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 1.91×10⁻³ S cm⁻¹ at 30 °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 °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.