阀控密封铅酸蓄电池反应机理分析

作为电动车用电池，铅酸蓄电池仍然存在着比能量低、充电接受能力差、活性物质利用率低等缺点，板栅的腐蚀、负极硫酸盐化、析氢、析氧等现象会引起充放电过程中不必要的副反应，这将导致电池容量的损失及衰减。总结了阀控密封铅酸蓄电池（VRLA）及其正负极的反应机理，并对各种反应机理做了比较和评价。详细介绍了负极反应中溶解沉淀机理、固相反应机理和固相反应-溶解沉淀机理，以及正极反应中胶体结构上的PbO2形成机理、液相生成机理和固相生成机理。最后提出了提高铅酸蓄电池性能的几种方法，并对铅酸蓄电池的发展做出了展望。     

Synthesis of nano-sized Co<Subscript>3</Subscript>O<Subscript>4</Subscript> powder by spray conversion method for anode material of lithium battery

A nano-sized Co₃O₄ powder was prepared using a spray conversion method that could be applied for mass production. The spray-conversion process consisted of spray drying of a metallic liquid solution, a calcination treatment, and a ball milling process. The calcined Co₃O₄ powder consisted of agglomerated spherical clusters with nano-sized particles. After milling for 24 h, agglomerated powders were fragmented into fine powders sized below 60 nm. The lithium/cobalt oxide cell was charge-discharged at a constant current density of 0.2 mAcm⁻² and showed a first discharge capacity of 1100 mAhg⁻¹. The discharge capacity of the Li/Co₃O₄ cell drastically decreased with cycle number. By increasing the carbon content of the anode, the cycle life was improved. For a Co₃O₄ electrode containing 40 wt.% carbon, the discharge capacity was over 400 mAhg⁻¹ after 50 cycles. The spray conversion method might be a useful method to prepare nano-sized Co₃O₄ powder for the anode material of lithium batteries.     

Effects of synthesized 4PbO·PbSO4 on the Initial capacity and cycle performance of lead dioxide electrode prepared by cementation leady oxide

The service life of lead-acid batteries is often limited by disintegration of the positive active mass structure. It is known that the latter depends on the phase composition, crystal morphology and paste density. In general, the electrode whose active mass is prepared from 4PbO·PbSO₄ pastes (denoted by 4BS_pas) has about 30% longer cycle lives than those obtained by 3PbO·PbSO₄·H₂O. Therefore, the initial capacity and cycle performance of lead dioxide electrodes prepared from 10, 30 and 50 wt.% 4BS_syn (chemically synthesized 4PbO·PbSO₄) addition with regard to the amount of cementation leady oxide were examined. Lead oxide (denoted by cementation leady oxide) was prepared by the pulverization of sponge lead prepared from a cementation reaction under the conditions of 90°C and 1.0 wt%HCl solution. 4BS_syn crystals were chemically synthesized in 40.1 wt.%H₂SO₄ with \-PbO. Without 4BS_syn, crystals lead dioxide electrode has shown a higher initial capacity than any other 4BS_syn contents and cycle performance was the best although the initial capacity is relatively low for 50 wt.% 4BS_syn.     

基于银氧化物电极的高比能电池研究进展

基于银氧化物电极(银电极)的高比能电池具有比能量大、输出功率高、放电平稳、安全可靠等优点;银电极作为此类电池的关键部件,决定着电池性能的优劣。简要介绍了银电极的工作原理和制备方法;详细分析了银电极中AgO分解、两坪阶电位、活性物质利用率和高倍率放电性能等研究现状;综述了锌银、铝银和锂银等几类基于银电极的高比能电池的原理与特点、发展与应用、性能与改进方法等;对基于银电极的高比能电池的发展方向进行展望。     

The performances of proto-type Ni/MH secondary batteries using Zr-based hydrogen storage alloys and filamentary type Ni

