Preparation And Properties Study Of Fluorine Lithium Polystyrene Sulfonate Electrolyte

Electrochemical energy storage is one of the main societal challenges to humankind in this century.The performances of classical Li-ion batteries(LIBs)with non-aqueous liquid electrolytes have made great advances in the past two decades,but the intrinsic instability of liquid electrolytes results in safety issues,and the energy density of the state-of-the-art LIBs cannot satisfy the practical requirement.Compared to liquid lithium-ion batteries,polymer-based polymer lithium-ion battery with better practicality and safety,which can be applied to a wider range of areas.Traditional SPEs are dual-ion conductors,in which both cations and anions are mobile and will cause a concentrat ion polarization thus leading to poor performances of both LIBs and LMBs.Single ion polymer electrolyte has increasingly become the focus of researches for its advantages of solid polymer electrolyte on the basis of avoiding the defects of the two-ion conductor,But the ion conductivity of single ion polymer electrolyte is too low to used in lithum batteries.In this paper,three kinds of novel polymer electrolytes were prepared and their properties were analyzed to increase the ion conductivity of single ion polymer electrolyte.This paper first successfully prepared lithium polystyrene sulfonate electrolyte with Li+/EO=1:18 content different methacrylic acid hexafluoro butyl.By hydrogen nuclear magnetic resonance spectrum,infrared spectroscopy,scanning electron microscopy and,energy dispersive spectrometer,the structure of polymer were detected,the glass transition temperature and thermal stability of polymers were analyzed by differential scanning calorimetry and thermogravimetric analysis,electrochemical impedance spectroscopy and lithium ion transference numbers were texted to characterization the electrical performance of the electrolyte membranes.Based on the effects of the concentration of hexafluorobutyl methacrylate and the ratio of Li+/EO on the ionic conductivity of polymer electrolytes,a series of polymer electrolytes with different hexafluorobutyl methacrylate concentration were prepared under Li+/EO=1:27.The same analytical methods were adopted to analysis the structure and the properties of the polymer electrolytes.The effects of fluorine content on performance were studied.Finally,the polymer electrolytes with Li+/EO=1:27 doping with nano-silica were sythesised,the same analytical methods were adopted to analysis the structure and the properties of the polymer electrolytes.The effects of nano-silica content on performance were studied.By measuring the glass transition temperature of polymers by differential scanning calorimetry,it showed that glass transition temperature increased with the increasing content of hexafluorobutyl methacrylate and nano-silica of the three series polymer electrolytes.The biggest ion conductivity for polymer electrolyte with Li+/EO=1:18 is 8.7×10-7S/cm with hexafluorobutyl methacrylate content rised to 30%,polymer electrolyte with Li+/EO=1:27 is 6.9×10-6S/cm with hexafluorobutyl methacrylate 20%,polymer electrolyte with Li+/EO=1:27 doping with nano-silica is 7.7×10-5S/cm with content of nano-silica up to 0.6%.Lithium ion transference numbers increased with the increasing content of hexafluorobutyl methacrylate or nano-silica contents for the three kinds of polymers.The mechanical properties of polymer electrolytes meet the practical application.