【作者】 王利；

【导师】 潘颐；

【作者基本信息】 浙江大学 ， 材料加工工程， 2005， 硕士

【摘要】 聚合物电解质是由盐与聚合物基体共混后形成的离子导体,它们在二次锂电池和其他电化学显示设备中的应用已经引起人们研究的极大兴趣。通常研究最多的聚合物电解质是由聚环氧乙烷(PEO)和一些锂盐构成的,在这些聚合物电解质中,离子的迁移导电主要是通过聚合物分子链的松弛运动完成的,而且是发生在聚合物电解质的无定形相部分中。但PEO和一些锂盐形成的聚合物电解质因为体系结晶度较高影响了室温下的电导率值,从而限制了它们的应用。当结晶度降低后,聚合物电解质便拥有快的离子迁移性并能获得很高的电导率。在本论文中,主要的研究内容是从师兄王严杰博士的研究工作中选取电导率数值较好的PEO-LiclO4-Li1. 3Al0. 3Ti1. 7(PO4) 3三相体系(EO/Li 摩尔比为8、 Li1. 3Al0. 3Ti1. 7(PO4) 3盐含量为15%),再添加不同质量百分数的增塑剂EC、PC以及两者的混合体,通过溶液浇铸法制成复合聚合物电解质薄膜,再通过XRD、DSC、SEM和EI等测试手段研究了增塑剂改性的PEO基聚合物电解质的结构、热性能、表面形态与电导率。通过研究发现在(PEO/增塑剂-LiClO4) -Li1. 3Al0. 3Ti1. 7(PO4) 3聚合物电解质体系中,无定形相为主要相态,电导率随温度升高而增大,且电导率与温度关系遵循VTF方程,而锂离子的迁移主要与无定形区的链段运动息息相关。并且指前因子(A)和表观活化能(Ea)增大趋势符合电导率随增塑剂含量增大而增加情形,在增塑剂含量达到体系含量40%时指前因子(A)、表观活化能(Ea)和电导率分别取得最大值,如在增塑剂含量为40%时,室温下电导率达到10-3S·cm1-。更多还原

【Abstract】 The polymer electrolytes, as ionic conductors, which consist of a salt dissolved in a polymer host, in applications such as rechargeable lithium batteries and other electrochemical devices have attracted more and more interest. The most investigated systems consist of poly（ethylene oxide）, PEO, with dissolved salts. Ionic transport in these systems is highly coupled to the relaxation processes of the polymer backbone and has been determined to occur predominantly in the amorphous phase for polymer electrolytes. Because of high crystallinity, these electrolytes with PEO and dissolved salts suffer from low conductivity values at room temperature so that the applications are restricted for the polymer electrolytes which result in fast ion mobility and therefore high conductivities with low crystallinity.In this paper, I primarily focused my work on adding different percent mass of EC PC or the mixture of them to the trinomial system PEO-LiClO₄ -Li1.3Al0.3Ti1.7（PO4）3 with E0/Li=8 and 15wt.% -Li1.3Al0.3Ti1.7（PO4）3 content which carefully selected from the scientific research of Doctor Yan-Jie Wang. The polymer electrolyte films was prepared by by a solution-cast method. Several techniques including X-ray diffraction （XRD）, DSC, SEM and electrical impedance （El） measurement were used to investigate the structure, thermal property, morphology and conductivity of these polymer electrolytes. It is found by study that the amorphous phase dominated in the prepared （PEO/plasticizer-LiClO4）-Li1.3Al0.3Ti1.7（PO4）3 polymer electrolyte system, where the temperature dependence of conductivity follows Vogel-Tamman-Fulcher （VTF） equation while the conductivity increase with the increasing temperature. Additionally the migration of lithium cations depends mainly on the segmental movements of the polymer chain in the amorphous region. Both the pre-exponential factor （A） andthe pseudo activation energy （Ea） monotonously increase with the increase of plasticizer content in the polymer electrolyte （PEO/plasticizer-LiC104）-Li1.3Al0.3Ti1.7（PO4）3), suggesting that ion migration easily happen and the increase of pre-exponential factor agrees with the increase of conductivity of the polymer electrolyte films with EC PC or the mixture of them. At 40wt. % plasticizer content, the conductivity, when the pre-exponentialfactor （A） and the pseudo activation energy （Ea） respectively have a maximum, is optimal, and the conductivity value is 10-3 S cm-11 at room temperature.更多还原