For the purpose of developing a Zr-based Laves phase alloy with higher capacity and better performance for electrochemical application, extensive work has been carried out. After careful alloy design of ZrMn₂-based hydrogen storage alloys through varying their stoichiometry by means of substituting or adding alloying elements, the Zr_0.9Ti_0.1(Mn_0.7V_0.5Ni_1.4)_0.92 with high capacity (392 mAh/g at the 0.25C) and improved performance (comparable to that of commercialized AB₅ type alloy) was developed. Another endeavor was made to improve the poor activation property and the low rate capability of the developed Zr-based Laves phase alloy for commercialization. The combination method of hot-immersion and slow-charging was introduced. It was found that electrode activation was greatly improved after hot immersion at 80°C for 12h followed by charging at 0.05C. The effects of this method are discussed in comparison with other activation methods. The combination method was successfully applied to the formation process of 80 Ah Ni/MH cells. A series of systematic investigations has been rendered to analyze the inner cell pressure characteristics of a sealed type Ni-MH battery. It was found that the increase of inner cell pressure in the sealed type Ni/MH battery of the above-mentioned Zr−Ti−Mn−V−Ni alloy was mainly due to the accumulation of oxygen gas during charge/discharge cycling. The fact identified that the surface catalytic activity was affected more dominantly by the oxygen recombination reaction than the reaction surface area was also identified. In order to improve the surface catalytic activity of a Zr−Ti−Mn−V−Ni alloy, which is closely related to the inner pressure behavior in a sealed cell, the electrode was fabricated by mixing the alloy with Cu powder and a filamentary type of Ni and replacing 75% of the carbon black with them; thus, the inner cell pressure rarely increases with cycles due to the active gas recombination reaction. Measurements of the surface area of the electrode and the surface catalytic activity showed that the surface catalytic activity for the oxygen recombination reaction was greatly improved by the addition of Cu powder and the filamentary type of Ni. Finally, we have collaborated with Hyundai Motors Company on fabrication of the 80Ah cells for Electric Vehicles and evaluated the cell performance. This article based on a presentation made in the symposium “The 2nd KIM-JIM Joint Symposium: Hydrogen Absorbing Materials”, held at Hanyang University, Seoul, Korea, October 27–28, 2000 under the auspices of The Korean Institute of Metals and Materials and The Japan Institute of Metals.     

卷绕铅酸电池泡沫铅负极电化学行为的研究

以泡沫铅作为负极集流体制备了卷绕VRLA电池.采用计时电流法、循环伏安曲线、电化学阻抗谱和充放电实验研究了泡沫铅负极的电化学行为,结果表明泡沫铅负极的真实表面积比铅箔负极的大,因此泡沫铅负极具有较低的过电势,并且不论是在怎样的放电状态下,泡沫铅负极的电化学反应电阻较小;与铅箔负极相比,在10、5和2小时率放电状态下,泡沫铅负极的质量比容量分别增加25.9%,30.0%和48.2%.此外,SEM观察显示,泡沫铅负极表面活性物质为更加细小的晶体颗粒和具有更高的孔率.     

The effects of the particle size and active materials on the discharge properties of the Li/Fe(X)S<Subscript>2</Subscript> electrode

Although Li/S batteries produce an efficient initial discharge capacity, they have poor cycle characteristics due to the loss of the active material that occurs in these batteries. Therefore, the material of the metal sulfide series has recently been studied as a substitute. In the present study, the possibility of fine FeS₂ and Fe(x)S₂ compound powders (x=Ni, Co, Mo) are examined using a mechanical alloying method, and the discharge capacity is measured. The mean particle size of the FeS₂ compound powders was measured to be 600 nm at a milling time of 40 h. This data was attained through the utilization of the SEM morphologies. The initial discharge capacity of a Li/FeS₂ battery was 430 mAh/g-FeS₂ if into a fine powder for 20 h milled, and 890 mA/g-FeS₂ if into a fine powder for 30 h milled. Moreover, it was found that if there is an addition of Ni or Co into the compound, it would increase the discharge properties. Fe(x)S₂ composite powders were synthesized in order to improve the cycle life of the battery. From the charge-discharge test results, the initial discharge capacity of the Fe(Ni)S₂ electrode was 845 mAh/g. The initial discharge capacity of the Fe(Co)S₂ electrode was 500 mAh/g, but it showed a better cycle performance than the discharge capacity of electrodes with either additions of Ni or Mo.     

