New Polymer Electrolytes For Lithium Ion Batteries

The researches of polymer electrolytes for Li-ion Batteries are summarized. Novel PMMA-VAc-based Gel Electrolyte cross-linked by N,N'-methylenebis-acr ylamide for lithium ion battery is prepared. As the network structure, the mechanical property of the gelled electrolyte is improved. The content of MMA, VA -c, N,N'- methylenebisacrylamide and DBP are optimized, and the conductivity is investigated. The conductivity reaches 1.21×10^-4 S·cm^-1 in the polymer electrolyte (PMMA: VAC=1:0.5) containing 0.05% N,N'-methylenebisacrylamide (mass fraction) in ethylene carbonate (EC)/dimethyl carbonate (DMC) at room temperature. The polymer lithium ion battery with gelled PMMA-VAc electrolyte exhibits good electrochemical and mechanical property when PMMA-VAc: DBP=1:0.75. A copolymer P(MA-AN-IALi)( PMAIL) was synthesized by solution polymerization. It was made by solution casting, and the nor-solvent or extraction step was unnecessary in this process. A novel gelled polymer electrolyte based on PMAIL was obtained by soaking the polymer membrane in organic liquid electrolytes. The surface structure of the polymer film was characterized by SEM. The pores were well distributed in the surface of the membrane. The ionic conductivity of the polymer electrolyte was measured by the AC impedance method, it was about 1.89×10^-4 S·cm^-1 at room temperature. The test results display that the polymer electrolyte based on PMAIL was electrochemical stable and can be used in lithium ion batteries.Electrolytes play an important role in the study of lithium-ion battery. If we want to improve its conductivity, we should search for a new lithium salt as lithium-ion batteries. In this paper, I do some explorations and experiments in search for new lithium salts: itaconic acid react with LiOH or Li₂CO₃. In addition, we synthesized several electrolytes such as LiBOB and Li₅BOB.