一种球形氢氧化镍材料及其制备方法

本发明提供了一种超级电容器用球形氢氧化镍电极材料及其制备方法。该制备方法包括:以(0.3~10)∶1的体积比将硝酸镍水溶液与丙三醇混合,加入尿素,混合、反应、除杂、干燥,即得由纳米片组装而成的球形氢氧化镍电极材料。     

掺锰氢氧化镍的合成及性能研究

氢氧化镍广范应用于镍系列二次碱性电池正极材料中,镍电极的容量是制约其发展的一个重要因素。通过共沉淀法制备了掺杂锰的氢氧化镍。研究表明,掺杂锰元素可以形成同时存在α-Ni(OH)2和β-Ni(OH)2的混合晶体结构,镍电极容量提高到303mAh/g,镍电极的膨胀率降低,是一种前景广阔的正极材料。     

镍电极活性材料性能的分析方法

镍电极活性材料的物理、化学、结构性能与电化学性能之间存在着密切的关系,化学组成、密度、粒径大小、微观结构及电化学性能等是表征镍氢电池正极材料氢氧化镍性能的参数。本文简单介绍了球形氢氧化镍的性质并综述了其性能参数的分析检测方法。     

化学浴法制备氢氧化镍@生物质炭纤维纳米复合材料及其电化学性能研究

以棉花在惰性气氛下高温处理得到的生物质炭纤维为载体,采用化学浴法原位制备氢氧化镍@生物质炭纤维纳米复合材料,并研究其作为超级电容器电极材料的电化学性能。借助X射线衍射和扫描电镜表征手段研究材料的结构和形貌。采用循环伏安、恒电流充放电及交流阻抗等电化学测试方法对材料的电化学性能进行分析。结果表明,氢氧化镍@生物质炭纤维复合材料中的氢氧化镍以纳米片层结构生长在生物质炭纤维表面,形成以氢氧化镍纳米片为壳、生物质炭纤维为核的核壳式结构;生物质炭纤维的引入能有效改善氢氧化镍的分散性,降低材料的电子转移阻力,进而提高氢氧化镍@生物质炭纤维复合材料的电化学性能。     

掺锰氢氧化镍的合成工艺探究

α相氢氧化镍由于其高放电容量倍受研究者的关注。以Mn作为掺杂元素,在保护气氛下合成了一系列含α相氢氧化镍电池材料,研究了不同掺Mn量及搅拌速度对配位沉淀法合成工艺的影响。用正交试验筛选出合成工艺参数的范围,再通过均匀设计法进一步优化得到最佳的工艺参数:掺锰量为13.3%,搅拌速度为32 r/S,pH为12.5,放电容量达到300 mAh/g,明显高于市售氢氧化镍产品,对含α相氢氧化镍电池材料工业化生产具有一定的指导意义。     

材料专利文摘

一种铝基非晶 /纳米复相材料的制备方法【公告号】 14 31334　　　　【公告日】 2 0 0 3- 0 7- 2 3本发明属于金属材料领域 ,涉及了一种高强度低密度的铝基非晶 /纳米复相材料及其制备方法 ,该铝基非晶 /纳米复相材料的特征是 :各组分的原子百分比为 :镍 8%～10 % ,镧 1 5 %～ 2 1% ,铈 2 2 %～ 4 % ,镨 0 1%～0 8% ,钕 0 2 %～ 1 1% ,铝为余量。在经液氮冷却的铜模喷铸条件下可以制出铝基非晶 /纳米复相材料。利用本发明所制备的合金具有高的非晶与纳米晶形成能力 ,且性能优良。纳米粉体材料紫外屏蔽性能评估方法【公告号】 14 314 81…     

