Corrosion Behavior of Mg_(1.85)Mm_(0.15)Ni Hydrogen Storage Alloy Modified by Electroless Cu in CH_3OH·H_2O Solutions

　采用稳态极化曲线法和交流阻抗法研究了在甲醇 水不同含量镀液中化学镀铜的Mg1.85Mm0.15Ni(Mm∶富铈混合稀土)储氢合金于强碱性溶液中的抗腐蚀性能.结果表明,对甲醇＿水体系化学镀铜,合金的抗腐蚀性可进一步改善.其中以甲醇体积比含量为40%的镀液施镀的抗腐蚀效果最佳.稳态极化曲线测试给出,此时合金的腐蚀电流密度只有5.6mA·cm-2,相应的电化学反应阻抗为22.25Ω·cm2,而原粉的两者之值分别为11.7mA·cm-2和1.99Ω·cm2.The corrosion behavior of the Mg1.85Mm0.15Ni (Mm:Ce_rich mischmetal) alloy modified by electroless Cu coating in different CH3OH_H2O solutions has been investigated by potentiodynamic polarization and electrochemical impedance spectroscopy. These results showed that the corrosion behavior was improved after electroless Cu. The potentiodynamic polarization and electrochemical impedance spectroscopy results showed that the alloy electrode had more promising anti_corrosion behavior after coated in a 40%CH3OH_H2O solution. The values of corrosion current density and electrode reaction resistance were 5.6 mA·cm-2(11.7 mA·cm-2 for uncoated alloy electrode) and 22.25 Ω·cm2 (1.99 Ω·cm2 for the uncoated alloy electrode), respectively.作者联系地址：南开大学能源材料化学研究所,南开大学能源材料化学研究所,南开大学能源材料化学研究所,南开大学能源材料化学研究所,南开大学能源材料化学研究所 天津300071 ,天津300071 ,天津300071 ,天津300071 ,天津300071Author's Address: College of Chemistry Institute of New Energy Material Chemistry, Nankai University, Tianjin 300071,Chin

Corrosion Behavior of Mg_(2-x)La_xNi and Mg_(2-x)Ce_xNi Hydrogen Storage Alloy

应用电化学方法研究了Mg2-xLaxNi及Mg2-xCexNi储氢合金的腐蚀性能.恒电位极化和交流阻抗测试表明,经Ce或La取代后的合金,其前者腐蚀电流及电化学极化电阻均随Ce取代量增加而降低,而后者的腐蚀电流却随La取代量的增加而增加,但极化电阻则呈先降后升趋势.合金极化后SEM测试显示,经Ce取代后合金表面较平整,而用La取代的则明显有裂纹.作者认为这主要与La、Ce的氧化物的结构有关.The corrosion behavior of Mg-base hydrogen storage alloys has been investigated by potentiodynamic polarization and EIS. The results showed that the corrosion current density (i_(corr) ) and the electrochemical polarized resistance of Mg_(2-x)Ce_xNi alloys decreased with x increase, while i_(corr) of Mg_(2-x)La_xNi alloys increased and the electrochemical polarized resistance of Mg_(2-x)La_xNi alloys increased first, then decreased with x increase. SEM results showed that the surface of Mg_(1.85)Ce_(0.15)Ni alloy was relatively even while the surface of Mg_(2-x)La_xNi alloy had remarkedly cracks. The different behavior between Ce and La may be relevant to the structure of Ce, La oxides.作者联系地址：南开大学新能源材料化学研究所,南开大学新能源材料化学研究所,南开大学新能源材料化学研究所,南开大学新能源材料化学研究所 天津300071 ,天津300071 ,天津300071 ,天津300071Author's Address: College of Chemistry Institute of New Energy Material Chemistry,Nankai University,Tianjin 300071,Chin

