Electrochemical property of spinel LiMn_2O_4 prepared by sol-gel method

利用循环伏安法 (CV )、恒流充放电、电化学阻抗谱 (EIS)等电化学手段研究了溶胶凝胶法制备的尖晶石型LiMn2 O4 的电化学性质。结果表明用溶胶凝胶法制备的样品放电容量大 ,可逆性好 ,其中 5 5 0℃煅烧的样品电化学性能最好 ;XRD结果表明 ,样品经过充放电 ,尖晶石结构仍保留 ,但出现深度放电产物Li2 Mn2 O4 。The electrochemical properties of spinel LiMn 2O 4 electrodes prepared by a sol gel method were studied by cyclic voltammetry, constant current charge discharge and electrochemical impedance spectrum(EIS) techniques. The experimental results showed that the electrochemical performance of the samples prepared by sol gel method was better than that of the sample prepared by normal method. The electrochemical performance of the sample prepared by sol gel method at 550℃ showed the best electrochemical performance. After constant current charge discharge the spinel structures in all samples were reserved and deeply discharging product Li 2Mn 2O 4 was detected from XRD results.国家自然科学基金 ( 2 98330 90 );; “86 3”高技术发展计划 ( 715 -0 0 4-0 2 5 0

Investigation of lithium manganese oxides with large tunnel structure as electrode material in Li ion batteries

锂锰氧化物材料是一类重要的锂离子电池电极材料。文中报道一种新型大隧道结构镁锰复合氧化物〔结构类型：钡镁锰矿（TOdOrOkITE）型〕的合成方法及其电化学性能表征。X-光衍射（Xrd）谱证实了合成物具有所预想的（3x3）隧道结构。在慢速循环伏安图中可发现该类电极材料分别在3.35V及2.45V（VS.lI）出现一对锂离子的脱出-嵌入峰。充放电实验结果表明：该类大隧道结构复合氧化物可作为一种3V锂离子电池的电极材料，当充放电电流密度为0.1MA/CM2时，材料的初次容量可达158MAg/H，经过4次充放电循环后其容量仍可保持在约130MAH/g。Lithium manganese oxide is one kind of the important electrode material of Li ion batteries.In this paper, investigations of a novel Li Mn oxide electrode material with large tunnel structure such as todorokite type electode material For Li ion batteries are carried out in the lab.It is demonstrated that the material synthesized has a todo rokite structure (i.e.3×3 tunnel)using X ray diFFraction(XRD) method.It is also observed that a couple of deintercalation/intercalation peaks of lithium ion appear at 3.35V and 2.46V (vs.Li) respectively in the slow rate cyclic voltammograms.In addition,it is Found that the material shows quite good cyclic perFormance,the initial capacity of the material is 158mAh/g,and its discharge capacity is still kept at about 130mAh/g aFter Four cycles at charging/discharging current density of 0.1mA/cm 2.福建省自然科学基金;杰出青年基

The Effect of Suspended Particles on the Corrosion Resistance of Electrodeposited Zinc Powders

在ＺｎＣｌ２镀槽中悬浮一定量的不溶性粒子，如石墨，ＰｂＯ２，ＳｎＯ２，ＴｉＯ２，ＳｉＯ２等，电沉积制备Ｚｎ粉，并对其结构、形貌及腐蚀行为进行分析．ＳＥＭ的结果表明使用悬浮法可阻止Ｚｎ枝晶生长．悬浮ＰｂＯ２，ＳｎＯ２，ＴｉＯ２，ＳｉＯ２或Ｉｎ２Ｏ３等能明显地提高Ｚｎ粉在５ｍｏｌ／ＬＫＯＨ溶液中的缓蚀能力，此外，文中还应用分形理论对结果作了进一步的讨论．Zinc powders were electrodeposited from ZnCl 2 baths with containing suspension of unsoluble particles such as graphite, PbO 2,SnO 2,TiO 2, SiO 2 etc.. The structure, morphology and corrosion behavior of zinc powder were analyzed. SEM results showed that the dendritic growth of zinc can be inhibited by applying the suspension method. Suspension of PbO 2, SnO 2, TiO 2, SiO 2 and In 2O 3 could greatly improve the corrosion protection of zinc powder in 5 mol/L KOH. In addition, fractal theory is employed to further explain the results.作者联系地址：新疆大学化学系Author's Address: Dept. of Chem., Xinjiang Univ., Urumqi 83004

渡洪区浅覆盖层水域钢栈桥设计及施工

福州市闽侯二桥是一座主跨为 280m 的水滴型双塔斜拉桥，闽江主河道常年有流水，必须设置栈桥施工便道。桥位所在区域为渡洪区浅覆盖层水域，对于栈桥的设计及施工都提出了非常高的要求。根据现场实际情况，施工栈桥采用“板凳桩 + 锚固桩”的结构形式，通过计算分析表明：该栈桥结构的应力及位移均满足要求，可用于指导施工，且该栈桥已在福州市闽侯二桥项目成功应用，可为后续类似项目提供参考。</jats:p

Studies on the Preparation of Nanophase Electrode Materials and Its Electrochemical Properties(Ⅲ)—Performance of nm γ MnO 2 Obtained by Microemulsion Method

本文采用锰盐微乳液中通氧气法成功制备了超细粉末ＭｎＯ２，对所得样品进行了化学分析，ＸＲＤ，ＴＥＭ测试，证明为γＭｎＯ２，平均粒径在纳米级范围内．再经恒电流放电，循环伏安，分形维数，交流阻抗等测试，发现在适当制备条件下所得纳米ＭｎＯ２具有良好的放电性能，并对此作了初步的理论探讨A nanophase MnO 2 was synthesized using w/o microemulsion as reation media, The most favorable experiment conditions for the preparation of nm MnO 2 were researched. XRD,TEM,AC impedance, cyclic voltammetry etc. examinations were used to characterize the sample comparison with the classical MnO 2 (I.C.No.1EMD,electrolytic manganese dioxide). Sample shows that the crystal styucture of the synthesized samples are mainly γ MnO 2, with average particle size in the nanometer as shown by TEM. It was found that the discharge capacity of nm MnO 2 obtained is significantly higher than that of the I.C.No.1 EMD.作者联系地址：新疆大学应用化学所Author's Address: Department of Chemistry, Xinjiang University, Urumqi 83004

Preparation of Spinel LiMn_2O_4 at Low Temperature

Nanosized spinel LiMn 2O 4 was prepared by a sol-gel method. The preparation process was monitored by XRD, BET, DTA, TGA and TEM observations. It is found that at temperature higher than 350 ℃ the spinel phase of the samples could be detected by XRD, which is lower than that temperature in common solid-state preparation. The diameters of the samples calculated by Sherrer equation were increased with the temperature of calcination.国家自然科学基金!(2 98330 90 );; “八六三”高技术发展计划!(715 - 0 0 4- 0 2 5 0 )资助课