Conductivity of a confined polymer electrolyte: lithium-polypropylene glycol intercalated in layered CdPS₃

Abstract

Lithium cations solvated by polypropylene glycol were confined, by intercalation, in the interlamellar space of an insulating layered solid, CdPS₃. The conductivity and the associated relaxation processes were investigated as a function of temperature and compared with corresponding bulk solid polymer electrolyte (SPE). The conductivity of the confined polymer electrolyte, which is comparable with that of bulk SPE, follows the Vogel-Tamman-Fulcher relation characteristic of ionic motion coupled to polymer relaxation modes and, surprisingly, these processes, although broadened, are faster than that in the corresponding bulk solid polymer electrolyte. The absence of ion-pair formation and anion transport makes Cd_0.75PS₃Li_0.5(PPG) an ideal system for investigating ionic motion in disordered polymer matrices.