Electrochemical oxidation of isopropanol on Pt microdisc electrode

采用微电极伏安技术，研究异丙醇在PT微盘电极（rd＝10μM）上氧化的稳态和暂态的电化学行为，得出一系列重要的动力学参数：异丙醇氧化反应的反应电子数n为1.95，扩散系数d为3.22x10-5CM2/S，传递系数β值为0.12，电极体系的交换电流密度J0为3.0x10-4A/CM2，标准速度常数kS为1.60x10-4CM/S。由计算结果我们可以推测，异丙醇在PT微盘电极上酸性水溶液体系中的氧化过程由稳态传质扩散及电化学极化联合控制，其中，异丙醇分子到电极表面的扩散吸附为快速步骤，吸附的异丙醇分子在电极表面脱氢为慢步骤；异丙醇在PT微盘电极上的电化学氧化为异丙醇脱氢生成丙酮的2电子转移反应，并由此推测其可能的反应途径。The　stable　and　transient　electrochemical　behavior　of　isopropanol　oxidation　on　Pt　microdisc　electrode(rd=10μm)　were　investigated　by　voltammetric　microelectrode　technique.A　series　of　an　important　dynamic　parameters　were　obtained:n=1.95,D=3.22×10-5cm2/s,β=0.12,J0=3.0×10-4A/cm2,Ks=1.60×10-4cm/s(n——number　of　electrons　involved　in　oxidation　process;D——diffusion　coefficient;β——transfer　coefficient;J0——exchange　current　density;Ks——standard　rate　constant).From　the　results,it　can　be　considered　that　the　processes　of　isopropanol　oxidation　on　Pt　microdisc　electrode　in　the　acidic　aqueous　solution　were　simultaneously　controlled　by　steady　state　mass　transfer　diffusion　and　electrochemical　polarization.In　the　case　of　the　processes　of　isopropanol　diffuses　and　absorbs　to　the　surface　of　electrode　are　fast　step,and　the　processes　of　the　absorbed　isopropanol　dehydrogenate　on　the　surface　of　the　electrode　are　slow　step.The　results　show　that　the　main　oxidation　reaction　is　a　two　electrons　transfer　reaction　of　isopropanol　hydrogenation　to　acetone.The　probable　electrochemical　oxidation　mechanism　were　proposed

Method for Research on Performance of Intercalation of Li-ion in Carbon Materials

本文阐述了研究锂离子电池碳负极材料嵌锂行为的电化学、谱学的一般方法及所得到的一些结论,并且介绍了目前研究碳材料嵌锂行为的技术方法的进展。The electrochemistry and spectroscopy method for research on intercalation of Li -ion in carbon negative electrode for Li -ion batteries and a series of conclusions from these methods were outlined.It also introduces recent development of the techniqus in this field

Study on carbon negative electrode for lithium ion batteries

综述了目前常用的锂离子碳负极材料的研究概况，并且按碳材料的石墨化程度不同对其进行分类，具体阐述了多种锂离子电池碳负极材料的特点及其制备方法。同时还简述了锂离子在碳材料中的几种嵌入机理，综合讨论了这几种嵌入机理的优缺点。通过对碳材料的循环伏安性质、充放电性质、电容量、可逆性及结构特征的比较，介绍了不同结构的锂离子电池碳负极材料的嵌锂特性。This paper reviews the research status of all kinds of carbon materials for lithium ion batteries in the present.The properties and the producing ways of carbon materials for lithium ion batteries are described in this paper according to their graphitization degrees.By the way,it also outlines several mechanisms for lithium insertion in the carbon materials,and comprehensively discusses the excellance and problems of these mechanisms.Through comparing the variation in performance of cyclic voltammetric and charge discharge processes,the character for capacity,reversibility and structure of carbon materials with each other,it introduces the lithium intercalation characteristics in carbon anode materials for lithium ion batteries with different structure.国家自然科学基

The applied development of ferrate used as cathode materials

介绍了高铁酸盐的研究发展概况。结合高铁酸盐在水溶液体系和非水溶液体系电池中的应用,对将其作为一种新型正极材料的电化学特性进行了讨论。The recent development survey of ferrate was reviewed especially as cathode materials in batteries. The application as active materials in aqueous and non-aqueous battery system was presented. It was shown that the ferrate could be used as cathode active material in alkaline Zn/ferrate( Ⅵ), MH/ferrate(Ⅵ㈡) and lithium batteries and possessing of higher capacity than Zn/MnO? and Li/LiMn2O4 batteries respectively. However the stability of these batteries was not satisfactory due to the characteristics of ferrate. It would be key work to improve the stability of ferrate ongoing process