Ni(OH)2/活性炭复合材料在超级电容器中的应用

用化学沉淀法在活性炭(AC)表面和微孔内掺杂不同量的氢氧化镍,制备了氢氧化镍-活性炭[Ni(OH)2-AC]复合材料. 用X射线衍射(XRD)和氮气吸附等温线等对活性炭和复合材料进行表征,结果表明,所制材料为b-Ni(OH)2-AC复合材料. 对不同掺杂量的b-Ni(OH)2-AC复合材料的电化学性能进行了研究,循环伏安、恒流充放电实验表明,少量氢氧化镍掺入活性炭表面和微孔中,所得材料的比电容较活性炭有所提高,并具有良好的充放电性能;当氢氧化镍的掺入量为6%(w)时,所制备的超级电容器单电极表现出优良的电化学性能. 以活性炭电极作负极,复合材料作正极制成复合型超级电容器,循环性能测试发现,掺入6%(w)氢氧化镍的复合材料制成的Ni(OH)2-AC/AC复合型超级电容器比电容高达330.7 F/g,比活性炭(AC/AC)超级电容器比电容(245.6 F/g)提高了34.6%,且Ni(OH)2-AC/AC复合型超级电容器具有更好的循环充放电性能.     

非晶态氢氧化镍复合碳纳米管电极材料的电化学性能

采用快速冷冻化学共沉淀法制备非晶态Ni(OH)2粉体,将其作为电化学活性物质复合碳纳米管合成镍电极材料,研究了其电化学性能. 结果表明,加入碳纳米管有效减少了镍电极的电荷转移电阻,增大了电极反应过程的质子扩散系数. 复合0.5%(w)碳纳米管合成的非晶态氢氧化镍电极材料在1 C充放电制度下,放电终止电压为1.0 V时,其放电比容量高达336.5 mA×h/g,放电中值电压为1.251 V,充放电循环30次,放电比容量保持率为96.74%,表现出较好的高倍率充放电性能.     

纳米氢氧化镍制备的最新进展

纳米材料由于其颗粒较小,因此其性能和常规材料相比有较大的改变.随着纳米材料科学技术的迅猛发展,纳米材料的研究逐渐扩展到化学电源领域.氢氧化镍作为Ni-MH二次电池的主要正极活性材料,对电池的容量和寿命起着关键性的作用.但是目前传统方法制备的氢氧化镍容量较低,远没有达到其理论值.随着将纳米材料制备技术引入到氢氧化镍的合成,使其比容量有了质的提升,合成纳米氢氧化镍也成为研究的热点.介绍了纳米材料的一般性知识,同时阐述了纳米氢氧化镍作为Ni-MH电池的正极活性材料所具有的特性和制备方法上的最新进展,以及在制备和应用方面出现的一些问题.     

球形氢氧化镍的制备及其电化学性能研究

为了考察Ni(OH)_2颗粒粒径与形貌对镍电极性能的影响,利用超声波沉淀法制备出了粒径小且分布均匀的球形氢氧化镍,研究了反应体系中超声波强度对氢氧化镍颗粒形貌的影响。利用扫描电子显微镜(SEM)、X射线衍射仪(XRD)、粒度分析、循环伏安特性曲线、倍率充放电技术对制备的氢氧化镍材料进行表征与测试。结果表明,超声波强度对氢氧化镍颗粒形貌有显著影响,实验确定适宜的超声波强度在216 W左右;粒度分析显示制备的球形氢氧化镍颗粒粒度在10μm左右。XRD测试证明制备的氢氧化镍为β-Ni(OH)_2;循环伏安特性曲线和倍率充放电测试发现,该材料具有良好的循环保持率,在0.4 C充电3 h,静置3 min,1 C放电至1.2 V的测试条件下循环30次后循环保持率为89%,最大放电比容量达260 m Ah/g。     

稀土La(Ⅲ)掺杂非晶态氢氧化镍的电化学性能

采用微乳液快速冷冻沉淀法制备出稀土La(Ⅲ)掺杂非晶态Ni(OH)2粉体材料,对样品粉体的微结构及形态进行了表征分析,同时将样品作为活性物质合成电极材料,组装成碱性MH-Ni模拟电池,测试其电化学性能。结果表明,掺杂6%La(Ⅲ)样品材料微结构无序性强,质子缺陷较多。将所制备的样品在80 mA/g恒电流充电5.5 h,40 mA/g恒电流放电,终止电压为1.0 V的充放电制度下,其放电平台达到1.256 V,放电比容量为317.1 mAh/g,充放电循环30次放电比容量衰减仅为3.943%,具有较好的电化学稳定性和循环可逆性。     

