Organically modified silica-supported ionogels electrolyte for high temperature lithium-ion batteries

A new solid-state ionogel electrolyte was synthesized using a silane coupling agent (SCA) that can spontaneously form a porous network to confine an ionic liquid electrolyte (ILE). We found that epoxy groups grafted on silica can promote the ionic dissociation of a lithium salt and ionic liquid. The ionogel with the optimal molar ratio (ILE/SCA=0.75) exhibited excellent thermal stability, a wide redox stability window, and ionic conductivity of 1.91x10(-3) S cm(-1) at 30 degrees C, which is higher than that of the pure IL electrolyte. The developed ionogel improved the operating temperature of batteries from room temperature to at least 90 degrees C. Furthermore, the good compatibility of the ionogel with a LiFePO4 cathode and Li4Ti5O12 anode indicates that it can be used as an electrolyte for full battery systems. More importantly, the SCA was employed as an organosilica precursor to synthesize a new solid-state ionogel electrolyte. This new ionogel electrolyte with high stability and capacity represents a considerable advance in solid-state electrolytes for lithium-ion batteries.