Electrochemical intercalation performances of new cathode materials——Manganese nodule for lithium ion rechargeable batteries

研究了天然锰结核作为锂离子蓄电池阴极材料的可行性 ,从其组成结构与电化学嵌锂行为作了广泛全面的研究和评价。研究结果表明 ,锰结核的电化学性质是由钡镁锰矿和水羟锰矿加和的结果 ;锰结核的锂离子嵌入脱出电位在 2 .6V和 3V附近 ,在 2 .5～ 4.1V之间充放电 2 0 0多次后 ,放电容量降至约 10 1mA/ g ,保持率为 92 .5 % ,具有较好的充放电可逆性能 ,表明层状结构的钠水锰矿和水羟锰矿是一种良好的锂离子嵌入脱出电极材料 ,它是一种具有应用前景的新型锂电池和锂离子电池阴极材料。A comprehensive research and evaluation for manganese nodule as cathode material for lithium ion batteries was made. The composition, structure and micro-morphology, the electrochemical properties and the optimization of its charge/discharge performance were studied. The interstitial multi-metallic cations in tunnels and interlayers, such as Mg 2+ ,Ni 2+ ,Co 2+ ,Ca 2+ ,Cu 2+ ,etc.,and the lattice water contributed to equalization of chemical valence and structural stabilization of manganese nodule.The results show that the electrochemical properties of manganese nodule are attributed to Todorokite and Vernadite. In a appropriate electrolyte, such as LiClO 4/PC+DME, and the electrolyte of avoiding over-intercalating, the lattice water may not be harmful to the electrochemical performance. The Li insertion and extraction potentials of manganese nodule are about 2.6 V and 3 V, respectively. The cyclic voltammetry curves show that the broad current peaks reflect the characteristics of amorphous state of manganese nodule. Manganese nodule shows a good reversible discharge capacity (101 mAh·g -1 , 85% of the highest discharge capacity) at about 2.5-4.1 V after more than 200 cycles in 1mol/L LiClO 4/PC+DME. It is proved that manganese nodule is a promising novel natural cathode material for lithium ion batteries.中国大洋矿产资源研究开发资助课题! (DY 95 0 4 0 6

Rapid Determination of Ni￣(2+), Fe￣(2+)and Cl-Ions Concentration in Ni and Ni-Fe Plating Baths

根据nI2＋在汞膜电极上的电化学还原和fE2＋、Cl在铂电极上的电化学氧化特性，采用dz-lb型电镀添加剂测定仪快速测定镍和镍铁镀液中nI2＋、fE2＋和Cl-的浓度。操作简便，快速，适用于电镀车间的镀液分析

Applications of fluorescence analysis methods in the analysis of environmental organic pollutants

综述了近年来荧光分析法在环境有机污染物分析中的应用,主要介绍了国内的应用情况。内容包括:常规荧光分析法、同步荧光光谱法、导数荧光光谱法、三维荧光光谱法、固体表面荧光光谱法和荧光动力学分析法等,共引用参考文献113篇。The applications of fluorescence analysis methods in the analysis of environmental organic pollutants in recent years are reviewed with 113 references, with the emphasis being domestic applications. The methods include conventional fluorescence analysis, sychronous fluorescence spectrometry, derivative fluorescence spectrometry, 3-D fluorescence spectrometry, solid surface fluorescence spectrometry and fluorescence dynamic analysis

Structural and Electrochemical Studies on Lithium Manganese Oxide Containing Li + Prepared by Hydrothermal Method for Lithium Ion Batteries

