NMR Studies Of Solid Electrolyte Interface And Phase Structure

In this work,a method of studying the phase structure of semicrystalline polymers based on solid ~1H wide-line experiment is developed.At the same time,solid statenuclearmagneticresonance(ss-NMR)combinedwith other characterization techniques is used to study two kinds of polymer complex systems.The main results are shown below.1?The ~1H wide-line spectrum of semicrystalline polyethylene is studied.The combination of the Gaussian/Sinc,Gaussian and Lorentzian functions is used to fit the~1H wide-line of semicrystalline polyethylene.Four signal components decomposed from the ~1H wide-line spectra are assigned to the crystallization phase,crystalline interface phase,amorphous interface phase and amorphous phase.On the signal assignment,the chain dynamics in different phase is studied via the temperature dependent ~1H wide-line NMR.The feasibility of determining the crystallinity of semicrystalline polymer via ~1H wide-line NMR is discussed afterwards.2?Several semicrystalline polymer electrolytes with controlled structure are designed and fabricated by controlling lithium concentration and different thermal progress.The different phase structure of solution crystallized samples and annealing samples are studied by DSC,XRD.The conductivity of sample is measured by EIS.At last solid-state NMR is used to analyze the crystallinity.3?By means of SEM and XRD,the polymer is found as amorphous phase in the polymer-lithium salt-ceramic complex.The motility of the molecules and the temperature dependence of signals are studied by static ~1H and ~7Li NMR experiments.According to ~1H-~7Li CP MAS experiments,the interface signals are assigned and discussed.Finally,~1H-~7Li WISE experiments are applied to study the interface of polymer motility and its temperature dependence.