Electrochemical Stability of PVA Alkaline Gel Polymer Electrolyte Membranes

应用溶解—铸膜法制备聚乙烯醇(polyvinylalcohol,PVA)碱性凝胶聚合物电解质(gelpolymerelectrolyte,GPE)薄膜.交流阻抗(EIS)测试表明,随着KOH含量的增加,该薄膜的离子电导率表现为先增大而后减小的变化趋势,当KOH含量为42%(bymass,下同)时,电导率达到最大值,为2.01×10-3S/cm.X射线衍射(XRD)结果表明,当膜中KOH含量大于20%时,晶态的PVA就逐渐转变为非晶态结构.又当KOH含量增加到一定值后,由于体系中未电离的非晶态KOH量的增多而导致离子电导率下降.循环伏安(CV)和拉曼光谱(Raman)结果表明,该薄膜具有很好的电化学稳定性,可应用于碱性二次电池.Polyvinyl alcohol (PVA) alkaline polymer gel electrolyte(GPE) membranes were successfully prepared by a solution-casting technique and their electrochemical stabilities were investigated. The electrochemical impedance spectrum (EIS) results showed that the ionic conductivity of the PVA alkaline GPE membranes first increased with the increase of KOH content, then decreased with the further increase of KOH. When the weight percentage of the KOH in the PVA alkaline GPE membrane approached to 42%, it exhibitedthe highest ionic conductivity of 2.01×10~(-3 ) S/cm at room temperature (R.T.). The X-ray diffraction (XRD) results revealed that with the increase of KOH the crystalline of the PVA was disrupted and converted into an amorphous phase. While the ionic conductivity decreased due to the increase of the amorphous unionized KOH in the membranes with the further increase of KOH. The cyclic voltammograms (CV) and Raman spectra indicated that the GPE membranes had promising electrochemical stabilities. It is suggested that the PVA alkalineGPE membranes could be used for practical applications in alkaline rechargeablebatteries.作者联系地址：南开大学新能源材料化学研究所,南开大学新能源材料化学研究所,南开大学新能源材料化学研究所,南开大学新能源材料化学研究所 天津300071 ,天津300071 ,天津300071 ,天津300071Author's Address: Institute of New Energy Material Chemistry, Nankai University, Tianjin 300071,Chin

Influence of Rare Earth Oxide on the Performance of Secondary Zinc Electrodes

应用阴极极化法在锌电极上覆盖一层稀土氢氧化物膜La(OH)3或Ce(OH)3,并用循环伏安、动电位极化、定电位阴极极化实验研究其电化学性能.结果表明,La(OH)3或Ce(OH)3膜能抑制锌酸根离子的迁移,提高析氢过电位,降低腐蚀电流密度并能抑制枝晶生长.SEM观测显示,稀土氧化物La2O3或CeO2改变了锌沉积形态,进而提高了锌酸钙电极的充放电循环性能.Influence of La(OH)_(3 )or Ce(OH)_3in secondary zinc electrode was investigated by the cyclic voltammetry, potentiodynamic polarizationand potentiostatic polarization tests and influence of La_2O_3or CeO_2in the charge/discharge performance of Zn/Ni battery was studied by galvanostatic charge/discharge experiment. The results showed that the film of rare earth hydroxide prevented the zincate species from transferring toward solution, enhanced hydrogen overpotential and decreased thecorrosion current density (i_(corr)), and therefore inhibited zinc corrosion. The potentiostatic polarization results at100mV overpotential showed thatLa(OH)_3or Ce(OH)_3coated on the zinc electrode effectively suppressed the zinc dendrite growth. The La_2O_(3 )or CeO_2addition to the calcium zincate electrode improved the cycle performance of Zn/Ni battery.作者联系地址：南开大学新能源材料化学研究所,南开大学新能源材料化学研究所,南开大学新能源材料化学研究所,南开大学新能源材料化学研究所 天津300071 ,天津300071 ,天津300071 ,天津300071Author's Address: Institute of New Energy Material Chemistry, Nankai University, Tianjin 300071,Chin