非晶态Ni(OH)2电极材料的制备工艺

采用微乳液快速冷冻沉淀法制备非晶态Ni(OH)2. 通过单因素及正交实验研究反应体系的pH值、反应温度和时间等因素对制备的非晶态Ni(OH)2电化学性能的影响. 结果表明,主要影响因素为pH值,其次为反应温度和时间. 采用TX-100/正丁醇/环己烷/水体系,控制TX-100与正丁醇的体积比为1:15,W值(水与表面活性剂质量比)为15.1,pH为12,反应时间2 h,反应温度55℃的条件下进行反应,放入0~5℃的超低温恒温槽中快速冷冻沉淀,合成出Ni(OH)2非晶相粉体电极活性材料,该材料的放电比容量达333.22 mA×h/g,具有较高的电化学容量. 初步探讨了微乳液快速冷冻沉淀法制备非晶态Ni(OH)2粉体的作用机理.     

The nickel–carbon asymmetric supercapacitor—Performance,energy density and electrode mass ratios

The performance of nickel hydroxide/carbon asymmetric supercapacitors has been studied with a range of positive and negative active material ratios. The utilisation of the nickel hydroxide electrode in asymmetric supercapacitors was found to be a function of the mass ratio of the positive and negative electrode materials and not independent as previously assumed. Previous models describing the behaviour of asymmetric supercapacitors assumed that the voltage swing was entirely due to the polarisable electrode. These models were found to be inadequate for describing the rate dependant charge/discharge behaviour of asymmetric supercapacitors. The mass ratio of the active materials was determined to be an important factor in predicting the observed behaviour and has been incorporated into an improved model.     

A facile preparation of 3D flower-shaped Ni/Al-LDHs covered by β-Ni(OH)2 nanoplates as superior material for high power application

In the present study, we propose a novel electrode material of β-nickel hydroxide covering nickel/aluminum layered double hydroxides via a facile complexation-precipitation method. The as-obtained materials with 3-dimensional nanostructures are further utilized as highly capable electrode material in nickel-metal hydride batteries. The electrochemical test results demonstrated the β-nickel hydroxide covering nickel/aluminum-layered double hydroxides with 28% of β-nickel hydroxide provided a superior specific capacity value of 452 mA·h·g^-1 in a current density of 5 A·g^-1 using 6 M KOH as electrolyte as compared with other materials. In addition, the optimized sample displays an outstanding cyclic stability along with a huge specific capacity value of 320 mAh·g^-1, and very small decay rate of 3.3% at 50 A·g^-1 after 3000 cycles of charge/discharge test. These indicate that the newly designed material with nanostructures not only provides an efficient contact interface between electrolyte and active species and facilitates the transport of electrons and ions, but also protects the 3-dimensional nickel/aluminum layered double hydroxides, achieving a high specific capacity, fast redox reaction and excellent long-term cyclic stability. Therefore, the β-nickel hydroxide covering nickel/aluminum layered double hydroxides with superior electrochemical performance is predictable to be a gifted electrode material in nickel-metal hydride batteries.     

High temperature performances of yttrium-doped spherical nickel hydroxide

The regular and yttrium-doped spherical β-phase nickel hydroxides were synthesized by means of chemically co-precipitation. The yttrium-doping with long needle-like nanocrystallites observed by TEM promoted the formation of the spherical nickel hydroxide with the larger diameter of about 5 μm. The discharge capacity of the yttrium-doped spherical nickel hydroxide was measured to be slightly lower than that of the regular spherical nickel hydroxide at room temperature. At temperatures of above 50 °C, however, the discharge capacity of the yttrium-doped nickel hydroxide is much higher than that of the regular spherical nickel hydroxide. The improvement of discharge capacity at elevated temperatures was contributed to the increase of the charge acceptance of yttrium-doped nickel hydroxide. The formation of an yttrium-rich surface layer on nickel hydroxide particles raised the oxygen evolution over-potential, leading to performance improvements of the nickel hydroxide electrode. The improvement of high temperature charge acceptance of yttrium-doped nickel hydroxide remarkably contributed to the high temperature charge-discharge efficiency of the nickel-metal hydride (Ni-MH) batteries with a commercial AAA size.     

