A NEW ELECTROCHEMICALLY MODULATED TIME RESOLVED UV/VIS SPECTROSCOPIC (EMTRUV/VS) TECHNIQUE AND ITS APPLICATION IN THE ELECTROCHROMISM OF POPD FILM

A new electrochemically modulated time resolved uv/vis spectroscopic(EMTRUV/VS) technique based, on optical multichannel analyzer (OMA) has been presented. EM EMTRUV/VS measurement apparatus consists of five units: an optical signal detection unit which includes a detector, a polychromator, a detector module; an optics unit; a spectroelectrochemical cell unit, which includes optical transparent electrode (OTE); an electrochemical control unit. The limit of time resolution can reach the order of an by continuously scanning mode and the order of As by gate mode which is suitable to reversible system with respect to a potential change, respectively. A high SIN ratio can be obtained by subtractive spectrum method. The electrochromism of a poly o-phenylenediamine (POPD)-coated Au OTE in aqueous 1mol . L(-1)H(2)SO(4) solution was studied by EMTRUV/VS technique.The optical absorption (lambda(max) = 550 nm)of oxidized POPE is ascribed to n ->pi* transition. The time resolved spectra acquired suggest that the oxidation reaction of PDPD occurs during the first 500 mu s and that the electrochromism is controled by H(+) transport

Progresses in the Studies on Electrochemical and Surface Properties of Hydrogen storage Alloy Materials

贮氢合金材料电化学与表面性能的研究进展①杨勇李骏林祖赓（厦门大学化学系，固体表面物理化学国家重点实验室，厦门３６１００５）八十年代后期以来，人们对地球的环境保护提出了更高的要求，而便携式电器（如移动电话，摄像机与笔记本电脑等）对电池的需求也大量增加...Recent progresses in the studies on electrochemical and surface properties of hydrogen storage alloy materials are reviewed. This paper includes three sections: 1)Thermodynamic and kinetic studies of metal hydride electrodes, 2)Effects of micro structure and alloy elements of the materials on the electrochemical properties of the electrodes and 3)Correlation between surface properties of the alloy materials and performance of the negative electrode in the nickel metal hydride batteries.作者联系地址：厦门大学化学系,固体表面物理化学国家重点实验室Author's Address: State Key Lab. for Physical Chemistry of the Solid Surface, Department of Chemistry, Xiamen University, Xiamen 361005, P.R.Chin

The Investigations of Surface Treatment Methods and Characterization of Oxide Films on AB_5based Metal Hydride Electrodes Ⅰ. New Nirich treatment methods and photoelectrochemical characterization of oxide films

发展了两种贮氢合金表面处理新方法．光电子能谱和循环伏安实验表明，经过处理后得到了富镍表面层，可提高电极的反应性能．采用光电化学方法对不同处理的电极表面由动电位氧化形成的氧化膜进行了表征，分别观察到与表面膜吸附氢氧化和氧化还原反应有关的阳极光电流和阴极光电流，同时依照电极在循环过程中的光电流变化区分了两种处理方法所得到的表面层抗氧化性能之差异．通过粉末单电极初期充放电实验，证实了电极经方法１处理以后其放电性能得到提高．Two simple and efficient surface treatment methods for AB_5type hydrogen storage alloys were developed. The results of X-ray photoelectron spectroscopy (XPS) and cyclic voltammetric (CV) experiments showed that the hydrogen storage alloys treated by two different methods had Nirich surface layer so that the performances of the electrodes were improved after treatment. The characterization of the oxide films which formed on the surface of electrodes through potentiodynamic oxidation with the help of photoelectrochemical microscopy (PEM) were done. The anodic photocurrent and the cathodic photocurrent related to the oxidation of hydrogen and the reduction of oxygen on the surface layer were observed in different potential regions respectively. Furthermore, it was found that the capability of oxidationresist of alloy depends on the surface treatment procedure, and it was shown that the capability of oxidationresist of alloy treated by the 1st method was better than the second. Finally, it was demonstrated that the discharge performance of the electrode treated by the 1st method was greatly improved.作者联系地址：厦门大学化学系固体表面物理化学国家重点实验室Author's Address: State Key Lab. for Phy. Chem. of the Solid Sur., Inst. of Phy, Chem, Dept. of Chem., Xiamen Univ., Xiamen 36100

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

Laser Scanning In-situ Photoelectrochemical MicroscopicTechnique and Its Applications

讨论了所建立的激光扫描微区光电流图谱测试系统的若干问题及其应用研究实例．实验结果表明：该测试技术是现场研究半导体及具有半导体性质的金属氧化物微区光电化学性质的有力工具，它可以在微米水平上提供许多有关半导体／电解质溶液界面的结构和电子性质方面的重要信息．Abstract The main factors of the laser scanning in-situ photoelectrochemical microscopicmeasurement system which is set up in our lab have been discusaed in this paper. Some applications ofthis technique for insttn study of medificiition and processing of semiconductor electrodes , monitoringof electredeposition process of semiconducting material and redox reaction occurring at metal oxideelectrodes have aiso been presented. The results have shown that the technique is very powerfui thatfor studing local photoelectrochemical properties of semiconductors and metal oxide electredes. Theseprovide important information on the micro structural and electronic properties in the solidlelectrolyteinterface.AbstractLaser scanning, Local photocurrent spectroscopy, Photoelectrochemical,Semiconductor electode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，化学系Author's Address: State Key Lab.for Phy. Chem.of the Solid Surface,Dept. of Chem.,Xiamen Univ.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

