Study on performances of ZSM-5 doped P(VDF-HFP) based composite polymer electrolyte prepared by steam bath technique

Abstract

Several novel kinds of poly (vinylidene fluoride-co-hexafluoropropylene) (P(VDF-HFP)) based composite polymer electrolyte (CPE) membranes doped with ZSM-5 (Zeolite sieve of molecular porosity) were fabricated by steam bath technique. The desirable CPE membranes were further prepared by immersing them into the liquid electrolyte solution of 1.0 M LiPF6-ethylene carbonate /dimethyl carbonate/ethylmethyl carbonate (v/v/v:1/1/1) for 1 h to be activated at room temperature. Physical and chemical properties of the as-prepared CPEs are studied by scanning electron microscope, Fourier transform infrared, thermogravimetry and differential scanning calorimetry and electrochemical methods. The results showed that the thermal and electrochemical stabilities of the CPEs can be reached to 350 °C and 5 V, respectively. Reciprocal temperature dependence of corresponding ionic conductivity follows Vogel–Tamman–Fulcher relation, and ionic conductivity at ambient temperature can be up to 5.1 mS cm−1. The fabricated Li/CPEs/LiCoO2 coin cells with the CPE membranes prepared by steam bath technique can achieve a high discharge capacity about 144.97 mAh g−1 at 0.1 C. At 1.0 C, the capacity can be kept to 89.84 % of that at 0.1 C for the cell. After 26 cycles, the cell prepared with these CPE membranes can keep 97.5 % of its initial discharge capacity. These excellent physicochemical and battery properties indicate that these novel CPEs can be potentially used as electrolyte in lithium ion polymer battery.