CoO AS ADDITIVE IN POSITIVE ELECTRODE OF NICKEL-METAL HYDRIDE BATTERY

A series of positive electrodes for Ni/MH battery were fabricated by addition of CoO.The morphology and microstructure of the electrodes were examined by SEM and EDS, and electrochemical behavior was investigated in three-compartment appliances at room temperature.The electrochemical performance of the positive electrodes with CoO was improved. Under the same charge-discharge cycle, the electrodes with CoO showed higher specific capacity, lower charge mean voltage and higher discharge mean voltage. But ...

Surface behavior of pasted nickel electrodes with electrodeposited Co-Ce on substrate

MH/Ni battery for electro-vehicle has become a hot topic of studies. The Co-Ce alloys were electrodeposited on the nickel substrate to modify pasted nickel electrode substrate. SEM and XRD results show that the surface of the substrate contains Co(OH)2 and CoOOH film, and CV shows that modified film can improve electron conductivity capability. The state of charge (SOC) or state of discharge (SOD) curves indicate that Co-Ce modified substrate can enhance Ni electrode charge and discharge performance at high rate. The surface analysis by XPS shows that, the Co(Ⅱ)/Co(Ⅲ) ratio is 76.80/23.19 at the SOD, but the Co(Ⅱ)/Co(Ⅲ) ratio is 57.79/42.21 at the SOC, which indicates that the conductibility of electrodeposited Co-Ce alloys on the nickel substrate is enhanced because CoOOH and Co(OH)2 are created on the substrate surface. The modified surface with CoOOH and Co(OH)2 can enhance the conductibility of electrons between the substrate and active materials, and improve the high rate SOC and SOD ability.

Effects of flaky rare earth oxide additives on the high temperature performance of nickel electrodes

Effects of flaky rare earth oxide additives including Er2O3,Tm2O3,and Yb2O3,Lu2O3 on high temperature and high rate discharge performance of nickel electrodes were investigated.The discharge efficiency at 0.2C reached 96% at 60 oC for electrodes with 1 at.% flaky rare earth oxides.The high rate discharge performance for electrodes with flaky rare earth oxides were improved significantly,for example,discharge efficiency at 5C improved from 50% to 70%.The results showed that the end charging potential of the ...

Valence modulated nickel oxynitride network as integrated bifunctional electrodes for enhanced energy storage

As promising electrode materials,transition metal oxides have attracted considerable attention owing to their excellent performance in electrochemical energy storage.However,their poor conductivity and fragile structure limit their practical application.In this study,a binder-free nickel oxide/oxynitride network(NiON WS)bifunctional electrodes with cation multivalent states that exhibit high energy storage performance were synthesized for the first time.The massive active sites,high specific surface areas,and multiple cation valence states of NiON WS were advantageous for electrochemical redox reaction during its application in supercapacitors(1283.5 mF cm^(-2))and lithium-ion batteries(1345.0 mA h g^(-1)).Particularly,the NiON WS based flexible asymmetric SCs exhibit excellent capacitance and energy densities.First-principle calculations were employed to study the mechanism of the electrochemical performance improvement of NiON WS.This study demonstrates the potential of transition metal oxides electrode with high capacity and activity for electrochemical energy storage and conversion.

Electrochemical performance of a nickel-rich LiNi0.6Co0.2Mn0.2O2 cathode material for lithium-ion batteries under different cut-off voltages