Recent progress of nano scale science and technology in chemical power sources

90年代纳米科学技术特别是纳米材料的应用已经扩展到化学电源领域。本文举例介绍了用于镍-碱性电池的纳米相氢氧化镍、Ab5型纳米晶态贮氢合金以及在锂离子电池中用作阴极材料的锰钡矿型MnO2纳米纤维、聚吡咯包覆尖晶石型lIMn2O4纳米管、聚吡咯/V2O5纳米复合材料，用作阳极材料的碳纳米管、纳米掺杂碳材料、纳米二氧化锡，用作固态电解质的纳米填料修饰聚氧乙烯基复合材料等几种新型纳米化学电源材料的制备、结构、形貌以及电化学性质，并且简要介绍了厦门大学化学电源研究中心纳米材料的研究进展。An increasing interest has been focused on nano scale science and technology in the field of chemical power sources.Some novel nano materials as well as synthesis methods have been prepared and designed.The synthesis methods,structure,morphological and electrochemical properties of several nano materials applied in Ni alkaline batteries and lithium ion batteries are reviewed in this papaer.The recent progress of nano materials in our chemical power sources research center is also reported.国家“863”高技术发展计划课题;中国大洋矿产资源研究开发课题;国家自然科学基金;福建省自然科学基

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

Novel cathode material for lithium ion batteries Investigation of the intercalation behavior of manganese dioxide nano fiber

采用TEM、Xrd分析等方法对新型二氧化锰纳米纤维电极材料进行表征，TEM观测结果显示这种锰材料是由许多二氧化锰纳米纤维缠绕成巢状，其纤维直径约为1nM~10nM之间；从Xrd分析表明，它是一种复合结构的锰氧化物，以钡镁锰矿为主体结构，并含有其他钠水锰矿及水羟锰矿结构。从样品电极在1MOl/llIClO4的PC-dME（1∶1）溶剂中的循环伏安曲线，可以看出在扫描的电压范围内，在3.8V和2.8V附近出现一对可逆对称的氧化还原峰，它对应于二氧化锰纳米纤维电极中锂离子的脱出-嵌入反应。通过二氧化锰纳米纤维电极在不同电流密度下的放电，可以看出该电极采用小电流放电（0.24MA/CM2），其容量可达到约190MAH/g，而且具有3V的放电平台；而在较大的电流密度（0.96MA/CM2）放电仍具有约150MAH/g的放电容量。可见，该电极具有良好的负荷特性和较高的放电容量。A novel cathode material (MnO 2) has been characterized by using transmission electron microscope (TEM) and X ray diffraction (XRD). From the TEM examination, it was found that the MnO 2 has a distinct birds nest shaped nano fiber with the diameter in the range of 1nm～10 nm. XRD data shows that the MnO 2 has a complex structure that is in the form of todorokite (3×3 tunnel) birnessite, and vernadite structure. Cyclic voltammetry has been performed in 1 mol/L LiClO 4的PC DME(1∶1) electrolyte solution. It can be seen that a pair of reversible redox peaks, which mainly occurs in the potential ranged from 2.8 to 3.8 V vs.Li/Li +, it can be described by a lithium intercalation mechanism. The galvanostatic charge discharge experiments at various current density reveal that the MnO 2 nano fiber electrodes have a high electrochemical performance and stability. The reversible capacity can reach 190 mAh/g, 150 mAh/g at lower and higher current density respectively, i.e. 0.24mA/cm 2 and 0.96mA/cm 2.国家“863”高技术发展计划课题;中国大洋矿产资源研究开发课题;国家自然科学基

