LSC包覆改性LiFePO_4/C锂电池正极材料特性研究

采用酒精悬浮液法对商用LiFePO4/C进行了La0.6Sr0.4Co O3-δ(LSC)包覆改性,LSC包覆量为1%~5%(质量分数),通过充放电测试、电化学阻抗测试考察了不同包覆配比对材料高倍率放电比容量和循环性能的影响。结果表明,适当含量LSC包覆可提高LiFePO4电池高倍率放电比容量和循环性能,以4%(质量分数)LSC包覆改性的LiFePO4/C作为蓄电池正极材料时,2 C充放电时比容量较改性前提高22%,55次充放电循环后容量损失率减小22.1%,以其替代LiFePO4/C可增大蓄电池容量,延长蓄电池组使用寿命,具有良好的应用前景。     

蓄电池添加剂 Co、CoO、Co(OH)_2 的研究现状

Ｃｏ及其化合物ＣｏＯ、Ｃｏ（ＯＨ）２是近年来被用于充电添加剂的高新技术材料。能提高电池的比能量和输出功率,延长充放电循环使用寿命,减少自放电现象等,使电池性能得到明显改善。本文较全面地总结了三种物质的制备方法和物理化学性质,并指出了每种方法的特点;阐明了它们在蓄电池中的作用机制;介绍了它们在国内外的生产、开发状况及应用、发展动向。     

Anchoring CoP nanoparticles on the octahedral CoO by self-phosphating for enhanced photocatalytic overall water splitting activity under visible light

Designing an effective and stable composite photocatalyst is of significance for the further realization of practical applications. In this study, a series of CoP/CoO composites are successfully prepared by a straight one-step phosphating method. The reasonable design and controllable preparation of CoP/CoO composite make it exhibit improved photocatalytic performance for overall water splitting and excellent stability under visible light irradiation in comparison with pure CoO, which is derived from the CoP nanoparticles well dispersed on the (111) facets of CoO octahedrons, intimate interface between them and efficiently accelerated of photo-induced electrons from CoO to CoP. This study presents a simple method to design highly-effective composite photocatalysts for overall water splitting to meet the energy demand.     

溶胶-凝胶法制备La0.8Sr0.2CoO3纳米材料

以La(NO3)3·6H2O、Sr(NO3)2、Co(NO3)2·6H2O为原料,用EDTA络合溶胶-凝胶法制备La0.8Sr0.2CoO3凝胶,在700℃、800℃、900℃煅烧,制得La0.8Sr0.2CoO3粉体.用DTA、FT-IR、XRD、SEM等手段对制备过程、热分解机理及粉体的性能进行了研究.在700℃焙烧2 h得到La0.8Sr0.2CoO3纯相纳米粉,颗粒呈球形.选取700℃焙烧2 h的La0.8Sr0.2CoO3粉体制成管状传感器,进行NO2敏感性能测试,探讨了相同NO2浓度下,传感器敏感信号与温度的关系.结果表明:纳米La0.8Sr0.2CoO3粉体在450℃时对NO2的敏感信号最大,输出的电动势信号与NO2浓度之间呈线性关系.     

单分散性Fe_3O_4/CoO/SiO_2复合纳米粒子的制备与表征

采用溶剂热法,在160℃下,以聚乙烯吡咯烷酮(PVP)为表面活性剂,制备Fe3O4/CoO复合纳米粒子;然后采用St觟ber法,在35℃下,以氨水催化正硅酸乙酯(TEOS),制备Fe3O4/CoO/SiO2复合纳米粒子。考察反应物配比、氨水浓度、醇水比对Fe3O4/CoO/SiO2复合粒子磁学性能的影响。对复合纳米粒子采用X射线衍射(XRD)、透射电子显微镜(TEM)、交流梯度磁强计(VSM)、差热分析(DTA)等手段进行表征分析。结果表明:Fe3O4/CoO/SiO2复合纳米粒子晶形生长良好,粒径在20nm左右。利用CoO进行表面修饰后,提高了纳米Fe3O4粒子的饱和磁化强度,通过包覆SiO2进行表面改性后,提高了纳米Fe3O4粒子的分散性和稳定性。实验确定了Fe3O4/CoO复合粒子与TEOS的摩尔比1∶2、TEOS与氨水的摩尔比1∶3、无水乙醇与蒸馏水的体积比2∶1为最佳反应物配比。     

溶剂热法合成纳米级CoO粉体及其生长习性

以四水醋酸钴和无水乙醇为原料,采用溶剂热法在150℃制备了纳米晶体CoO. 利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)和透射电子显微镜(TEM)等手段对产物进行了分析和表征. 结果表明,产物CoO晶体为面心立方结构,晶粒尺寸约为50 nm,大小均匀,分散性好. 研究了不同合成条件对CoO晶粒尺寸的影响,并分析了CoO的结晶习性,在低过饱和度条件下,CoO晶体因{111}晶面生长速度最慢而显露,因此它的形貌为八面体     

Pd/γ-Al2O3催化剂上甲烷-氘化氢之间的氢氘交换性能研究

通过M-T、M-H曲线的测量,研究Dy掺入对La0.7Sr0.3CoO3体系磁性的影响.结果表明,随着Dy含量的增加,样品Tc降低、M值减弱、矫顽力增强,并出现低温下M随着T的降低继续增大的反常现象.研究表明,体系磁性的变化来源于Dy掺入引起晶格参数的改变和磁环境的改变,以及Dy离子诱导的Co离子自旋态的转变.     

Substituting Effect of Y in La0.5Ba0.5 CoO3

La0.5-xYxBa0.5CoO3 polycrystals were prepared by solid state reaction. The substituting effects of Y for La on the magnetic and transport properties of the materials were studied systematically. The results indicate that substitution of Y induces two effects. Firstly, the charge transfer from Y to 3d orbital of Co happens. This causes the molecular magnetic moment to decrease. Secondly, the antiferromagnetic exchange interaction of Co ions appears. When the content of Y is less than or equal to 30%, the non-colinear structure of spins in materials is observed. When the content of Y is greater than 30%, the materials transit from predominant ferromagnetic state to predominant antiferromagnetic one. The conductive mechanism for the materials with different content of Y belongs to the variable range hopping conduction of polarons.The resistivity of materials increases sharply with increasing Y content.     

La0.5Ba0.5CoO3中的Pr掺杂效应

用固相反应法制备了La0.5-xPrxBa0.5CoO3系列化合物，系统研究了Pr不同含量时材料的磁性和电输运特性，结果表明：Pr掺杂没有改变Co的3d电子的巡游特性。随Pr掺杂量增加，材料的分子磁矩单调下降，其原因是当Pr逐渐取代La时，Co离子的3d电子逐渐由中间自旋态向低自放态转变。随Pr含量增加，材料的居里温度逐渐下降，这是由于稀土离子的尺寸效应，电阻测量表明：在所研究的温度范围内，居里温度以下，所有掺Pr材料的导电机制为热扩散型。居里点以上，导电机制为变程跳跃导电。     

Removal of NOx and Diesel Soot Particulates Catalyzed by Perovskite-type Oxide La0.9K0.1CoO3

1 IntroductionTeraoka and Shangguan,etchaveresearchedthereac-tion between tight soot and catalyst mixture with tempera-ture increase[1-5].Their results confirmedthat the La0 .9K0 .1CoO3perovskite type composite oxide are excellent catalystwhich can simultaneously remove diesel particulate matterand NOx[3 ,4].We have researchedthetraditional solidstatereaction method and sol-gel methodfor preparation of La0 .9K0 .1CoO3perovskite composite oxide[6].The results showsthat for boththe method t…