Some Effects of Co on the Electrochromic Properties of NiO xH y Film

本文利用阴极化电沉积法在抛光镍板及ＩＴＯ玻璃表面制备了含Ｃｏ量为１６．２％的ＮｉＯｘＨｙ薄膜，薄膜厚度分别为４２ｎｍ、２１ｎｍ，采用透射光谱以及线性电位扫描、交流阻抗和阳极稳态极化曲线等测试技术，考察了Ｃｏ对ＮｉＯｘＨｙ薄膜电致变色性能的影响，光谱测试范围为３００～２５００ｎｍ．结果发现：Ｃｏ能降低薄膜着色态在可见光区及部分近红外区的透过率，通过电压调节不仅可以调光而且可望能够控温；同时Ｃｏ还能降低ＮｉＯｘＨｙ薄膜电致变色电位，升高薄膜氧化着色过程中的氧析出过电位，对薄膜的电致变色性能有改进作用，但降低了着色过程中质子的扩散系数．Some effects of Co addition upon the electrochromic characteristics of a nic_kel hydroxide film were studied. The films were electrodeposited on both polished Ni plate and conductive ITO glass. The electrochemical behaviors were investigated using the film on Ni plate by linear potential sweep, a.c. impedance, and anodic polarization curves for OER(oxygen evolution reaction). It was found that Co can lower the working voltage and raise the oxygen overpotential, but has little effect on the reaction kinetics. It was also found that the Co can improve the optical properties of the electrochromic film.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

The Effect of Co on the Proton Diffusion Coefficient for the Ni(OH)2 Electrodes

本文采用恒电位阶跃、循环伏安及恒电流放电法，考察含Ｃｏ量０％～５３％的Ｎｉ（ｏＨ）_２电极充放电过程中质子的扩散系数：充电过程该值为１０－９～１０－１０ｃｍ２／ｓ，放电过程则为１０（－１１）ｃｍ２／ｓ．数据处理时对文献中有关公式进行了修正．The diffusion coefficients of protons moving in the Ni(OH)2 electrodes have being investigated by constant current,cyclic voltammetry and potential step technineques.The electrodes were prepared by cathodic deposition and their active material contained 0～53% cobalt.It was found that the diffusion coefficients are about 10(-9)～10(-10) cm2/s during charging and about 10(-11) cm2/s during discharging.Moreover the value increases with the increacing content of Co in the electrodes.During the calculation,the relevant fomulars were modified especially the wrong fomular for constant current methode.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 Energy Material Chemistry,Nankai University,Tianjin 30007

Oxygen Evolution Behavour on Ni Electrode in KOH Solution

用恒电流法测试在２２～７０℃之间电解３０ｗｔ．％ＫＯＨ水溶液时Ｎｉ阳极的稳态极化曲线以及该过程的交换电流密度ｉ０，Ｔａｆｅｌ斜率ｂ，传递系数β和不同电流密度下的析氧过电位随电解温度的变化关系结果发现：４０℃是各参量随温度变化的一个突出变点，４０℃以下，高过电位区的Ｔａｆｅｌ斜率达１２０ｍＶ以上，低过电位区的反应活化能Ｅａ为７９．８８ｋＪ／ｍｏｌ，而４０℃以上时，上述两参数分别为６０～７０ｍＶ和５５．３２ｋＪ／ｍｏｌ．另外两温度区间的（η／Ｔ）１及其随ｌｇｉ的变化也有显著差别The steady_state polarization curves of oxygen evolution were measured at temperatures between 22～70 ℃ on Ni electrode in 30 wt.% KOH solution by galvanostat methode. The exchange current densities, Tafel slopes and transfer coefficients were studied. It was found that 40 ℃ is a special temperature, near which the kinetic parameters change abrupdy. The Tafel slopes for oxygen evolution reactions at higher overpotentials change from more than 120 mV to about 70 mV when the temperature raises to 40～70 ℃ from 22～35 ℃. Simultaneously, the heat of activation is changes from 79.88 kJ/mol to 55.32 kJ/mol. Moreover, the -(η/Τ) i and how it changes with lg i are quite different in the two temperature ranges: The slope of -(η/Τ) i vs. lg i is 4.63 at the lower temperatures, while at the higher temperatures it is only -0.455.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

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

Studies of Electrochemical Characteristics of Pasted Nickel Hydroxide Electrode with Surface Deposited Cobalt

研究了在碱性可充电电池正极活性物质—球型氢氧化镍粒子表面化学镀钴后氢氧化镍电极的性能．通过比较充放电曲线和循环伏安试验结果，讨论了电极的放电容量、活性物质利用率和Ｎｉ（ＯＨ）２／ＮｉＯＯＨ氧化还原可逆性．实验还发现镀钴后的氢氧化镍电极有更好的充放电性能和优良的电极特性．测定了化学镀钴前后氢氧化镍电极的交流阻抗，表明镀钴后氢氧化镍的基体之间的有较低接触电阻．此外，本文还对钴镀层改进氢氧化镍性能的机理进行了讨论．The surface of the spherical nickel hydroxide particles used as an active material in pasted nickel electrodes is surface_deposited with cobalt. This paper investigated the effects of the amount of cobalt deposit on the characteristics of nickel hydroxide electrode. The performances of the electrode, such as discharge capacity, utilization of active material and reversibility of Ni(OH) 2/NiOOH redox reaction, were studied by comparing the charging/discharging curves and cyclic voltammograms. The mechanism of action of cobalt deposits has been described in terms of the electrochemical impedance spectroscopy of nickel hydroxide electrode.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 Enery Material Chemistry, Nankai University, Tianjin 30007

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

Influences of PTFE on Electrochemical Properties of FoamType Ni(OH)_2 Electrodes

用恒电流放电、循环伏安法和电化学阻抗谱（ＥＩＳ）研究了ＰＴＦＥ对泡沫型氢氧化镍电极电化学性能的影响，发现ＰＴＦＥ的存在会增加电极的电化学反应电阻，降低电极反应的可逆性，从而使得电极的放电电位及容量有所降低，所以在制作粘结式电极的过程中应尽量减少粘结剂的用量．Research work was performed for the influences of PTFE on the electrochemical properties of foamtype Ni(OH)_2 electrodes by constant current discharge. CV and EIS method. Experimental results exhibit that the existence of PTFE would decrease the reversibility of electrode reaction and increase the reaction resistance of the electrode; thus lower the discharge potential and capacity, so PTFE should be added as little as possible during the preparation of pastetype electrodes.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 Energy Material Chemistry, Nankai University, Tianjin 30007