Mesoporous Nanostructured Materials for the Positive Electrode of a Lithium–Oxygen Battery

Nanostructured carbon materials (CMs), the structure can vary widely, are promising materials for the positive electrode of a lithium–oxygen battery (LOB). The electrochemical characteristics of CMs studied in model conditions and their porous structure, as well as testing them as an active material for the positive electrode in an LOB sample, show that nanotubes (CNTs) and Super P carbon black possess the highest charge–discharge characteristics in an aprotic solvent (DMSO). Mono- and bimetallic systems containing Pt, Pd, and Ru and synthesized on CNT and Super P allow one to reduce discharge and charge overvoltage. In the presence of catalytic systems, an improvement in the energy-conversion efficiency of up to 73–76.7% is achieved for the LOB positive electrode. The possibility of achieving a stable cycling process in an LOB with a positive electrode on the basis of developed catalysts and with a LiClO₄/DMSO electrolyte is shown. For the first time, the positive influence of iodine (reducing the charge voltage to about 0.8–1.0 V as compared to the characteristics of an LOB using an electrolyte without additives) on the electrode characteristics of a Li–O₂ cell with the highly electron-donating solvent DMSO is demonstrated.     

Fabrication and characterization of a SnO2−RuO2 composite anode for a hybrid thin film battery

A SnO₂−RuO₂ composite (SnRuO) thin film possesses unique electrochemical properties for a hybrid between batteries and supercapacitors due to the fact that the SnRuO system shows battery and supercapacitor characteristics simultaneously. SnRuO thin films were prepared through the magnetron co-sputtering method in order to investigate the feasibility of a monolithic thin film hybrid battery. The SnRuO thin film as an anode film for a secondary battery demonstrated a first discharge capacity of 1557 μAh/cm²·μm; the second discharge capacity was 52% of the first discharge capacity. The degree of capacity fade of the SnRuO thin film was almost the same as that of the SnO₂ thin film, even though the capacity of the SnRuO thin film was larger than that of the pure SnO₂. In addition, the SnRuO thin film showed a supercapacitor behavior and exhibited a specific capacitance of 14 mF/cm² μm during 1000 cycles. These results suggest that SnRuO thin film could be used as a thin film supercapacitor as well as a thin film battery. Furthermore, this composite thin film holds promise for the fabrication of a monolithic thin film high power hybrid battery based on micro-processes.     

A pyrometallurgical alternative: The refining electrolysis of lead and solder

Conclusions  In refining electrolysis in hexafluorosilic acid with current densities of 100 A/m², it is possible to separate bismuth and antimony from prerefined lead bullion. Pure lead with less than 50 ppm bismuth and less than 100 ppm antimony was deposited at the cathode. The current efficiency was 99%, and the specific energy consumption was 30–40 kWh/t. Under the same conditions, a lead-tin alloy with less than 300 ppm antimony can be produced by refining a Pb−Sn−Sb alloy with 30% tin and up to 5% antimony. In this case, antimony remains in the anode sludge. Because of the high amount of anode sludge, the strong adhesion of the sludge on the anode surface, and its physical properties in the case of high antimony contents (i.e., more than 5% antimony in the anodes), some differences in the usual electrolysis technology are necessary to guarantee a long-term, stable, and trouble-free electrolysis. The tendency of anode passivation can be reduced by using a periodic current reversal technique. This technique results in a smaller amount of anode sludge, a reduced loss of lead in the anode sludge, and lower anodic polarization values.     

动力锂离子电池电极结构对其极化特性影响的仿真研究

基于COMSOL数值仿真平台构建锂离子动力电池电化学-热耦合模型,深入研究了正极材料厚度,正、负极材料颗粒半径与电池内部极化间的作用规律,并在此基础上,归纳阐明了动力锂离子电池放电电压平台衰退、放电周期骤减与电池内部极化间的内在关联。结果表明:正、负极活化极化随正极厚度的增加变化差异较大,正极活化极化在18~31 m V之间波动,而负极可达到260 m V;放电末期负极固相浓差极化急剧增加,最大值达到425 mV。正极颗粒半径对极化的影响较小;负极颗粒半径减小为原来的一半,即0.5Rn时放电中期的负极活化过电势约为55 mV,较1Rn降低45%左右。负极活化极化的增加将导致电池放电电压平台下降,负极活化极化和固相浓差极化在放电末期急剧增加,是电压提前达到放电截止电压的最主要原因。     

田口-灰关联法应用于Inconel 718微放电铣削参数最佳化(英文)

