Nanoporous hybrid electrolytes

Abstract

Oligomer-suspended SiO₂–polyethylene glycol nanoparticles are studied as porous media electrolytes. At SiO₂ volume fractions, ϕ, bracketing a critical value ϕ_y ≈ 0.29, the suspensions jam and their mechanical modulus increase by more than seven orders. For ϕ>ϕ_y, the mean pore diameter is close to the anion size, yet the ionic conductivity remains surprisingly high and can be understood, at all ϕ, using a simple effective medium model proposed by Maxwell. SiO₂–polyethylene glycol hybrid electrolytes are also reported to manifest attractive electrochemical stability windows (0.3–6.3 V) and to reach a steady-state interfacial impedance when in contact with metallic lithium.