高安全性PEO-Al2O3复合隔膜的制备及电化学性能

Synthesis and Electrochemical Performance of PEO-Al2O3 Hybrid Membrane for High Safety Lithium-ion Batteries

本工作以聚氧化乙烯(PEO)和氧化铝(Al2O3)为原料,利用刮涂法制备了一系列PEO-Al2O3复合隔膜,探索了Al2O3添加量对PEO-Al2O3复合隔膜的性能影响。采用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线能量色散谱仪(EDS)、X射线衍射仪(XRD)、红外光谱(FTIR)、X射线光电子能谱分析(XPS)、热重分析(TG)及燃烧实验法对复合隔膜的形貌、元素分布、相组成、表面化学状态和热稳定性进行表征。通过线性扫描伏安法(LSV)、电化学交流阻抗法(EIS)、孔隙率测试和吸液率实验考察了复合隔膜的电化学窗口、离子电导率、孔隙率和吸液率。实验结果显示,PEO-Al2O3-90复合隔膜具有最高的离子电导率(1.21×10^-3S/cm)、最大的吸液率(260%)、较好的热稳定性、较高的孔隙率(47%)以及较宽的电化学窗口(0~4.8 V)。通过组装电池发现,PEO-Al2O3-90复合隔膜电池在电流密度为0.1C时表现出较高的放电比容量、优异的循环稳定性以及较强的安全性。

In this work,a series of polyethylene glycol oxide(PEO)-aluminium oxide(Al 2O 3)hybrid membranes were prepared by a slurry coating method.The effect of the mass ratio of PEO/Al 2O 3 on the performance of PEO-Al 2O 3 hybrid membranes was systematically investigated.Scanning electron microscopy(SEM),transmission electron microscope(TEM),X-ray energy dispersive spectroscopy(EDS),X-ray diffraction(XRD),Fourier transform infrared spectra(FTIR),X-ray photoelectron spectroscopy(XPS),thermogravimetric analysis(TG)and combustion test were performed to reveal the morphology,element distribution,phase composition,surface chemical state and thermal stability of PEO-Al 2O 3 hybrid membranes.In addition,linear sweep voltammetry(LSV),electrochemical impedance spectroscopy(EIS),porosity and electrolyte uptake test were employed to investigate the electrochemical stability,ionic conductivity,porosity and electrolyte uptake of PEO-Al 2O 3 hybrid membranes.The results showed that PEO-Al 2O3-90 hybrid membrane had a high ionic conductivity(1.21×10^-3 S/cm),high electrolyte uptake(260%),good thermal stability,high porosity(47%)and wide electrochemical stabilization window(0—4.8 V).At the current density of 0.1C,LiFePO4|PEO-Al2O3-90|Li cells assembled with PEO-Al 2O3-90 hybrid membrane exhibited a high discharge specific capacity,superior cycling stability and enhanced safety.