分子间相互作用对复合固态聚合物电解质离子电导率的影响机制

以聚氧化乙烯(PEO)为基体、埃洛石纳米管(HNTs)为填料,采用溶液浇铸法制备了系列聚氧化乙烯/高氯酸锂/埃洛石(PEO/LiClO_4/HNTs)固态聚合物电解质。系统研究了HNTs经表面改性前后对PEO结晶性能、锂盐解离度及离子电导率的影响机制。透射电子显微镜和比表面积表征结果表明,HNTs经硫酸处理后(A-HNTs),可在保持纳米管形貌的基础上使其比表面积从33.15 m~2/g增加到104.73 m~2/g; X射线衍射和差示扫描量热法分析结果表明,HNTs经表面改性处理,可增加分子间的相互作用,进一步降低PEO的结晶度;光学显微镜结果证明,HNTs的加入可使PEO球晶尺寸减小,表面改性处理可进一步使PEO结晶细化;傅里叶变换红外光谱和离子电导率测试结果表明,通过对HNTs纳米管表面基团的控制,可以提高LiClO_4解离程度,获得的电解质膜在40℃的离子电导率高达1.35×10~(-4) S/cm。     

(PEO)8LiClO4-TiO2复合电解质膜的制备表征及导电性能

以聚氧化乙烯/高氯酸锂复合物(简记为(PEO)8L iC lO4)为基体,通过钛酸丁酯的水解缩合反应在其中原位生成T iO2粒子,制备了(PEO)8L iC lO4-T iO2复合聚合物电解质膜,采用原子力显微镜(AFM)、差示扫描量热法(DSC)和交流阻抗方法研究了复合电解质膜的形貌、结晶、熔融行为和离子电导率。结果表明,T iO2粒子在基体中分散均匀,加入T iO2后复合电解质体系的玻璃化转变温度和结晶度均有所下降,而电导率明显提高,当T iO2添加量为5%时电导率最大,20℃和80℃的电导率分别为5.5×10-5S/cm和1.1×10-3S/cm。     

PVA-PEO碱性聚合物电解质的制备与表征

通过溶解-铸膜法制备了聚乙烯醇(PVA)-KOH-H2O碱性聚合物电解质膜,并向电解质中加入聚氧化乙烯(PEO)来提高离子电导率。X射线衍射(XRD)和红外光谱(FT-IR)结果表明,PEO的加入一定程度上降低了结晶度,薄膜处于无定型态。扫描电镜(SEM)表征结果显示薄膜呈非均匀网络微孔结构。交流阻抗结果表明,该薄膜室温离子电导率在mPEO/m(PVA+PEO)=0.2时达最大,为2.78×10-2S/cm。循环伏安结果表明该薄膜具有较好的电化学稳定性。     

LATP-PEO复合电解质成膜及离子电导率特性

以纳米Li_(1.3)Al_(0.3)Ti_(1. 7)(PO_4)_3(LATP)固体电解质为填料,聚氧化乙烯(PEO)为粘结剂,双三氟甲烷磺酰亚胺锂(Li TFSI)为添加剂,乙腈为溶剂,利用流延法制备LATP-PEO固体复合电解质薄膜;采用X射线衍射(XRD)、扫描电镜(SEM)和交流阻抗(EIS)等方法,研究样品的结构特征、形貌特征以及离子导电性能;探讨PEO摩尔质量与含量对LATP-PEO复合电解质薄膜成膜特性的影响。结果表明:PEO摩尔质量为5 000 kg/mol,LATP与PEO质量比为1∶0. 43时,可以获得膜厚为25μm,颗粒分布均匀的柔性LATP-PEO; LATP-PEO离子电导率随温度增高而增大,25℃时为1. 36×10~(-5)S/cm,100℃达到4. 60×10~(-4)S/cm;温度在-20～60℃时,该薄膜离子活化能为4. 86 eV,温度在60～100℃时,离子活化能为0. 22 eV。     

PEO-Li1.3Al0.3Ti1.7(PO4)3复合聚合物电解质的制备与电导率研究

将实验室制备的两种烧结型的Li1.3Al0.3Ti1.7(PO4)3盐与PEO/LiClO4复合,制得了PEO-LiClO4-Li1.3Al0.3Ti1.7(PO4)3复合聚合物电解质,测量了298～373K温度范围内的阻抗,得出这种体系的复合聚合物电解质的离子电导率在室温最高值为1.387×10-5S/cm,在373K时可达到1.378×10-3S/cm.     

