Study Of MMA-OE Based Solid Polymer Electrolyte

At p resent,commercial electrolytes comprising organic liquid endows itself disadvantages such as easy leakage,volatility,flammability and explosion.The solid polymer electrolyte?SPE?has become a research hotspot due to its low cost,good interface stability,excellent film f'ormation and plasticity.However,problems such as low conductivity and poor electrochemical stability limit its application.This thesis systematically studied the random and diblock polymer electrolyte of MMA and OE.In addition,the new third monomers are introduced to prepare novel ternary random copolymer electrolyte,which have high conductivity.The basic structure and physical properties of the polymer are characterized,and the electrochemical performance are tested and analyzed.The specific research contents and results are as follows:?1?The electrolyte material PMOs are synthesized by radical polymerization.PMO are successfully prepared with diff;erent monomer ratios of OE and MMA and verified by1H NMR,FTIR and GPC.The DSC test shows that T_g of PMO system decreases with the increasing OE content,and T_g of all polymers are lower than-40 ?,When the LiClO4 content reached 50 wt%,the ionic conductivity of the PMO-SPE reached a maximum of 9.30×10^-7 S/cm.The electrochemical stability windows are f'rom 4.6V to 4.7 V,and the interface stability between PMO electrolyte and Li is good.?2?Diblock copolymer B-PMO are successfully prepared by RAF T polymerization.The molecular weight and T_g were characterized by GPC and DSC,respectively.The electrochemical properties of B-PMO electrolyte are tested:When the B-PMO have highest OE content with 50 wt%LiClO4,the maximum ionic conductivity reach 6.49×10^-7 S/cm at room temperature.The decomposition voltage is up to 4.5 V.At the same time,the interface between B-PMO electrolyte and Li have good stability.?3?Ternary random copolymers are prepared based on MMA and OE by introducing different new monomers,i.e.maleic anhydride?MA?,vinylene carbonate?VC?and vinylpyrrolidone?VP?,where OE:MMA:third monomer feed ratio is fixed at 7:3:2.The M_n and T_g of terpolymers are characterized by GPC and DSC,the results show that the molecular weights of them are similar and the T_g of Tri-VC is the lowest.The highest room temperature conductivity of Tri-MA,Tri-VC and Tri-VP at 50 wt%LiClO4 reaches 2.14×10^-6 S/cm,2.67×10^-6 S/cm and 2.82×10^-6 S/cm,respectively.Compared with PMO and B-PMO system,the conductivity is greatly improved.Electrochemical stability windows of terpolymers are from 4.8 V to 5.0V.The terpolymer electrolytes have good interface compatibility with the Li.