Synthesis And Properties Of Nano-TiO₂/PVDF-HFP Microporous Memebrane

In the components of the lithium-ion battery, the membrane played an important impacton the performance of the lithium-ion battery. The polyvinylidene fluoride-hexafluoro-propylene （PVDF-HFP） can provide high dielectric constant, good heat resistance, chemicalcorrosion resistance, electrochemical properties, which is suitable for lithium-ion batteryseparator material. But it has shortcomings of the film is brittle, poor toughness, highcrystallinity, which limiting the application in the membrane material.In order to resolve the problem of low liquid absorbent, poor mechanical properties andlower heat resistance, we improved the performance of membrane material using methylmethacrylate （MMA）,polyethlene glycol dimethacrylate （PEGDMA）,N-methyl-pyrrolidone（NMP）, nano TiO₂.We researched the performance of the membrane prepared by nano-TiO₂/PVDF-HFP. Theanalysis showed that the optimum consistence of the solution was5%, the optimumtemperature is70℃which was needed by polymerization built chain and network structure ofMMA and PEGDMA, and the optimum time of polymerization is6hours. And the singlefactor analysis showed that the optimum mol rate of PVDF-HFP, MMA, PEGDMA was8:4:1,and mess rate of NMP and PVDF-HFP was2:1.The liquid absorbing rate analysis showed that when the TiO2mass percentage was15%,the membrane got the highest liquid absorbing rate, reached to190%more than the othercondition. The analysis of mechanical behavior showed that the tension rose firstly and thenreduced gradually as increasing the mass rate of TiO₂in PVDF-HFP, and we found theoptimum mechanical performance when mass rate was15%. The analysis of TG showed thatits decomposing temperature up to250℃when the mass rate of TiO₂in PVDF-HFP, whichcould achieve the demand of thermal property in lithium battery separator. The analysis oficonic conduction showed that the iconic conduction was equaled to5×10-4S·cm^-1 when the mass rate of TiO₂in PVDF-HFP was5%,10%and15%.