A spherical-like Ni0.6Co0.2Mn0.2(OH)2precursor was tuned homogeneously to synthesize LiNi0.6Co0.2Mn0.2O2as a cathode material for lithium-ion batteries. The effects of calcination temperature on the crystal structure, morphology, and the electrochemical performance of the as-prepared LiNi0.6Co0.2Mn0.2O2were investigated in detail. The as-prepared material was characterized by X-ray diffraction, scanning electron microscopy, laser particle size analysis, charge–discharge tests, and cyclic voltammetry measurements. The results show that the spherical-like LiNi0.6Co0.2Mn0.2O2material obtained by calcination at 900°C displayed the most significant layered structure among samples calcined at various temperatures, with a particle size of approximately 10 μm. It delivered an initial discharge capacity of 189.2 mAh•g−1at 0.2C with a capacity retention of 94.0% after 100 cycles between 2.7 and 4.3 V. The as-prepared cathode material also exhibited good rate performance, with a discharge capacity of 119.6 mAh•g−1at 5C. Furthermore, within the cut-off voltage ranges from 2.7 to 4.3, 4.4, and 4.5 V, the initial discharge capacities of the calcined samples were 170.7, 180.9, and 192.8 mAh•g−1, respectively, at a rate of 1C. The corresponding retentions were 86.8%, 80.3%, and 74.4% after 200 cycles, respectively. © 2017, University of Science and Technology Beijing and Springer-Verlag Berlin Heidelberg.

A critical review on nickel-based cathodes in rechargeable batteries

The 3d transition-metal nickel(Ni)-based cathodes have long been widely used in rechargeable batteries for over 100 years,from Ni-based alkaline rechargeable batteries,such as nickel-cadmium(Ni-Cd)and nickel-metal hydride(Ni-MH)batteries,to the Ni-rich cathode featured in lithium-ion batteries(LIBs).Ni-based alkaline batteries were first invented in the 1900s,and the well-developed Ni-MH batteries were used on a large scale in Toyota Prius vehicles in the mid-1990s.Around the same time,however,Sony Corporation commercialized the first LIBs in camcorders.After temporally fading as LiCoO_(2) dominated the cathode in LIBs,nickel oxide-based cathodes eventually found their way back to the mainstreaming battery industry.The uniqueness of Ni in batteries is that it helps to deliver high energy density and great storage capacity at a low cost.This review mainly provides a comprehensive overview of the key role of Ni-based cathodes in rechargeable batteries.After presenting the physical and chemical properties of the 3d transition-metal Ni,which make it an optimal cationic redox center in the cathode of batteries,we introduce the structure,reaction mechanism,and modification of nickel hydroxide electrode in Ni-Cd and Ni-MH rechargeable batteries.We then move on to the Ni-based layered oxide cathode in LIBs,with a focus on the structure,issues,and challenges of layered oxides,LiNiO_(2),and LiNi_(1−x−y)Co_(x)Mn_(y)O_(2).The role of Ni in the electrochemical performance and thermal stability of the Ni-rich cathode is highlighted.By bridging the“old”Ni-based batteries and the“modern”Ni-rich cathode in the LIBs,this review is committed to providing insights into the Ni-based electrochemistry and material design,which have been under research and development for over 100 years.This overview would shed new light on the development of advanced Ni-containing batteries with high energy density and long cycle life.

Improvement of thickness deposition uniformity in nickel electroforming for micro mold inserts

Thickness deposition is a crucial issue on the application of electroformed micro mold inserts. Edge concentration effect is the main source of the non-uniformity. The techniques of adopting a non-conducting shield, a secondary electrode and a movable cathode were explored to improve the thickness deposition uniformity during the nickel electroforming process. Regarding these techniques, a micro electroforming system with a movable cathode was particularly developed. The thickness variation of a 16 mm×16 mm electroformed sample decreased respectively from 150% to 35%, 12% and 18% by these three techniques. Combining these validated methods, anickelmold insert for microlens array was electroformed with satisfactory mechanical properties and high replication precision. It could be applied to the following injection molding process.

Improved electrochemical hydrogen storage properties of Mg-Y thin films as a function of substrate temperature

Pd-capped Mg78Y22 thin films have been prepared by direct current magnetron co-sputtering system at different substrate temperatures and their electrochemical hydrogen storage properties have been investigated.It is found that rising substrate temperature to 60 ℃ can coarsen the surface of thin film,thus facilitating the diffusion of hydrogen atoms and then enhancing its discharge capacity to 1725 mAh·g-1.Simultaneously,the cyclic stability is effectively improved due to the increased adhesion force between film and substrate as a function of temperature.In addition,the specimen exhibits a very long and flat discharge plateau at about —0.67 V,at which nearly 60%of capacity is maintained.The property is favorable for the application in metal hydride/nickel secondary batteries.The results indicate that rising optimal substrate temperature has a beneficial effect on the electrochemical hydrogen storage of Mg-Y thin films.