应用田口-灰关联法对Inconel 718微放电铣削多重质量特性如电极消耗率、材料去除率和扩口量进行最佳化,分析放电电流、脉冲时间、休止时间和极间间隙对加工Inconel 718之电极消耗率、材料去除率和扩口量的影响。实验结果表明,以最佳微放电铣削参数进行加工,其电极消耗率由5.6×10-9mm3/min降低到5.2×10-9mm3/min,材料去除率由0.47×10-8mm3/min增加到1.68×10-8mm3/min,扩口量由1.27μm降低到1.19μm。研究结果显示,应用田口-灰关联法,可以改善微放电铣削多重质量特性。     

High temperature charging efficiency and degradation behavior of high capacity Ni−MH batteries

Recently the Ni/MH secondary battery has been studied extensively to achieve higher energy density, longer cycle life and faster charging-discharging rate for electric vehicles and portable computers, and etc. In this work, the charging efficiency of the Ni−MH battery which uses Ni electrode with addition of various compounds and the degradation behavior of the 90Ah battery were studied. The battery using the Ni electrode with Ca(OH)₂ addition showed the charging efficiency and the utilization ratio significantly better than electrodes without added compounds. After 418 cycles, the residual capacities at the Ni electrode showed nearly the same values in the upper, middle and lower regions. In the case of the MH electrode, the residual capacity in the upper region appeared lower than that in other regions. As a result of ICP analysis, the amount of dissolved elements in the three regions appeared almost the same. The faster degradation in the upper region of the MH electrode was caused by the TiO₂ oxide film formed at the electrode surface because of overcharging. The thickness of the oxide film increases with cycling, so it will form a layer that is not able to allow hydrogen to penetrate into the MH electrode. This article based on a presentation made in the symposium “The 2nd KIM-JIM Joint Symposium: Hydrogen Absorbing Materials”, held at Hanyang University, Seoul, Korea, October 27–28 under the auspices of The Korean Institute of Metals and Materials and The Japan Institute of Metals.     

An application of electrochemical method for studying nano-composite plating

Nickel plating is investigated using an electrochemical method in this study. Cathodic polarization indicated that electrode polarization at a current density of 10⁻¹ A/cm² increased by approximately 100 mV in a pH range 3–5, and by nearly 150 mV with 1 g/L of carbon powder in a Watts solution, as compared to bare nickel. The influence of inert particles such as carbon powder, silicon carbide and rice husk ash included in the nickel deposit was studied further using a potentiodynamic technique. Results showed that a co-deposit of nano-particles increased cathodic polarization. With a three-fold increase of the carbon powder in the plating solution, the polarization potential of the nickel deposit was doubled at a current density of 10⁻² A/cm². Passivation of the nickel deposit in the presence of all of the inert particles studied was improved in the area of hundreds of times higher compared to a bare nickel deposit. By increasing the amount of inert particles to twenty times the original amount, the passive current density was decreased by 85–95%. A co-deposit of rice husk ash in the nickel deposit decreased the passive current density by 98%, compared to a carbon and silicon carbide powder. Thus, rice husk ash has the potential to improve the pitting corrosion resistance of nickel composite plating.     

Physico-chemical properties of PbO2-anodes modified by Bi3+ ions

Physico-chemical properties of PbO₂-anodes modified by bismuth have been investigated in this work. The incorporation of Bi³⁺ dopant in the deposition solution allows one to obtain modified lead dioxide materials, bismuth content in which growths as increases its concentration in the solution. It was established that current density 10 mAcm^?2 and (10 ± 1)°C are optimal conditions for the deposition of lead dioxide modified by bismuth. In this case deposits appear shiny dark grey, with 1 mm thickness and good adhesion to the substrate. Resulting materials have had compact structure with spindle-shaped submicron and nanosized crystals. The increasing of the bismuth content in the deposit leads to the oxygen overpotential growth and enhancing of the oxidation rate of p-nitroaniline due to increase of the bond strength of chemisorbed oxygencontaining particles with the electrode surface.     