基于高电导率的疏水气相SiO_2复合凝胶电解质的高性能电致变色器件（英文）

凝胶电解质具有化学稳定、难燃和易于封装等特点,其低离子电导率(10~(–4)～10~(–5) S·cm~(–1))阻碍了电致变色器件(ECDs)凝胶电解质的进一步发展。本研究制备了一种高电导率的疏水SiO_2/PMMA/PC/LiClO_4凝胶聚合物电解质(H-SiO_2 GPEs),并用电化学阻抗谱(EIS)、循环伏安法(CV)和计时电流法(CA)分析了ECDs的电化学行为。实验结果表明,仅引入0.5wt%的疏水性气相SiO_2,即可使H-SiO_2 GPEs的离子电导率达到5.14mS·cm~(–1)(25℃时)。离子电导率的增加归因于SiO_2添加物和有机电解质之间良好的相容性和疏水–疏水吸引力促进了高氯酸锂的离解。同时,不同气相二氧化硅含量的GPEs的粘度与剪切速率的关系表现出剪切稀化行为,这表明研究体系形成了三维网状结构。该结构为离子提供了传输通道,进而提高了基于H-SiO_2GPEs电致变色器件的响应速度(t_(bleaching)=4 vs 8 s和t_(coloring)=14 vs 16 s)。同样,通过探究添加疏水性气相SiO_2对液态电解液的影响表明:复合疏水性气相SiO_2使得LiClO_4/PC液态电解液的离子电导率由原来的6.94 mS·cm~(–1)增大到7.58 mS·cm~(–1)。疏水性气相SiO_2作为填料对电解质的离子电导率具有一定的积极作用, H-SiO_2GPEs的研究为解决ECDs高离子电导率和易泄漏之间的矛盾提供了新思路。     

微波低温烧结快速制备Na1+xZr2-xFex(PO4)3陶瓷固态电解质

根据NaZr_2(PO_4)_3(简称NZP)的晶体结构特征和电荷补偿机理,通过掺入Fe~(3+)对NZP固态电解质进行改性,采用微波烧结工艺在950℃保温1.5 h制备了Na_(1+x)Zr_(2-x)Fe_x(PO_4)_3(x=0, 0.1, 0.2, 0.3, 0.4)陶瓷电解质,系统研究了Fe~(3+)掺入量对电解质的物相组成、微观形貌、相对密度以及离子电导率的影响规律。研究结果发现,利用微波烧结工艺,经950℃处理1.5 h后,成功制备出单相、致密的Na_(1+x)Zr_(2-x)Fe_x(PO_4)_3陶瓷电解质,与传统固相烧结相比,极大降低了烧结温度、缩短了制备周期。且随着Fe~(3+)掺入量的增加,样品的相对密度增大,最大为93.8%。阻抗测试结果表明,Fe~(3+)的掺入可提高样品的离子电导率,当Fe~(3+)掺量为0.3～0.4,室温离子电导率约为6.5×10~(-6) S/cm,高温(573 K)下离子电导率达到1.56×10~(-3) S/cm。     

纳米CeO2对(PEO)10LiClO4电解质体系电学和力学性能的影响

以乙腈为有机溶剂,以高纯纳米稀土氧化物CeO2为无机填料,采用溶液浇铸法制备了(PEO1)0Li-ClO4-x%(质量分数)CeO2(x=0、2、6、9、12、15)全固态复合聚合物电解质(CPE)薄膜。交流阻抗测试表明,适量添加CeO2可有效抑制PEO结晶并拓展锂离子传输所需的无定形区域,从而使CPE薄膜的离子电导率有明显提升,当CeO2的含量为9%(质量分数)时,CPE的离子电导率达到最大值,25℃时为1.71×10-5S/cm,但过量CeO2对锂离子传输具有一定的阻碍,XRD图像证实了这一结论。同时,CeO2的引入可很好地分散和传递应力,对CPE的韧性有明显增强作用,当CeO2的含量为15%(质量分数)时,拉伸强度达到2.07MPa,提高了4.45倍。     

