Improved battery performance contributed by the optimized phase ratio of β and α of PVDF

Abstract

Inorganic salts (LiCl) were induced to improve the ratio of β and α of PVDF by the solution method. The vibrational spectra of PVDF polymorphic polymers were obtained by Fourier transform infrared spectroscopy (FTIR), and the results showed that the ratio of β and α of pristine PVDF was elevated from 43.66% to 53.27%. A small amount of LiCl grains was detected to be decorated on the surface of LiCl-involved electrodes by the SEM and EDS tests. The rate capability of the modified samples was evaluated when charge-discharged at 5C. The capacity of the 1/10LiCl@PVDF samples remained at a high level of 71.64% when charge-discharged at 5C, which was much higher than the value of 54.66% for pristine samples. The results of the CV and EIS tests revealed that the electrochemical polarization increasing rate and charge transfer resistance of the 1/10LiCl@PVDF samples were smaller than those of the pristine PVDF samples.