Ionic Conductivity and Mechanical Properties of Slide-Ring Gel Swollen with Electrolyte Solution Including Lithium Ions

Polymer gel electrolytes with both high ionic conductivity and mechanical ductility are produced using a slide-ring (SR) gel swollen with an electrolyte solution (ES) composed of propylene carbonate (PC) and lithium salt. The SR gel was derived from polyrotaxane (PR), in which cyclic molecules known as cyclodextrins (CDs) are threaded on the axial polymer chain of polyethylene glycol (PEG) capped by bulky ends, through intermolecular crosslinking between the CDs. The molar conductivity of the SR gel electrolyte with a high swelling ratio and small crosslinking density was more than 95% for pristine ES, and the activation energy and potential window of the SR gel electrolyte was close to that of pristine ES. The compressive properties of the SR gel electrolyte were also investigated; the Young's modulus of the SR gel electrolyte decreased with the crosslinking density and the SR gel electrolyte with a low crosslinking density was not fractured under compression to almost half of the original thickness.