Manufacture Of Solid Polymer Electrolytes

Solid polymer electrolyte was the key points which made rechargeable lithium-ion polymer batteries with high safety, thin, flexibility in the shape of a cell design. Solid polymer electrolyte has been extensively studied in recent years in the world. But from a practical point of view, Solid polymer electrolyte must satisfy certain minimal requirements on ionic conductivity, thermal, and electrochemical stabilities. The preparation and measuration of P(VdF-HFP)-based polymer electrolyte were investigated. The major contributions include the following aspects: Gel-type polymer electrolytes based on P(VdF-HFP)-LiClO4-EC/DMC were prepared by using solvent casting method, the content of every component was optimized and gel-type polymer electrolytes were improved by nanometer SiO2. The conductivities of polymer electrolytes were measured and the electrolytes membrane were investigated by Fourier transform infrared spectroscopy(FT-IR) , Scanning electron microscopy(SEM) , X-ray diffraction(XRD) and differential scanning calorimetry(DSC). The measurements on the conductivity of the membranes with different compositions have shown that conductivities reach maximums (2.81mS/cm),DSC showed that the membranes are amorphous from -20℃ to 100℃; It was electrochemically stable, ie △V= 4.3V. Porous polymer electrolytes based on P(VdF-HFP)-SiO2-LiPF6-EC/DMC/DEC and P(VdF-HFP)-LiClO4-SiO2-EC/DMC were prepared by using phase inversion method. The content of every component was optimized. The conductivities of polymer electrolytes were measured and the electrolytes membrane were investigated by SEM, XRD and DSC. The measurements on the conductivity of the membranes with different compositions have shown that conductivities reach maximums (4.38mS/cm),DSC showed that the membranes are amorphous from -20℃ to 76℃; It was electrochemically stable, ie △V= 5.0V. Porous polymer electrolytes based P(VdF-HFP)-TiO2-LiPF6-EC/DMC/DEC and P(VdF-HFP)-LiPF6-SiO2-EC/DMC were prepared by using optimized phase inversion method. the content of every component was optimized. the conductivities of polymer electrolytes were measured and the electrolytes membrane were investigated by SEM , XRD and DSC. The measurements on the conductivity of the membranes with different compositions have shown that conductivities reach maximums (4.11mS/cm),DSC showed that the membranes are amorphous from -20℃ to 97℃; It was electrochemically stable, ie △V= 5.0V. Structure and performance of Porous polymer electrolyte prepared by using phase inversion method or optimized phase inversion method were similar, but porous polymer electrolyte prepared by using optimized phase inversion method have more thermal stability and electrochemical stability.