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

Electrolytes are characterized by their ionic conductivity (σ(i)). It is desirable that overall σ(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 σ(i) leading to inferior cell performances. Here we present an organogel polymer electrolyte characterized by a high liquid-electrolyte-level σ(i) (~10(1) 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, σ(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.