Effect of current density and perchloric acid concentration on the formation of lead anodes in sulphuric acid baths

At. appr. 1.66 volts and relatively low current densities PbO₂₊ ions are able to diffuse through the pores of the lead dioxide layer being formed and may be oxidised directly to yield PbO₂. In the presence of perchloric acid in the sulfate is formed in the pores of the lead dioxide layer at perchloric acid concentration exceeding 0.1 N. When formation adjuvants — which, on principle, are desirable — are used, certain concentrations must not be exceeded therefore. In addition, it is necessary to maintain the current density around 0.45 ma/cm² because only under such conditions the porosity of the lead dioxide layer is sufficient for the diffusion of Pb²⁺ ions. The possibility of a direct oxidation of Pb²⁺ ions. is shown in terms of the calculated current consumption in the different formation stages.     

The electroremoval of copper from dilute waste solutions using Swiss-roll electrode cell

Copper is usually present in concentrations less than 5 g/L⁻¹ in dilute waste solutions. The low concentrations make these solutions unsuitable for the electro-flow owinning processes via conventional electrolysis cells. Unconventional, two-and three-dimensional electrode cells with relatively large cathodic area are essential for such treatment. Different types of cells are mentioned in the literature. Among these cells, the two-dimensional Swiss-roll cell (SR) is considered in this study. The effects of cathodic current densities, initial copper concentrations, free sulfuric acid concentration, the presence of iron and zinc cations, and the rate of flow of the solution on both the cathodic current efficiency and power consumption were studied. Copper was removed from synthetic and industrial mixtures of Cu/Fe/Zn sulfate solutions to less than 5 ppm with power consumptions of 10.326 kWh/kg⁻¹ and 8.61 kWh/kg⁻¹, respectively. The correlation between the SR cell and packed-column cell on such treatment was also considered.     

Degradation analysis of nickel／metal hydride battery and its electrodes materials

The results indicate that during charge and discharge, the expansion of Ni(OH)2 crystal, pulverization of MH alloy particles and falling off from current collector are identified as the main causes for deterioration of Ni/MH batteries. Meanwhile, the contact resistance of inner battery increases due to the deterioration of the negative and positive electrode, and these changes lead to increasing battery body temperature and damaging its electrode and separator. The fibre‘s expansion and hole‘s diminishment of battery’s separator after degradation will affect the electrochemical performance and cycle life of Ni/MH batteries.     

Electrochemical properties of LiNi0.8Co0.2?xAlxO2 (0≤x≤0.1) cathode particles prepared by spray pyrolysis from the spray solutions with and without organic additives

Fine-sized LiNi_0.8Co_0.2−xAl_xO₂ (0≤x≤0.1) cathode particles were prepared by spray pyrolysis from the spray solutions with and without organic additives. Citric acid, ethylene glycol, and Drying Control Chemical Additive (DCCA) were used as organic additives and improved the morphologies and electrochemical properties of the cathode particles. The LiNi_0.8Co_0.2−xAl_xO₂ (0≤x≤0.1) cathode particles obtained from the spray solutions with organic additives were of micro size and had slightly aggregated morphologies. The initial discharge capacities of the LiNi_0.8Co_0.2−xAl_xO₂ (0≤x≤0.1) cathode particles obtained from the spray solutions without organic additive changed from 169 mAhg⁻¹ to 190 mAhg⁻¹ when the x changed from 0 to 0.1. However, the initial discharge capacities of the cathode particles obtained from the spray solutions with organic additives changed from 196 mAhg⁻¹ to 218 mAhg⁻¹. The initial discharge capacity of the LiNi_0.8Co_0.15Al_0.05O₂ cathode particles obtained from the spray solution with organic additives was maintained after the 20th cycle at a current density of 0.1 C.     

Use of optical absorption spectroscopy for the characterization of an Ar−Ti magnetron discharge

The density of ground state and metastable Ti atoms were measured in a magnetron sputtering reactor with a 10 cm diameter Ti target by using resonant optical absorption spectroscopy. Experiments were conducted under various discharge parameters, namely the discharge current (0.2 A to 1.2 A) and the distance from the target (2 cm to 12 cm) under two working pressures (0.5 Pa and 4 Pa). The results were compared with previous results for a smaller magnetron source with a 5 cm diameter target. The Ti densities were as follows: [Ti]≈10¹¹ cm⁻³, [Ti_m]=10¹⁰ to 10¹¹ cm⁻³ for 0.5 Pa and [Ti]≈[Ti_∞]=10¹⁰ to 10¹² cm⁻³ for 4 Pa. The portion of Ti metastables in the discharge increases by a factor of approximately 2 as the working pressure increases.