High-temperature electrochemical performance and phase composition of Ti_(0.7) Zr_(0.5) V_(0.2) Mn_(1.8-x)Ni_x hydrogen storage electrode alloys

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A new regeneration process for spent nickel/metal hydride batteries

Ultrasonic method was used to recycle nickel/metal hydride（MH-Ni） batteries under undestroyed state. The effects of ultrasonic on electrode material performance of MH-Ni batteries were investigated by using SEM, EDAX and XRD. The results indicate that with the ultrasonic time increasing, there are obvious dispersing phenomena in the positive and negative electrodes. This can make the inertia oxidation layer break off from the negative electrode, and the fresh surface comes out. These changes can increase the reaction centers of the active materials, as welt as improve the catalysis capability and discharge ability. But if the ultrasonic time is too long, it can make the active materials reunite and accelerate its pulverization, and lead to its degradation. The improvement of electrochemical performance for MH-Ni batteries is obvious by ultrasonic for 6 h continuously.     

贮氢合金Mm（NiCoMnAl）5的不同制备方法对MH/Ni电池性能的影响

研究了采用悬浮熔炼（常规铸态）和不同冷却速度的单辊快淬方法制备的Mm（NiCoMnAl）5型稀土系贮氢合金负极活性材料对金属氢化物镍（MH/Ni）电池性能的影响.结果表明,采用不同方法制备的合金对整个电池活化后的容量和内阻影响很小,但是常规铸态合金在退火后降低了电池的放电电压平台,快淬合金随着冷凝速率的提高,放电平台呈降低趋势.对循环充放电过程中电池内阻、循环到一定次数时负极贮氢合金的粒度和正极内铝含量的测试结果表明,铸态不退火合金较差的抗粉化性和较差的耐腐蚀性使电池的循环性能较差,经退火后其性能均有所提高,快淬合金使电池的循环性能优于常规铸态合金.     

贮氢合金Mm(NiCoMnAl)_5的不同制备方法对MH/Ni电池性能的影响

研究了采用悬浮熔炼(常规铸态)和不同冷却速度的单辊快淬方法制备的Mm(NiCoMnAl)5型稀土系贮氢合金负极活性材料对金属氢化物镍(MH/Ni)电池性能的影响。结果表明,采用不同方法制备的合金对整个电池活化后的容量和内阻影响很小,但是常规铸态合金在退火后降低了电池的放电电压平台,快淬合金随着冷凝速率的提高,放电平台呈降低趋势。对循环充放电过程中电池内阻、循环到一定次数时负极贮氢合金的粒度和正极内铝含量的测试结果表明,铸态不退火合金较差的抗粉化性和较差的耐腐蚀性使电池的循环性能较差,经退火后其性能均有所提高,快淬合金使电池的循环性能优于常规铸态合金。     

稀土-镁-镍基贮氢电极合金的研究进展

具有超结构特征的稀土-镁-镍基贮氢合金作为新一代金属氢化物/镍(MH/Ni)电池负极材料,因其高的放电容量和好的倍率放电性能,是目前贮氢电极合金发展的重点材料之一。本文从材料相结构、贮氢特性和电化学性能之间的关系出发,综述了近年来国内外稀土-镁-镍基AB3型、A2B7型和A5B19型贮氢电极合金的研究进展,为开发兼具高容量和长寿命的新型稀土系贮氢电极合金提供有价值的参考。     

Effects of compaction pressure on the electrochemical properties of Mm0.3Ml0.7Ni3.55Co0.75Mn0.4Al0.3 metal hydride electrodes

In this work, the negative electrodes of the nickel-metal hydride rechargeable batteries were prepared at different compaction pressures. The maximum discharge capacities and cycle stabilities of the electrodes were measured by means of electrochemical method. The crystal structures and surface morphologies of the alloys were intensively studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM) combined with energy-dispersive spectrometry (EDS), respectively. Based on these observations, the effects of compaction pressure on the electrochemical properties of the electrodes were systematically investigated. The results showed that the electrode prepared at a compaction pressure of 25 MPa exhibited the best discharge capacity and better cycle stability.     

