| With the continuous development of the times,People urgently need a new,efficient and green energy source to adapt to the development of today's society.As the most influential energy storage equipment in the 21st century,lithium-ion batteries have attracted people's attention and are widely used in various fields such as industry and life.However,the existing lithium-ion batteries still have many shortcomings.In this paper,several new polymer electrolytes have been prepared and studied in the field of lithium-ion battery electrolytes.First,cellulose acetate CA with different mass fractions was added to the P?VDF-HFP?-PEO polymer system,a series of membranes with different mass ratios were prepared by phase inversion method,and a gel polymer electrolyte was formed with LiClO4 solution?GPE-LiClO4?.After the characterization of the diaphragm and GPE,SEM and liquid absorption test results show that the pore structure of CA15%-P?VDF-HFP?-PEO diaphragm is good,the distribution is more uniform,and the liquid absorption effect is significant,which will be beneficial to lithium ion Transmission;AC impedance method measured the ionic conductivity of this ratio of GPE at room temperature reached 5.15×10-3S·cm-1;TGA and DSC characterization results found that the addition of CA changed the hot melt properties of the system and reduced the crystallinity of PEO,At the same time,no thermal decomposition occurs at 250?;afterwards,the Li/15%CA-GPE-LiClO4/SS system was subjected to LSV test,and the electrochemical window was found to be 4.5V,which meets the general lithium ion battery use conditions.Three kinds of boron-containing lithium salts LBOB,LBBB,FLBBB were successfully synthesized,and three kinds of GPE?GPE-LBOB,GPE-LBBB,GPE-FLBBB?were prepared using CA15%-P?VDF-HFP?-PEO membrane as polymer matrix.the ionic conductivity at room temperature of the three GPEs was found to be 10-3S·cm-1 by AC impedance test.Later,GPE-FLBBB was selected as the electrolyte to assemble Li/GPE-FLBBB/SS half-cells and LiFePO4/GPE-FLBBB/Li full cells,respectively.The related electrochemical performance was studied.The conclusion is as follows:The oxidation potential of GPE-FLBBB reaches4.25V The results of charge and discharge experiments at this voltage indicate that the GPE-FLBBB battery has a high battery capacity,and the capacity at 0.1C reaches175mAh·g-1.After 100 cycles,it was found that the GPE-FLBBB battery still maintained good battery capacity and coulomb efficiency.It shows the potential application value of GPE-FLBBB as an electrolyte for lithium ion batteries.Finally,three all-solid electrolytes?SPE-LBOB,SPE-LBBB,SPE-FLBBB?were prepared by using three kinds of LBOB,LBBB,FLBBB as lithium electrolyte salts and P?VDF-HFP?-PEO as polymer matrix.SEM and XRD characterization confirmed that the boron-containing lithium salt can be uniformly dispersed in the P?VDF-HFP?-PEO system.The results of thermogravimetric analysis of the three SPEs were discussed.The strongest interaction between LBOB and the polymer matrix was found.Later,the electrochemical performance of the three SPEs was tested using AC impedance method and LSV.The results showed that the ionic conductivity of the three SPEs reached 10-5S·cm-11 at room temperature and all had wide electrochemical windows. |
PDF Full Text Request