原位复合法制备TiO2 / ( PEO)8LiClO4 聚合物电解质

以聚氧化乙烯/ 高氯酸锂络合物( ( PEO)₈LiClO₄ ) 为基体, 通过钛酸四丁酯的水解缩合反应在基体中原位生成TiO₂粒子, 制备了TiO₂ / ( PEO)₈LiClO₄复合聚合物电解质膜。采用SEM、DSC 和交流阻抗方法分别研究了电解质膜的表面形貌、热性能和离子导电性能。结果表明, 原位生成的TiO₂ 粒子均匀分散于PEO 基体中。复合TiO₂后电解质膜的玻璃化转变温度和结晶度降低。电解质膜的离子导电行为满足Arrhenius 方程, 并在5 %TiO₂含量时体系的电导率出现最大值5. 5 ×10 -5 S/ cm (20 ℃) 。以此膜为电解质组装的全固态聚合物锂电池放电时电压平稳, 20 次循环后放电容量保持在107 mAh/ g。      

PEO基固态聚合物电解质膜的静电纺丝制备及性能EI北大核心CSCD

PEO基固态聚合物电解质被认为是目前固态锂电池领域极具产业化前景的固态电解质。为适应工业化生产,采用静电纺丝技术制备PEO/LiClO_(4)固态聚合物电解质(SPE),研究纺丝电压、纺丝液质量浓度和锂盐含量对SPE纤维膜形貌和直径的影响。通过扫描电子显微镜观察SPE中纤维的形貌,利用Image J软件分析SPE纤维的直径。通过DSC,XRD,FTIR-ATR和拉伸测试等手段对静电纺丝制备的SPE纤维膜的组成、结构、性能等进行研究。结果表明:当纺丝电压为15 kV、PEO/LiClO_(4)纺丝液质量浓度为6%、[EO]∶[Li^(+)]=10∶1(摩尔比)时,静电纺丝方法制备的PEO/LiClO_(4) SPE纤维膜具有较好的纤维形貌,平均直径为557 nm,分布均一;当[EO]∶[Li^(+)]=10∶1时,SPE纤维膜中PEO的熔点仅为53.8℃,结晶度低至18.9%;电解质在30℃时的离子电导率达到5.16×10^(-5)S·cm^(-1),同时具备良好的电化学稳定性和界面稳定性。     

La0.5Y0.5Ni4.8Mn0.1Al0.1和La0.5Y0.5Ni4.8Al0.2合金的储氢性能研究

针对两种新型稀土型储氢合金La0.5Y0.5Ni4.8Mn0.1Al0.1和La0.5Y0.5Ni4.8Al0.2的储氢特性进行研究分析。实验表明,相同温度下,La0.5Y0.5Ni4.8Mn0.1Al0.1和La0.5Y0.5Ni4.8Al0.2合金的PCT曲线基本重合,且都具有优良的吸氢动力学性能;相比之下,后者的滞后系数要小于前者,吸氢量较大,吸氢速率也较快,故其储氢性能较优。300次吸放氢循环实验结果表明,La0.5Y0.5Ni4.8Al0.2合金的吸氢动力学性能虽然略有下降,但抗粉化性能较好。     

Dy0.6Tb0.3Pr0.1(Fe0.95Mn0.05)x取向晶体的结构与磁致伸缩

采用Ｃｚｏｃｈｒａｌｓｋｉ方法生长了Ｄｙ０．６Ｔｂ０．３Ｐｒ０．１（Ｆｅ０．９５Ｍｎ０．０５）ｘ（１．８５≤ｘ≤１．９５）取向合金。所有合金主相为立方Ｌａｖｅｓ相结构,择优取向不完整择优取向的方向与Ｘ的大小有关。研究了沿着这些样品的生长方向的磁致伸缩性能以及磁致伸缩性能与压力之间的关系。     

Thermal Stability of Amorphous Hydride Mg_(50)Ni_(50)H_(54) and Mg_(30)Ni_(70)H_(45)

The thermal stability of amorphous ternary hydrides Mg_(50)Ni_(50)H_(54) and Mg_(30)Ni_(70)H_(45) and their corre-sponding amorphous binary alloys Mg_(50)Ni_(50) and Mg_(30)Ni_(70) were studied with X-ray diffraction(XRD) and differential scanning calorimetry(DSC). Samples of the amorphous alloys were preparedby mechanical alloying and the amorphous hydrides were obtained by charging the alloys with gas-eous hydrogen at 3.0 MPa and 423 K. It was found that the amorphous hydrides released most oftheir hydrogen before the crystallization of the essentially hydrogen depleted amorphous alloy. Thecrystallization temperature of amorphous Mg_(50)Ni_(50)H_(54) elevated and that of amorphousMg_(30)Ni_(70)H_(45) did not change in relation to the original binary amorphous alloy. This is very excep-tional for amorphous hydrides. The reason for the effects of hydrogen absorption/desorption on thecrystallization of amorphous alloys was discussed.     