A Novel Reaction region Moving Electrode System for Electrochemical Power Sources

本文提出一种适于高速充电的新型化学电源电极，该电极体系在充电时，反应界面能迅速推移，使活性物质能迅速沉积在三维载体电极上，特别适用于强电流高速充电．充电时活性物质以固态沉积在电极表面，而放电时活性物质又溶解为液态．电极体系在充放电循环过程中活性物质是以固（ 态）＿液（ 态） 循环形式进行循环，因而可以保持新鲜的电极表面，防止固体电极表面活性物质的相变、钝化、脱落、变形等弊端，有利于延长电极的寿命．该电极体系可望在大电流快速充电的动力电源上获得应用In most of practical rechargeable batteries, charging/discharging process is always concerned with phase_transformation in the solid state. Due to the irreversibility of the phase_transformation, the cyclic performance of the rechargeable batteries are limited. In this paper, a novel reaction_region moving counter electrode system is constructed in our laboratory. The electrode system is operated at room temperature and cycled in solid_liquid phase during charging/discharging processes. With this electrode, the metal_complexes are firstly deposited(i.e. charging process) on the nearest working electrode and gradually extended to those another working electrodes several centimeters away from the counter electrode. The deposite is dissolved again into the solution during discharge process. Owing to the movement of the reaction_region, the electrode system can be used to produce high surface area electrodes and it can also be charged at high current, which has been used to design high energy_density rechargeable batteries in our group.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!物理化学研究所厦门大学化学电源研究中心厦门361005,厦门大学固体表面物理化学国家重点实验室!物理化学研究所厦门大学化学电源研究中心厦门361005,厦门大学固体表面物理化学国家重点实验室!物理化学研究所厦门大学化学电源研究中心厦Author's Address: State Key Lab. for Phy. Chem. of the Solid Surface, Phys. Chem. Inst., Research Center for Electrochemical Power Sources, Xiamen Univ., Xiamen 36100

The Study of the Growth Processes of the Oxides on Lead Electrodes in Sulfuric Acid Solution

采用实时交流阻抗测量与激光扫描微区光电流技术相结合的现场方法，对铅电极在硫酸溶液中ＰｂＯ和ＰｂＯ＿２的生长过程进行了研究．发现电极在ＰｂＯ的形成区中氧化５ｍｉｎ后，电极欧姆阻抗和ｔ￣（１／２）呈一直线关系，这表明ＰｂＯ是均匀分布在电极表面而成长的．激光扫描微区光电流的实验进一步证实了这一结论．实验中还发现ＰｂＯ＿２在ＰｂＯ层中是局部发生与发展的．The growth processes of PbO and PbO_2 on lead electrodes have been investigatedby using in-situ methods that are combined with temporary AC resistance measurment technique andin-situ laser scanning photoelectrochemical microscopy.It is found that a linear relationship existsbetween the electrode resistance(R)and￣(1/2) after the electrode is oxidized at +0.6 V(vs.Hg/H_2SO_4/35%H_2SO_4)for more than 5 min.This result suggests that the growth of PbO is well distributedduring the early stage of oxidation.The study by using laser scanning photoelectrochemical microscopyhas further proved this point.The results also show that the growth of PbO_2 takes place and develops.作者联系地址：厦门大学化学系Author's Address: State Key Laboratory for Physical Chemistry of the solid Surface,Department of Chemistry,Xiamen University,Xiamen 36100

Study on Nano Electrode Material of Lithium Ion Batteries

采用ＸＲＤ、ＴＥＭ方法对纳米相电极材料的结构、形貌进行表征，并用循环伏安法、恒流充放电法对电极材料的嵌锂电化学行为进行研究．结果表明，由于纳米材料的微结构特性使其具有优越的嵌锂特性：１）锂离子嵌入电极材料内部的深度小，过程短，具有较大的比表面，有利于采用较大的电流对该电池进行充放电．２）具有较大的嵌锂空间位置，有利于增加电极的锂嵌容量．In this paper, the structure and morphology of the nano phase electrode materials have been characterized with XRD and TEM. The performances of electrochemical intercalation and deintercalation of lithium ions have been studied by using cyclic voltammograms and galvanostatic charge discharge techniques. The results show that the nano materials posses advantage of micro structure and Li+ ions intercalation performances. The observed high capacity and large charge discharge current density of the nano phase materials seem to have resulted from three kinds of effects: 1) an increase in the space for Li+ ions intercalation; 2) a decrease in the distance for Li+ ions to diffuse through the solid phase; 3) a decrease in real current density of high specific surface area at nano phase materials.作者联系地址：厦门大学化学系物理化学研究所固体表面物理化学国家重点实验室Author's Address: State key Lab. for Phys. Chem. of Solid Surf., Dept. of Chem., Inst. of Phys. Chem.,Xiamen University, Xiamen 36100