs showed a porous structure filled with DES.
link to Green Car Congres where the results of the research were presented.