ELECTRODE CHARACTERISTICS OF NANOCRYSTALLINE LaNi_5 PREPARED BY MECHANICAL ALLOYING

ＥＬＥＣＴＲＯＤＥＣＨＡＲＡＣＴＥＲＩＳＴＩＣＳＯＦＮＡＮＯＣＲＹＳＴＡＬＬＩＮＥＬａＮｉ５ＰＲＥＰＡＲＥＤＢＹＭＥＣＨＡＮＩＣＡＬＡＬＬＯＹＩＮＧ①ＣｈｅｎＺｈｅｎｈｕａ，ＣｈｅｎＺｈａｏｈｕｉ，ＺｈｏｕＤｕｏｓａｎａｎｄＨｕａｎｇＰｅｉｙｕｎＩｎ...

Effects of Annealing Temperature on Microstructure and Electrochemical Properties of Perovskite-type Oxide LaFeO3 as Negative Electrode for Metal Hydride/Nickel（MH/Ni） Batteries

We reported the effects of annealing temperatures on microstructure and electrochemical properties of perovskite-type oxide LaFeO3 prepared by stearic acid combustion method. X-Ray diffraction（XRD） patterns show that the annealed LaFeO3 powder has orthorhombic structure. Scanning electron microscopy（SEM） and transmission electron microscopy（TEM） images show the presence of homogeneously dispersed, less aggregated, and small crystals（30--40 nm） at annealing temperatures of 500 and 600 ℃. However, as the annealing temperature was increased to 700 and 800 ℃, the crystals began to combine with each other and grew into further larger crystals（90--100 nm）. The electrochemical performance of the annealed oxides was measured at 60 ℃ using chronopotentiometry, potentiodynamic polarization, and cyclic voltammetry. As the annealing temperature increased, the discharge capacity and anti-corrosion ability of the oxide electrode first increased and then decreased, reaching the optimum values at 600 ℃, with a maximum discharge capacity of 563 mA-h/g. The better electrochemical performance of LaFeO3 annealed at 600℃ could be ascribed to their smaller and more homogeneous crysals.

高镍三元材料的高压稳定性研究进展

高镍三元材料LiNixMnyCo_(1-x-y)O_(2)(NCM)具有可逆容量大、工作电压高等优点,已成为锂离子电池的理想正极材料。然而,为满足远程电动汽车的需求,动力电池能量密度需达到400 Wh/kg,这是现有NCM材料无法实现的。提高截止电压是获得更高比容量的有效手段,有望满足能量密度需求。但是高截止电压会导致电化学性能的快速衰减。为了更好地提高高镍材料在高压下的稳定性,本文简述了高镍材料在高压下的性能衰减机理,重点总结了现有各种改性策略的研究进展,以及对NCM材料电化学性能的作用机理,展望其未来发展趋势和应用前景。

废旧锂电池极片热解试验研究

废旧锂电池作为一种二次资源,蕴藏巨大的回收价值。本文结合其主要成分热解性质,开展废旧锂电池极片的热解试验。废弃锂电池破碎分选后,正负极片热解过程的主要影响因素有温度、时间、真空度和气氛等。试验结果表明,热解温度为400℃,热解时间为0.75 h时,真空和氮气气氛可获得良好的热解效果,黑粉产率为75%~78%,镍、钴、锰等主要金属的回收率大于95%。

