Electrochemical Impedance Spectroscopic Studies of the First Lithiation of Si/C Composite Electrode

采用球磨法制备了SI/C复合材料,X射线衍射(Xrd)和扫描电子显微镜(SEM)测试结果显示SI/C复合材料中硅保持着良好的晶体结构且均匀的分散于炭黑基体中.充放电测试结果表明SI/C复合材料首次放电容量高达3393 MAH/g,4周之后可逆容量均保持在1000 MAH/g左右,表现出较好的循环性能.电化学阻抗谱测试结果显示,SI/C复合材料电极在首次嵌锂过程中分别出现了代表接触阻抗、固体电解质相界面界面膜(SEI膜)阻抗、电荷传递阻抗和相变阻抗的圆弧,并详细分析了它们的变化规律.The Si/C composite materials were prepared by ball milling method,and characterized by X-ray diffraction(XRD) and scanning electron microscopy(SEM).The result displayed that Si in the Si/C com-posite materials still maintained a good crystal structure and uniformly dispersed in carbon black matrix.The first discharge capacity was 3393 mAh/g,and 4 cycles later still retained 1000 mAh/g,showing better charge-discharge cycle performance.Electrochemical impedance spectroscopy test indicated that there ap-peared three semicircles respectively representing the impedance of contact problems,solid electrolyte in-terface film(SEI film),charge transfer and phase transformation in the first lithiation,and their evolutive principles were also investigated.中央高校基本科研业务费专项资金(Nos.2010LKHX03;2010QNB04;2010QNB05);中国矿业大学科技攀登计划(No.ON090237);江苏省普通高校研究生科研创新计划(No.CX10B_153Z)资助项

Electrochemical Impedance Spectroscopic Studies of the First Lithiation of Si/C Composite Electrode

The Si/C composite materials were prepared by ball milling method, and characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The result displayed that Si in the Si/C composite materials still maintained a good crystal structure and uniformly dispersed in carbon black matrix. The first discharge capacity was 3393 mAh/g, and 4 cycles later still retained 1000 mAh/g, showing better charge-discharge cycle performance. Electrochemical impedance spectroscopy test indicated that there appeare three semicircles respectively representing the impedance of contact problems, solid electrolyte interface film (SEI film), charge transfer and phase transformation in the first lithiation, and their evolutive principles were also investigated

ZrB2对烧结Sm(Co0.717Fe0.15Cu0.10Zr0.033)7.2合金微观组织和性能的影响

通过在制粉阶段添加微量ZrB2粉末的方法，制备了Sm(Co0.717Fe0.15Cu0.10Zr0.033)7.2 (ZrB2)x ( x=0～0.025)烧结磁体。采用扫描电子显微镜、能谱分析和x射线衍射分析磁体的微观组织及相组成，利用NIM-2000型直流磁性测量仪测试磁体的磁性能，研究了添加ZrB2对永磁体组织性能的影响。结果表明：适量添加ZrB2可以降低磁体的烧结温度；ZrB2发生部分分解会影响合金组织与结构，使合金室温磁性能和高温稳定性都有不同程度的提高；没有分解的ZrB2颗粒以质点的形式存在，使磁体的断裂韧性值大幅度增加

一种钐钴系烧结磁体材料及其制备方法

本发明公开了一种2:17型钐钴系烧结磁体材料及其制备方法，该2:17型钐钴系磁体材料由钐、钴、铁、铜、锆以及至少一种重稀土元素组成，以质量百分比计，钐占10～25％，钴占45～55％，铁占10～20％，铜占3～9％，锆占1～3％，重稀土元素占5～15％。本发明通过原料的选取与配比，以及烧结工艺上的创新，最大程度地优化了磁体材料的微观组织结构，达到降低磁体的温度系数，同时保持较高磁体磁能积的目的，制备得到的磁体的磁能积为14～25MGsOe，剩磁温度系数约为-0.005～-0.03％/℃，能在-35℃～300℃的环境中保持较低的磁通温度系数

高稳定性钴基永磁体、其制备方法及调控方法

本发明提供了一种高稳定性钴基永磁体、其制备方法及调控方法。所述永磁体主要由Co、Ni、Al、Ti、Cu、Fe及Nb等元素组成，所述永磁体具有周期调幅的纳米双相结构，所述纳米双相结构由结晶状均为立方结构的富FeCo析出相和富AlNi基体相组成，并且Nb元素在富AlNi基体相中偏聚分布。进一步的，所述富FeCo析出相具有细长棒状结构，并周期弥散分布在所述的富AlNi基体相中，且所述富FeCo析出相的轴向与所述柱状晶的轴向平行。本发明在所述永磁体的制备中通过严格控制定向凝固和热处理工艺，调节Co及Nb元素含量而调整磁体相结构、形貌及析出相的磁特性，从而调控磁体剩磁温度稳定性，得到剩磁随温度升高线性降低，且温度系数优于万分之一的高稳定性钴基永磁体