Preparation And Performance Studies Of PVDF-HFP Polymer Electrolyte Used In Batteries

In this article, the Bellcore method was used to prepare polymer electrolyte membrane based on PVDF-HFP, and polymer electrolyte membranes under different conditions were prepared by changing sorts of solvents,ratio of DBP and solvent. Effects of ratio of plasticizer and solvent on the liquid uptake,SEM,mechanism capability,ionic conductivity,electrochemical stability window of polymer electrolyte membrane were also studied. Through optimizing the preparation technics, the integrated effects of additives such as PC,EC,DBP and nanophase Al2O3 on the ionic conductivity,liquid uptake were studied. After adding some ratio of DBP, pores in the polymer electrolyte membrane increased, liquid uptake got larger and the ionic conductivity increased from 10-5 S·cm-1 to 10-3 S·cm-1, but the mechanism intension slowed down. Through the test of XRD and FTIR, it was found that in the testing chart there were no characteristic apices of DBP, so we can conclude that the plasticizer of DBP were removed entirely.Solvents of DMAC and NMP were used to prepare polymer electrolyte membrane, when the ratio of DBP and solvent was 20%, both of the ionic conductivity can arrive at 10-3 S·cm-1, and the ionic conductivity of polymer made by NMP was 35% higher than by DMAC. From SEM of the polymer , we can found that, the polymer containing no DBP made by solvent of NMP had more and large pores than solvent of DMAC, so it had larger liquid uptake and higher ionic conductivity.The liquid uptake of polymer electrolyte membrane first increase, then remaining the same as the increasing of ratio of solvents. Mechanism capability and ionic conductivity fist increase then decrease during the process, but it changed not much in total. Through the test of SEM it can be found that the structure of membrane changed little during the process.The preparation technics of polymer membrane was optimized through orthogonal test. A fact that the electrochemical stability window of all the polymer membrane were within the using bound was discovered in the experiment, but the electrochemical stability window preparaed by orthogonal...