无机超细粉体改性锂离子电池隔膜的研究进展

综述了近年来无机超细粉体改性锂离子电池隔膜的研究进展,首先介绍了已在锂电隔膜改性上商业应用的Al₂O₃和AlOOH对传统聚烯烃膜和新型静电纺丝膜的改性方法和改性效果,随后又对常规无机材料TiO₂和SiO₂粉体对锂电隔膜的改性进行了叙述,最后对BN等非常规隔膜改性无机材料进行了简介;总结和讨论了无机材料改性后隔膜的组分、结构和性能对锂离子电池综合性能的影响,并对其无机材料改性锂电池隔膜的未来发展趋势进行了展望。     

化学交联聚酰亚胺隔膜增强锂离子电池性能研究

隔膜作为锂离子电池的重要组成部分,用于阻隔阴极和阳极直接接触,同时为锂离子在电极间的传输提供有效通道。聚酰亚胺隔膜因其具有充放电循环寿命长、机械强度适中、良好的电绝缘性能以及自熄能力等优点,而受到广泛关注。以对苯二甲胺作为交联剂,将聚酰亚胺隔膜进行化学交联,研究了交联时间与隔膜形貌、结构及性能之间的构效关系。随着交联时间的增加,隔膜的孔隙率和吸液率逐渐降低,电解液接触角和机械强度逐渐增大。电化学测试表明,随着交联时间的增加,隔膜的本体阻抗逐渐增大,进而离子电导率逐渐降低,而交联隔膜的界面阻抗均远小于未交联隔膜,且交联隔膜的电化学窗口也均大于未交联隔膜。通过组装半电池测试发现,交联隔膜所组装电池的倍率性能和循环性能均优于未交联隔膜,当交联时间为48 h时,电池性能表现最优,循环100次以后,放电比容量为130.2 mA·h/g,容量保留率为91.1%。     

机械活化-湿化学合成LiMn2O4的组成、结构与表征

以MnO2和LiOH·H2O为原料,采用机械活化与湿化学集成的方法,在水溶液中直接合成了结晶态的尖晶石锂锰氧化物.当锂含量介于3.78%～4.35%之间时,所得锂锰氧化物为纳米级球形粉末,以尖晶石结构为主,含极少量的Mn3O4杂相;在300～800℃温度范围内热处理后,Mn3O4杂相消失,尖晶石结构更趋完善.所合成的含锂5.80%的高锂样品则以LiMnO2层状结构为主,含少量Mn3O4杂相,其SEM形貌为片状;在300～700℃下热处理8 h后,层状LiMnO2转变成尖晶石LiMn2O4,Mn3O4杂相峰明显减弱并随热处理温度的升高而消失;当温度升高至700～800℃时,开始出现缺锂的Li1-xMn2O4相.结果表明:该法制备锂锰氧化物可实现锂、锰、氧在原子级水平的均匀混合,所得产物的热稳定性能良好,其化学计量组成与结构易于调整和控制.     

1Cr18Ni9Ti不锈钢氮离子注入层超显微硬度的研究

应用超显微硬度计测定１Ｃｒ１８Ｎｉ９Ｔｉ奥氏体不锈钢氮离子注入层的硬度，并用Ａｕｇｅｒ电子能谱仪（ＡＥＳ）及高精度轮廓仪测定氮离子注入层氮浓度分布及深度．结果表明：在９０ｋｅＶ，３ｘ１０~１７Ｎ＋／ｃｍ~２注入时．共注入层深度为０．１８μｍ、用１ｍＮ载荷侧得本征硬度ＨＶ为３．４７ＧＰａ，比非注入态表面硬度提高三倍之多，合理的试验载荷应≤ｌｍＮ（０．１ｇ）．     

强流脉冲离子束表面再制造技术原理与应用

采用TEMP-6型强流脉冲离子束(HIPIB)装置开展了HIPIB表面再制造技术的研发.HIPIB装置主体由高压脉冲电源系统和高功率离子二极管系统组成,通过高压短脉冲在二极管中放电产生阳极等离子体并引出ns级强流离子束.HIPIB辐照材料表面,发生显著的熔融、蒸发和剧烈烧蚀,物质喷射的反冲作用在辐照表面形成由表及里的应力波,导致材料表层强烈的热-力学效应.利用HIPIB与材料表面的相互作用,应用于涡轮叶片表面的清洗维修,可有效去除涡轮叶片基体因高温氧化形成的氧化物,伴随表层的重熔将叶片基体表面微观缺陷焊合,获得了光滑、平整的涡轮叶片修复表面.实现了HIPIB辐照在涡轮叶片表面再制造方面的应用.     

Synergistic inhibition between o-phenanthroline and chloride ion for steel corrosion in sulphuric acid

The corrosion inhibition of cold rolled steel in 0.5 M sulphuric acid in the presence of o-phenanthroline and sodium chloride (NaCl) has been investigated by using weight loss and electrochemical techniques. The experimental data suggest that the inhibition efficiency increases with increasing NaCl concentration in the presence of 0.0002 M o-phenanthroline, but decreases with increasing temperature. A synergistic effect is observed when o-phenanthroline and chloride ions are used together to prevent cold rolled steel corrosion in 0.5 M sulphuric acid. The polarization curves showed that the complex of o-phenanthroline and NaCl acts as a mixed type inhibitor. The experimental results suggested that the presence of chloride ions in the solution stabilized the adsorption of o-phenanthroline molecules on the metal surface and improved the inhibition efficiency of o-phenanthroline. The adsorption of the complex accords with the Langmuir adsorption isotherm. Some thermodynamic parameters such as adsorption heat, adsorption entropy and adsorption free energy have been calculated by employing thermodynamic equations. Kinetic parameters such as apparent activation energy and pre-exponential factor have been calculated and discussed.     

CRYSTAL STRUCTURE OF γ-Li_xFe_2O_3 WITH ELECTROCHEMICAL INSERTION OF Li

Crystal structure of γ-Li_xFe_2O_3,inserted Li electrochemically,was studied by Moss-bauer spectroscopy together with X-ray diffraction,XPS and electrochemical method,Onthe insertion of Li at low current density,the crystal structure is keeping original spinel;while at higher current density or by thermal activation,owing to violent movement ofLi~+ ions,part of crystal structure transforms into rock type similar to face-centeredcubic structure of ferrous oxide.The transition channels during insertion of Li~+ ions andlimitation of Li~+ ions inserted were discussed.     

Kinetics of synthesis of Li4Ti5O12 through solid-solid reaction

1. Introduction The solid-solid reaction used in synthesizing various kinds of electrochemical materials has many advantages, such as simple process, without using solvent, saving energy, friendly to the environment and easy to obtain good quality materials like nano-size materials. Recently, the manufacturing of electrochemistry materials has been paid more atten- tion due to its increasing needs. Therefore it is a natural interest to study the synthesis of electro- chemical materials by usin…     

Dose and dose rate effects on coherent-to-incoherent transition of precipitates upon irradiation

A typical precipitation hardened alloy, Cu-Co dilute alloy was selected to study the precipitation behavior and irradiation effect on precipitates. It is found that the principal effect of ion irradiation on the coherent precipitates is loss of coherency, and TEM cross-section observations show that the fraction of the incoherent precipitates is dependent on dose but not on dose rate during heavy ion irradiation.