EFFECT OF UNIT CELL VOLUME OF RE(Ni, Co, Mn, Ti)_5 ALLOY (RE=La, Ce, Pr, Nd) ON ITS ELECTROCHEMICAL PROPERTIES

制备了Ｌａ（Ｎｉ，Ｃｏ，Ｍｎ，Ｔｉ）５，Ｃｅ（Ｎｉ，Ｃｏ，Ｍｎ，Ｔｉ）５，Ｐｒ（Ｎｉ，Ｃｏ，Ｍｎ，Ｔｉ）５和Ｎｄ（Ｎｉ，Ｃｏ，Ｍｎ，Ｔｉ）５四种单一稀土贮氢电极合金，分别测定了它们的单胞体积、氢化物生成焓和几个主要的电化学性能指标（包括活化循环次数、最大放电容量、高倍率放电率和容量衰退速率），以分析不同稀土元素对合金电化学性能的影响.结果表明，在四种合金中，单胞体积对合金的热力学性质和电化学性能起了决定性作用，它与合金的氢化物生成焓呈简单的线性关系，对电化学性能有双重影响，使四个主要指标随单胞体积的变化均出现极大或极小值.单胞体积本身的变化与稀土元素的周期性有关．Four rare earth based AB_5 typed alloys, La(Ni, Co, Mn, Ti)5, Ce(Ni, Co, Mn, Ti)5, Pr(Ni, Co, Mn, Ti)5 and Nd(Ni, Co, Mn, Ti)5, were prepared and then their unit cell volumes (Vcell), standard enthalpies of metal hydride formation at 298 K (△H298 K), and main electrochemical characteristics, such as activation cycle number (na), maximum discharge capacity at 50 mA/g charge/discharge rate (C50,max), high-rate-dischargeability K (includes K1 and K2 ), rate of decay (-dC / dn) were measured and analyzed to reveal the effects of the rare earth elements on the electrochemical properties. The results show that the unit cell volume is the key factor in determination of the alloys' thermodynamics and electrochemical properties. The standard enthalpies of metal hydride formation at 298 K (△H298 K) are proven to vary linearly with the unit cell volume, and the four electrochemical parameters, na, C50,max, -dC/dn and K,are dualistically affected by it. The change of unit cell volume is in accord with the periodic law of the rare earth element.国家自然科学基金!59801008;; 国家863高新技术计划资助!715－004－006

Preparation and electrochemical performance of Ni-Sn alloys

[中文文摘]作为锂离子电池用非碳类负极材料,合金或金属间化合物备受关注。合金材料在循环过程中的体积变化是一个致命缺点。从抑制体积变化的角度出发,根据"BufferMatrix"的概念,将活性相植入到非活性相载体中。镍作为非活性相,锡作为活性相,用不同的方法制备了非晶态锡镍合金和晶态锡镍合金(Ni3Sn),研究了其形貌特征、晶体结构及电化学性能。在高温下用氢气还原的Ni3Sn具有稳定的晶体结构、较高的比容量(300mAh/g)和优良的循环性能。[英文文摘]As a carbon alternative anode material for Li-ion battery, alloys or inter-metal compounds were focused intensively.The alloy materials had a fatal disadvantage that the volume swelling existed during the cycles.The active materials embedded in inactive carrier based on the concept of "Buffer Matrix" to restrain the volume swellings. Ni as an inactive phase and Sn as an active phase, amorphous Ni-Sn alloy and crystalline Ni_3Sn were synthesized employing different methods which led to different morphology.The morphology characteristics , crystal structures and electrochemical performance of the materials were investigated.Ni3Sn reduced by H2 at high temperature had a stable crystal structure ,higher specific capacity (300 mAh/g) and excellent cycle performance.973项目(2002CB211804); 国家自然科学基金(20373058); 福建省科技项目(2003H044); 厦门市科技计划项目(3502Z2001234)

Recent developments in the electrolyte for LiC _6/electrolyte/cathode battery

综述现今锂离子电池电解液的研究进展 .评估了电解液中锂盐、溶剂、填加剂以及杂质等对电解液的电导、固体电解质相界面 (SEI)的形成、电池循环寿命等的影响We present a reviewed the development and status of electrolyte for LiC 6/electrolyte/cathode battery. The effect of the salt, solvent, additive and impurity on the conductivity of the electrolyte, formation of the solid_electrolyte_interphase (SEI) and cycle life of the battery were described.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 ,厦门大学宝龙电池研究所 福建厦门,361005Author's Address: State Key Lab for Phys. Chem. of Solid Surface and Dept. of Chem., Xiamen Univ.; Xiamen University and Powerlong Battery Research Institute. Inc, Department of Chemistry,