Zr65Al7.5Ni10Cu15Co2.5合金的玻璃转变温度

根据Ｚｒ６５Ａｌ７。５Ｎｉ１０Ｃｕ１５Ｃｏ２。５合金的纳米晶，晶体，液体和玻璃比热的测量结果，研究了合金的玻璃转变温度与全金的热力学函数，动力学参数以及加热速度的关系。结果表明，非晶态合金玻璃转变所需转变激活能很小，玻璃转变温度实际上是由于加热速度引起的不同状态的玻璃与液体的热力学平衡温度。     

Acousto-optic interaction in alpha-BaB(2)O(4)and Li(2)B(4)O(7) crystals

Experimental studies and analysis of acousto-optic diffraction in alpha-BaB(2)O(4) and Li(2)B(4)O(7) crystals are given. Ultrasonic wave velocity, elastic compliance and stiffness coefficients, and piezo-optic and photoelastic coefficients of alpha-BaB(2)O(4) and Li(2)B(4)O(7) crystals are determined. The acousto-optic figure of merit has been estimated for different possible geometries of acousto-optic interaction. It is shown that the acousto-optic figures of merit for alpha-BaB(2)O(4) crystals reach the value M(2)=(270 +/- 70) x 10(-15) s(3)/kg for the case of interaction with the slowest ultrasonic wave. The directions of propagation and polarization of those acoustic waves are obtained on the basis of construction of acoustic slowness surfaces. The acousto-optic diffraction is experimentally studied for alpha-BaB(2)O(4) and Li(2)B(4)O(7) crystals.     

Nanomechanical characterization of one-step combustion-synthesized Al(4)B(2)O(9) and Al(18)B(4)O(33) nanowires

Two kinds of aluminum borate nanowires, Al(4)B(2)O(9) and Al(18)B(4)O(33), were successfully synthesized by a one-step combustion method through control of the Al:B atomic ratio and synthesis temperature. Both nanowires are single crystalline but have distinguishing growth habits. Nanoindentation tests were performed directly on individual nanowires to reveal their mechanical properties. A 70% reduction in elastic modulus was found in Al(18)B(4)O(33) nanowires compared with their bulk counterpart. Al(18)B(4)O(33) nanowires exhibited higher hardness and elastic modulus than Al(4)B(2)O(9) nanowires.     

Natural Passivity of Amorphous Fe_(40)Ni_(40)P_(14)B_6 and Fe_(54.6)Ni_(38)Si_(4.1)B_(2.3)V_1 Alloys

The natural passive films forrned on Fe_(40)Ni_(40)P_(14)B_6 and Fe_(54.6)Ni_(38)Si_(4.1)B_(2.3)V_1 amorphous alloys long-term exposed in air have been studied by X-ray photoelectron spectroscopy (XPS) and Auger electron (including Ar+ ion depth profiling) spectroscopy (AES). The following aspects have been investigated: (1) chemical states of the elements in the films. binding energies and the chemical shifts measured by XPSf (2) structure and composition of the films fand (3) thickness of the passive films determined by AES depth profiling and XPS analysis.     

Plasma surface treatments of poly(l-lactic acid) (PLLA) and poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV)

The surfaces of poly(l-lactic acid) (PLLA) and poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV) were modified by oxygen and nitrogen plasma treatments. The physical and chemical surface characteristics were evaluated by contact angle tests, scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). The plasma treatments caused an increase in both contact angle and roughening, altered the surface morphology, inserted polar groups, and, consequently, enhanced the hydrophilicity for both PLLA and PHBV polymers.     

Work Functions of Pd_(83.5)Si_(16.5)and Cu_(70)Ti_(30)Glassy Alloys

The work functions before and aftercrystallization of two glassy alloys,Pd_(83.5)Si_(16.5) andCu_(70)Ti_(30) have been measured by means of the con-tact potential difference method in the secondaryelectron field at room temperature under 10~(-5) Pavacuum.The results show that the work functionsof both glassy alloys are higher than those of thecorresponding crystalline alloys.