Compositional optimization of vanadium-free hypo-stoichiometric AB2 metal hydride alloy for Ni/MH battery application

In an effort to reduce raw material cost and improve the charge retention characteristic of nickel metal hydride batteries, the Ti, Zr, and Ni-contents in vanadium-free AB₂ metal hydride alloys were optimized according to their capacity, charge retention, activation, high-rate capability, low-temperature performance, and cycle stability. A multi-component hypo-stoichiometric AB₂ alloy with a composition of Ti₁₀Zr₂₇Cr₈Mn₁₅Co₅Ni₃₅ was identified and compared to vanadium-containing AB₂ metal hydride alloys. Vanadium-free alloys provided better charge retention performance but with a trade-off in cycle life. The gaseous and electrochemical storage properties were correlated to both the average composition and the stoichiometry of the main AB₂ phases.     

Nanocrystalline LaNi4−xMn0.75Al0.25Cox electrode materials prepared by mechanical alloying (0≤x≤1.0)

Polycrystalline hydrogen storage alloys based on lanthanum (La) are commercially used as negative electrode materials for the nickel–metal hydride (Ni–MH_x) batteries. In this paper, mechanical alloying (MA) was used to synthesize nanocrystalline LaNi_4−xMn_0.75Al_0.25Co_x (x=0, 0.25, 0.5, 0.75 and 1.0) hydrogen storage materials. XRD analysis showed that, after 30 h milling, the starting mixture of the elements decomposed into an amorphous phase. Following the annealing in high purity argon at 700 °C for 0.5 h, XRD confirmed the formation of the CaCu₅-type structures with a crystallite sizes of about 25 nm. The nanocrystalline materials were used as negative electrodes for a Ni–MH_x battery. Cobalt substituting nickel in LaNi₄Mn_0.75Al_0.25 greatly improved the discharge capacity and cycle life of the LaNi₅ material. For example, in the nanocrystalline LaNi_3.75Mn_0.75Al_0.25Co_0.25 powder, discharge capacities up to 258 mA h g⁻¹ (at 40 mA g⁻¹ discharge current) were measured. Mechanical alloying is a suitable procedure to obtain LaNi₅-type alloy powders for electrochemical energy storage.     

Structural and electrochemical properties of TixZr7−xNi10

Simple ternary alloys with formula Ti_xZr_7−xNi₁₀ (x between 0 and 2.5) were studied as a potential replacement for Laves phase alloys used in the negative electrodes of nickel metal hydride batteries. The samples were prepared by arc-melting and were not annealed. The samples retained a high degree of disorder, which contributed positively to activation and other electrochemical properties. Before hydrogenation, the alloys have a Zr₇Ni₁₀ orthorhombic structure mixed with some C15 and ZrO₂ secondary phases. The amount of C15 secondary phase is important to the bulk diffusion of hydrogen and the surface electrochemical kinetics. That is, the diffusion coefficient and the exchange current both increase in the presence of C15 secondary phase. The proportion of C15 secondary phase is controllable by stoichiometry design. For instance, a slightly higher Zr content reduces the C15 content. Further, as the titanium substitution level increases: (1) the lattice constants decrease; (2) the PCT plateau pressure increases; (3) activation becomes easier; and (4) the high rate dischargeability improves.     

制备贮氢电池正极的工艺研究

采用正交试验方法研究了制备贮氢电池正极片的配方、导电剂、掺杂剂、添加剂、粘结剂以及制片压力等多种工艺因素对贮氢电池性能的影响,得到了制备贮氢电池正极片的最佳工艺条件：正极活性物质中添加３．０％～４．０％添加剂、１．０％～２．０％导电剂、２．０％～３．０％掺杂剂、复合粘结剂比例ＣＭＣ：ＰＴＦＥ＝０．２～０．６ ：１ ,制片压力为１０～１２ＭＰａ。研究发现：添加一定量的某 些掺杂剂如氧化钴等,可以有效地防止镍电极出现膨胀、脱落等现象,从而提高贮氢电池的循环寿命及自放电等性能。     