Behavior of Copper in Hydrogen Storage Alloy Microencapsulated by Copper

在密封的电池体系中（即贫液状态），包铜储氢合金电极具有较好的抗氧化能力；而在强碱性溶液中（即富液状态），铜在电极工作的电位范围内（－１．１～－０．４Ｖ）具有一定的稳定性，但当扩展扫描范围（－１．１～－０．２Ｖ），将出现铜的氧化还原反应．随着充放电循环的进行，铜被氧化成Ｃｕ２Ｏ，进而形成ＣｕＯ２－２进入电解质（ＫＯＨ）溶液中，充电时又以Ｃｕ的形式于电极表面析出．针对这一现象，本文利用电位阶跃实验研究了ＣｕＯ２－２离子在镍电极上的电沉积过程，结果表明该过程遵循二维瞬时成核机理Negative electrode made from Cu microencapsulated hydrogen storage alloy was studied by using cyclic voltammetry method. The results showed that copper as a coating material was of a certain stability in 5 mol/L KOH solution within the range of charge and discharge voltage. But when expanding the sweep voltage, the CV curve showed a pair of distinct oxidation reduction current peaks of Cu 2O formation at E =-0.3 V and Cu 2O reduction at E =-0.6 V. With charging discharging cycles, copper is liable to be oxidized to Cu 2O and further oxidized into CuO 2- 2. When charged again, CuO 2- 2 anion is reduced and Cu is electrodeposited on the sufrace of electroce. In respond to this phenomenon, the electrodeposition process of CuO 2- 2 on the smooth Ni electrode was studied by constant potential step technique. The results showed that the deposition process of copper followed the two dimension instantaneous mechanism.作者联系地址：南开大学新能源材料化学研究所Author's Address: Inst. of New Energy Material Chem., Nankai Univ., Tianjin 30007

Preparation and Electrochemical Preformance of Zn-La Alloys

　采用固相扩散法合成Zn＿La合金,并研究La对锌电极化学性能的影响.实验表明:La的适量添加能抑制锌电极的枝晶及腐蚀等问题,从而明显改善锌电极的循环性能,其中以0.5at.%La的添加量为最佳.在100mA/g电流密度下,循环80周期后,其放电容量仍达520mAh/g,XPS测试表明,La主要以La2O3/La(OH)3的形式附着在锌电极表面上.正是由于La2O3/La(OH)3的存在,显著改善了锌电极的循环充放电寿命.Zn_La alloys were prepared by solid phase diffusion method and the effects of La on the electrochemical performance of zinc electrodes were investigated using potentiostatic polarization technique and charging/discharging cycle test. The results showed that adding La to zinc electrode remarkably suppressed the zinc dendrite, the shape of zinc electrode and zinc corrosion, and hence, markedly improved the cycle performance of zinc electrodes. The discharging capacity of the zinc electrode containing 0.5at.% La which was the optimum was still 520 mAh/g after it cycled 80s at the current of 100 mA. The XPS showed that La element mainly adhered on the surface of the zinc electrode in the form of La2O3/La(OH)3 that evidently enhanced the cycle life of the secondary zinc electrode.作者联系地址：南开大学新能源材料化学研究所,南开大学新能源材料化学研究所,南开大学新能源材料化学研究所,南开大学新能源材料化学研究所,南开大学新能源材料化学研究所,南开大学新能源材料化学研究所,南开大学新能源材料化学研究所 天津300071 ,天津300071 ,天津300071 ,天津300071 ,天津300071 ,天津300071 ,天津300071Author's Address: Institute of the New Energy Material Chemistry,Nankai University,Tianjin 300071,Chin

Development on Hydriding/Dehydriding Kinetics of Mg Nano-materials for Hydrogen Storage

综述近十年来国内外有关纳米镁储氢材料吸放氢动力学的研究现状和发展趋势.众多研究表明,应用高能球磨法制备纳米镁复合储氢材料,并以过渡金属氧化物为催化剂,或者用ABx型储氢合金与镁复合,都能显著改善镁的吸放氢动力学性能.The development of Mg nano-materials for hydrogen storage in the recent decade has been reviewed in this paper.It was shown the Mg nano-powders prepared by high-energy ball milling showed promising hydriding and dehydriding performance with the transition metal oxides and other types of hydrogen storage alloys(ABx)as the catalysts.作者联系地址：南开大学新能源材料化学研究所,南开大学新能源材料化学研究所,南开大学新能源材料化学研究所,南开大学新能源材料化学研究所,南开大学新能源材料化学研究所 天津300071,天津300071,天津300071,天津300071,天津300071Author's Address: Institute of New Energy Material Chemistry,Nankai University,Tianjin 300071,Chin