利 用 Ｘ Ｒ Ｄ、 Ｉ Ｃ Ｐ、 Ｔ Ｇ Ａ 、 Ｄ Ｔ Ａ 及 恒 流 充 放 电 等 方 法 研 究 分 析 了 一 种 特 殊 天 然 结 构 Ｍｎ Ｏ２（ Ｎ Ｍ Ｄ） 材料的结 构、组成 以及电 化学嵌锂 特性． Ｘ Ｒ Ｄ 分析 表明，该样 品材料 是由钠水 锰矿以及水羟 锰矿复 合结构组 成的 Ｍｎ Ｏ２ 纳米 纤 维． 充放 电 循环 结果 显 示，其 前 期循 环容 量 可高 达 １５０ｍ Ａｈ／ ｇ 左 右，但性 能尚不够 稳定． 本文采 用一种 水热法高 压嵌锂处 理，可将 Ｎ Ｍ Ｄ 样品 转变为 具有３ ×３ 大隧道结 构的钡 镁锰矿（ Ｔｏｄｏｒｏｋｉｔｅ） 型锂 锰氧 化 物，既 增 强了 Ｌｉ ＋ 嵌 入 隧道 或 层间 结 构 的循环稳定 性． 并 显著提 高锂锰氧 化物电 极材料性 能的 稳定 性，以 充放 电电 流密 度 为０ ．８ ｍ Ａ／ｃ ｍ ２ ，经过１８０ 次 循环后 其比容量 仍具有 １１０ ｍ Ａｈ／ ｇ ． 该类 大隧道结 构锂锰 氧化物可 作为一 种３ Ｖ 的锂离子电极 材料．In this paper, Todorokite manganese oxides containing Li + with large tunnel structure(sample M5) have been synthesized by hydrothermal methods from natural manganese oxide nano fiber (sample M4). The structure and composition of the samples were characterized and analyzed by XRD, ICP, TGA and DTA. Its electrochemical behavior as a cathode materials for rechargeable lithium ion insertion were studied by galvanostatic charge/discharge measurements. XRD results show that the sample M4 is mainly composed of Birnessite and Vernadite structure. Although the sample M4 shows a high initial capacity of approximately 150 mAh/g, its performances decrease gradually over 30 cycles. It is found that the materials have highly reversible charge/discharge cycling performances after being converted into Todorokite lithium manganese oxide(sample M5). This sample exhibit a single reduction step centered at Ca. 2.8 V and its discharge capacity maintains about 110 mAh/g after 180 cycles at current density of 0.8 mA/cm 2. The novel lithium manganese oxide with a large tunnel structure can be used as 3V cathode material of lithium ion batteries.作者联系地址：厦门大学固体表面物理化学国家重点实验室!厦门大学物理化学研究所化学系厦门361005,厦门大学固体表面物理化学国家重点实验室!厦门大学物理化学研究所化学系厦门361005,厦门大学固体表面物理化学国家重点实验室!厦门大学物理化学研究所化学系厦门361005,厦门大学固体表面物理Author's Address: State Key Lab. for Phys. Chem. of Solid Surf., Inst. of Phys. Chem., Dept. of Chem., Xiamen Univ., Xiamen, 36100

Structural and Electrochemical Studies on Todorokite/Vernadite as Cathodes for Rechargeable Lithium Ion Batteries

利用ＸＲＤ、ＴＥＭ、ＩＣＰ、低速ＣＶ以及恒流充放电等方法研究了一种３Ｖ锂离子电池阴极材料的结构及其电化学性能．样品主要由大隧道型结构的钡镁锰矿和层状结构的水羟锰矿组成，该样品的微观形貌为层间距约１０ｎｍ的叠片状结构．Ｌｉ＋在样品中的嵌入脱出过程具有较好的可逆性和循环稳定性．未经提纯的样品前３０次循环的放电比容量达到１２９ｍＡｈ／ｇ，１００次循环后为９６ｍＡｈ／ｇ．材料结构中嵌入隧道及层间的杂质金属阳离子起着结构支撑以及维持材料的微观结构和电化学性能稳定性的作用．XRD,TEM,ICP,low scan_rate CV and charge/discharge tests were carried out for the studies on the structural and electrochemical behavior of a prepared 3 V manganese oxide cathode for rechargeable lithium ion batteries.XRD analysis revealed that the cathode sample is mainly composed of tunneled Todorokite and layered Vernadite.TEM investigation confirmed that the morphology of the sample is a laminated construction with approximate 10nm layer space.The reversibility of Li + removal/intercalation and structural stability of this sample framework to lithium insertion are good in CV and charge/discharge tests. The discharge capacities were found to be about 129mAh/g obtained on first 30 cycles and remained to be 96mAh/g after 100 charge/discharge cycles.The inlaid cations in the tunnel or interlayer made contribution to the structural and electrochemical stability of this manganese oxide cathode framework.作者联系地址：厦门大学固体表面物理化学国家重点实验室Author's Address: State Key Laboratory for Physical Chemistry of Solid Surface, Inst. of Phys. Chem.,Dept.of Chem.,Xiamen Univ.,Xiamen 36100

蓝紫光InGaN多量子阱激光器

在（0001）蓝宝石衬底上外延生长了InGaN长周期多量子阱激光器结构．三轴晶X射线衍射测量显示该多量子阱结构质量优良．用该外延片制作了脊形波导GaN激光器，激光器的腔面为GaN的自然解理面，室温，电脉冲注入，激光器可实现激射．阈值电流密度为3．3kA／cm~2，特征温度为145K