氧化物—空气半燃料电池用贮氢合金电极的烧结制备及其电化学特性

研究了应用在空气－氢化物半燃料电池上的制备配套金属氢化物厚型电极烧结技术，将贮氢合金与细镍粉和一定的添加剂形成浆料涂覆在泡沫镍基体，测试不同烧结参数对贮氢合金电极的电化学性能的影响，烧结电极合金的电化学活化特性和高倍率放电能力与传统的粘结式电极有较大的提高，为设计适合电动车用高能量密度空气－氢化物燃料电池，分别选用冲孔镍箔带，冲孔铜箔带和铜编织网作为集流体进行比较实验。结果表明，选定冲孔铜箔带是适宜于设计空气－氢化物燃料电池用厚型氢化物电极。     

Self-discharge mechanism of vanadium-titanium metal hydride electrodesfor Ni-MH rechargeable battery

In order to investigate the effect of the equilibrium hydrogen pressure (plateau pressure) of metal hydride (MH) alloys on self-discharge behavior, V₀₉Ti₀₁ alloys having multi-plateau pressures (the low and high plateau pressure) have been used as working electrodes in a half cell. A thermal desorption experiment and open-circuit potential monitoring were conducted to observe the self-discharge behavior of the electrodes. From the thermal desorption spectra of fully charged and discharged V₀₉Ti₀₁ electrodes (to-0.7 V vs. Hg/ HgO), it was found that only the high plateau pressure region from V₀₉Ti₀₁ electrodes is electrochemically useful in battery application. However, the open-circuit potential change and thermal desorption spectra of V₀₉Ti₀₁ electrodes after various open-circuit storage periods prove that self-discharge behavior is caused by hydrogen desorption from the low plateau pressure region (10^-8 atm) as well as the high plateau pressure region (0.1 atm). Therefore, it is suggested that the self-discharge behavior of V₀₉Ti₀₁ electrodes cannot be suppressed effectively by reduction of the plateau pressure of alloys through alloy modification.In addition, the pressure-composition-isotherms (P-C-T) of the low pressure region can be estimated by using the open-circuit potential corresponding to this region in Nernst’s equation.     

贮氢合金电极材料进展

简要综述贮氢合金电极材料三方面的最近进展 :(1)双相贮氢合金材料 ;(2 )复合贮氢电极材料 ;(3)镁基非晶及钠米晶贮氢电极材料。     

新型负极添加剂对MH/Ni电池性能的影响

用过渡金属氧化物作为ＭＨ／Ｎｉ电池的负极添加剂,研究了它对ＭＨ／Ｎｉ电池容量、放电电压、电池内压和循环性能的影响。加人２％的新型负极添加剂,可以在保证电池容量不受影响的前提下,使ＭＨ／Ｎｉ电池的放电中值电压升高约２０ｎＶ,以１Ｃ倍率电流充电时的最大电池内压减少０．４ＭＰＡ,并显著提高电池循环性能。以１Ｃ倍率快速充放测试徨４００次时,其容量保持率在９０％以上,放电中值电压变１．２１６Ｖ。     

BASIC ELECTROLYTIC METHOD FOR RECOVERY OF LEAD FROM SCRAP BATTERIES

ＢＡＳＩＣＥＬＥＣＴＲＯＬＹＴＩＣＭＥＴＨＯＤＦＯＲＲＥＣＯＶＥＲＹＯＦＬＥＡＤＦＲＯＭＳＣＲＡＰＢＡＴＴＥＲＩＥＳ￥ＣｈｅｎＷｅｉｐｉｎｇ；ＴｉａｎＹｉｚｈｕａｎｇ；ＢｉａｎＫｅｊｕｎ；ＺｈｅｎｇＹｕｅ（ＩｎｓｔｉｔｕｔｅｆｏｒＥｎｖｉｒｏｎｍｅｎ...     