高容量泡沫式镍电极的研制

本文介绍了一种高容量泡沫式镍电极,确定了电极的工艺参数,考察了由其作为正极的圆柱密封氢镍电池的性能。

锂离子电池中贵重金属的回收

新型储能器件锂离子二次电池的正极材料中含有大量的钴 ,镍等贵重金属元素 ,尝试将传统的络合法与离子交换法相结合 ,实现了对材料中的多种金属元素的分离和回收 ,其中钴镍两种金属的回收率分别达到了 84.9%和 89.1%,工艺流程简单 ,是一种可行的回收工艺 。

镍电极研究进展

碱性镍蓄电池中镍正极的研究和应用已有一个世纪的历史 ,无论在理论研究还是实际应用上都取得了长足的进步。近些年随着MH Ni电池的成功开发和应用 ,作为MH Ni电池中容量限制电极的镍电极又受到人们的极大关注。综述了镍电极活性物质的结构和物理化学性质 ,氢氧化镍的制备 ,镍电极的热力学与动力学 ,镍电极添加剂和制备工艺方面的研究、应用和发展状况。在应用方面重点综述了镍电极添加剂 。

镍纳米线电极的交流阻抗研究

用交流阻抗法研究了一种新型电极——镍纳米线电极在碱性溶液中的电化学行为 ,给出了相应的等效电路和拟合结果 .实验结果表明 ,外加电位对电极表面化学反应速度和类型有显著影响 .在外加电位不高时 ,Ni( )氧化成 Ni( )的电化学过程随着电位的升高而明显加速 ;当外加电位高于 0 .40 V以后 ,电极表面同时发生电化学析氧反应 .相同条件下 。

MH-Ni电池失效简析(Ⅰ)——镍电极的膨胀

高密度球形Ｎｉ（ＯＨ）２的开发，大大地提高了镍电极的体积比能量。但其比表面积低，在应用于ＭＨ－Ｎｉ电池时要求镍电极能符合快速充放电的要求，电流密度成倍增加，使镍电极发生膨胀。本文通过解剖早期失效及寿命终止的电池，研究了镍电极膨胀对它的作用与影响。镍电极膨胀吸液，使隔膜含液量降低，增大了电池欧姆极化引起电池早期失效。镍电极的膨胀不仅会使ＭＨ电极含液量降低，加速合金的氧化粉化，还可能因其复合氧能力下降，使电池内压升高造成电解液的进一步流失而导致电池性能进一步恶化。实验通过ＳＥＭ、ＸＲＤ等测试表明，镍电极本身也会因膨胀造成整体导电网络的破坏与改变。两电极劣化的共同作用导致氢镍电池的失效。

高比容量中空纤维镍电极的研究

用传统工艺方法制备出含有中空纤维的多孔镍基板,基板孔率由72%～76%增加到85%～88%(含骨架).借助电化学浸渍法制得性能良好的含纤维镍正极,其中浸钴电极比容量可达173.7mAh/g、555.8mAh/cm^3和41.7mAh/cm^2.

发泡式镉镍电池的研制

本文介绍了发泡式镉镍电池的研制情况。对发泡式镍基板、发泡式电极与电池的制造工艺及其特点作了较详细的说明。研制的AA型发泡式镉镍电池性能优良,放电容量为700mAh以上,可用1.5小时快速充电,循环寿命超过400次。

β-NiOOH的研究(Ⅱ)电极充放电反应机理

以 β Ni(OH) 2 为原料采用温和化学氧化法合成 β NiOOH ,利用交流阻抗技术、恒电位阶跃技术和循环伏安技术对合成产物的电极反应机理进行了研究 ,认为 β NiOOH还原过程中含有一吸附过程 ,而 β Ni(OH) 2 氧化过程中不含有吸附过程 ,且反应 β NiOOHβ Ni(OH ) 2 为一准可逆反应过程。利用恒电位阶跃技术测定了模拟电极的质子扩散系数 ,充电态 β NiOOH中质子扩散系数为 3 .2× 10 -9cm2 ·s-1,而放电态 β Ni(OH ) 2 中质子扩散系数为 1.4× 10 -12cm2 ·s-1。