Hydriding and Dehydriding Properties of Mg/Mg_(1.8)La_(0.2)Ni Nanocomposites

应用高能球磨法制备Mg-x%Mg1.8La0.2Ni(x=10、20和30)纳米复合储氢材料.X射线衍射(XRD)、透射电镜(TEM)和选区电子衍射(SAED)测试表明,该复合材料具有纳米晶和非晶态混合结构的性质,吸氢温度降低,较好的吸放氢动力学性能,在423K,2.5MPa氢压的条件下,50s内即可达到最大吸氢量.Mg-x %Mg1.8La0.2Ni(x=10,20 and 30)nanocomposites have been synthesized by high-energy ball milling method.Results of the X-ray diffraction(XRD),transmission electron microscopy(TEM)and selected area electron diffraction(SAED)tests were showed that each composite had a nanocrystalline/amorphous structure,which was beneficial for the improvement of the hydriding and dehydriding properties of Mg.The hydrogen absorption temperature decreased and the hydrogen sorption kinetics were improved.Under the conditions of 423 K and the hydrogen pressure of 2.5MPa,each composite could reach the maximum hydriding capacity within 50 s.作者联系地址：南开大学新能源材料化学研究所,南开大学新能源材料化学研究所,南开大学新能源材料化学研究所,南开大学新能源材料化学研究所,南开大学新能源材料化学研究所 天津300071,天津300071,天津300071,天津300071,天津300071Author's Address: Institute of New Energy Material Chemistry,Nankai University,Tianjin 300071,Chin

Electrochemical Properties of Sub-micron Li_4Ti_5O_(12) Powders

应用改进固相合成法制备亚微米Li4Ti5O12锂离子电池材料.X射线衍射(XRD)、扫描电镜(SEM)和激光粒度分析分别显示:物相单一且粒度均匀,D50为0.886μm,属于亚微米级材料.合适的粒度和分布使得该材料展示出优良的电化学性能,以其装配的半电池中,0.1C首次放电容量为165 mAh/g,5C时放电容量可达107 mAh/g,10C时仍可达到54 mAh/g.The sub-micronmeteric Li4Ti5O12 powder material was successfully prepared through an improved solid-state synthesis process.The results of X-ray diffraction(XRD),scanning electron microscopy(SEM) and laser particle size distribution analysis showed that only a single spinel phase and a normal distribution pattern with the average size(D50) of 0.886μm could be observed.Due to the suitable partical size distribution,the Li4Ti5O12 powders showed a promising electrochemical performance.At the discharge current densities of 0.1C(16.5 mAh/g) and 5C,the discharge capacities reached 165 mAh/g and 107 mAh/g,respectively.Even at 10C,it still reached 54 mAh/g.作者联系地址：南开大学新能源材料化学研究所;天津巴莫科技股份有限公司;Author's Address: 1.Institute of New Energy Material Chemistry,Nankai University,Tianjin 300071,China;2.Tianjin B&M Science Technology Joint-Stock Co LTD,Tianjin 300384,Chin

Properties of Zr-based Laves Phase Hydrogen Storage Electrode

Ｚｒ（Ｖ＿（０．２）Ｍｎ＿（０．２）Ｍｏ＿（０．０６）Ｎｉ＿（０．５４））＿（２．４）合金经ＨＦ溶液处理后，合金表面由富Ｚｒ和富Ｍｎ层转变成富Ｎｉ层，从而使电极初期活化周期明显缩短，电极表面氢吸附性能改善，表面反应电阻减小。本文探讨了上述电极表面反应机理，即表面Ｎｉ的催化、氢吸附和氢转移机理。对阻抗谱进行拟合，给出了相应的电极反应等效电路。After treated by HF solution,the surface of Zr(V_(0.2)Mn_(0.2)Ni_(0.54)Mo_(0.06))_(2.4) alloywas transformed from Zr-rich and Mn-rich layer to Ni-rich layer.In this way,the nickel on thesurface could be believed to be the Raney-type nickel, which could obviously shorten the activationcycles,improve electrocatalytic activity and hydrogen adsorption ability.In this paper,the reactionmechanism on the alloy surface(i.e. the mechanism of nickel-catalysis,hydrogen-adsorption andhydrogen-transference)had been investigated.And the impedance spectra were fitted to an equivalentcircuit using a non-linear,least-squares(NLLS)fitting program.作者联系地址：南开大学新能源材料化学研究所Author's Address: Institute of New Enorgy Material Chemistry,Nankai University,Tianjin 30007