Grid alloys for automobile batteries in the new millennium

By 2000, most lead-acid, starting/lightening/ignition (SLI) batteries produced in the Western world had made the transition from traditional lead-antimony alloy grids to lead-calcium-based alloys. The automobile requirements for high cranking performance and maintenance-free batteries have accelerated the trend. Cost reductions as well as high numbers of grids-per-battery have led to automated, continuous grid-manufacturing processes which require lead-calcium-based alloys. Higher under-hood temperatures have lead to the introduction of higher tin content and silver additions to lead-calcium alloys to improve battery life. Lead-antimony alloys are still used as grid alloys in SLI batteries around the world. With higher performance requirements in vehicles and newer batteries in the next decade, however, the use of lead-antimony alloys for automobile batteries may decline significantly. This paper describes the operating conditions of automobile batteries in the new millennium and how the grid-production processes and grid alloys have changed to meet the requirements of these batteries. For more information, contact Andreas Siegmund, RSR Technologies, 2777 Stemmons Freeway, Suite 1800, Dallas, Texas 75207; (214) 583-0359; fax (214) 631-6092; e-mail asiegmund@rsrtechnologies.com.     

Gas atomization of Cu-modified AB5 metal hydride alloys

Gas atomization together with a hydrogen annealing process has been proposed as a method to achieve improved low-temperature performance of AB₅ alloy electrodes in Ni/MH batteries and restore the original cycle life which was sacrificed by the incorporation of copper in the alloy formula. While the gas atomization process reduces the lattice constant aspect ratio c/a of the Cu-containing alloys, the addition of a hydrogen annealing step recovers this property, although it is still inferior to the conventionally prepared annealed Cu-free alloy. This observation correlates very well with the cycle life performance. In addition to extending the cycle life of the Cu-containing metal hydride electrode, processing by gas atomization with additional hydrogen annealing improves high-rate, low-temperature, and charge retention performances for both Cu-free and Cu-containing AB₅ alloys. The degradation mechanisms of alloys made by different processes through cycling are also discussed.     

镀镍石墨粉的电化学性质

利用化学镀方法在石墨粉表面镀覆了一层均匀、完整的金属镍,研究了镀镍石墨粉电极及镀镍石墨粉作为ＭＨ／Ｎｉ电池镍电极导电剂时的电化学性质。实验表明,石墨粉表面镀覆金属镍可增另其电化学活性;用镀镍石墨粉作为电极导电剂时,可以改善镍电极的导电性能,降低电池内阻,提高正极活性物质的利用率,且电池的循环稳定性好,以１Ｃ倍率充放电循环１２０就衰减。     

Review on Comprehensive Recovery of Valuable Metals from Spent Electrode Materials of Nickel-Hydrogen Batteries

在废电池中含有大量有价金属,如镍、钴、稀土元素等。从废电池材料中回收有价金属不仅能保护环境,还能利用资源并能降低电池生产成本。与其他电池类似,任意丢弃废镍氢电池将导致严重污染,因而从废弃镍氢电池中回收有价金属的意义重大。本文综述了废弃镍氢电池回收问题,并详细介绍了几种回收技术。此外,展望了从镍氢电池废弃电极材料中综合回收有价金属的前景。     

Effect of surface modification of metal hydride electrode on performance of MH/Ni batteries

A novel method was applied to the surface modification of the metal hydride(MH)electrode of MH/Ni batteries.Both sides of the electrode were plated with a thin silver film about 0.1μm thick using vacuum evaporation plating technology,and the effect of the electrode on the performance of MH/Ni batteries was examined.It is found that the surface modification can enhance the electrode conductivity and decrease the battery ohimic resistance.After surface modification,the discharge capacity at 5C(7.5A)is increased by 212 mA.h and the discharge voltage is increased by 0.11 V,the resistance of the batteries is also decreased by 32%.The batteries with modified electrode exhibit satisfactory durability.The remaining capacity of the modified batteries is 89%of the initial capacity even after 500 cycles.The inner pressure of the batteries during overcharging is lowered and the charging efficiency of the batteries is improved.