Dynamic monitoring of structural changes in nickel hydroxide electrodes during discharge in batteries

The nickel hydroxide electrode is used as the positive plate of many rechargeable battery systems such as the nickel/cadmium, nickel/hydrogen, and nickel/metal hydrides. The electrochemical energy storage in the nickel hydroxide electrodes is related to the reversible characteristics of the redox couple nickel hydroxide/ox hydroxide. In the present work we describe the use of the electrochemical impedance spectroscopy (EIS) technique as a tool to characterize the dynamic behaviour of nickel hydroxide electrodes at different states of discharge (SOD) in KOH 7 M electrolytic solutions. The parameter identification procedure allows the estimation of the active area per unit volume, the solution conductivity as well as diffusion and kinetic constants related to the process, that represent very important parameters to evaluate the electrode performance.     

Electrode material and performance of amorphous Ni(OH)2 codoped by Fe(Ⅲ) and Al(Ⅲ)

采用快速冷冻沉淀法首次成功制备出Fe(Ⅲ)和Al(Ⅲ)复合掺杂非晶态Ni(OH)₂粉体材料。通过XRD、SAED、SEM、IR、Raman光谱及DSC-TG等对样品粉体的结构形态进行表征和分析,同时将样品合成电极材料并组装成MH/Ni模拟电池进行电化学性能测试,结果表明,样品材料内部结构缺陷多、无序性强、材料微粒大小比较均匀,并具有较好的分散性,结合水含量较多。将复合掺杂Fe(Ⅲ) 5%和Al(Ⅲ) 8%的样品材料制备镍正极并组装成MH/Ni模拟电池,在以80 mA·g^-1恒流充电5.5 h,40 mA·g^-1恒流放电,终止电压1.0 V的充放电制度下,进行充放电性能、比容量及其循环性能等电化学性能的测试,放电平台平稳,工作电压高达1.30 V,放电比容量达到357.6 mAh·g^-1,且在电极过程中材料的稳定性增强、电化学阻抗较小,循环可逆性较好。     

Fe(Ⅲ)和Al(Ⅲ)复合掺杂非晶态Ni(OH)2的电极材料及性能

采用快速冷冻沉淀法首次成功制备出Fe(Ⅲ)和Al(Ⅲ)复合掺杂非晶态Ni(OH)₂粉体材料。通过XRD、SAED、SEM、IR、Raman光谱及DSC-TG等对样品粉体的结构形态进行表征和分析,同时将样品合成电极材料并组装成MH/Ni模拟电池进行电化学性能测试,结果表明,样品材料内部结构缺陷多、无序性强、材料微粒大小比较均匀,并具有较好的分散性,结合水含量较多。将复合掺杂Fe(Ⅲ) 5%和Al(Ⅲ) 8%的样品材料制备镍正极并组装成MH/Ni模拟电池,在以80 mA·g^-1恒流充电5.5 h,40 mA·g^-1恒流放电,终止电压1.0 V的充放电制度下,进行充放电性能、比容量及其循环性能等电化学性能的测试,放电平台平稳,工作电压高达1.30 V,放电比容量达到357.6 mAh·g^-1,且在电极过程中材料的稳定性增强、电化学阻抗较小,循环可逆性较好。     

Ca3(PO4)2 coating of spherical Ni(OH)2 cathode materials for Ni-MH batteries at elevated temperature

Calcium phosphate was used for surface modification of spherical nickel hydroxide to improve its high temperature performance at the first time due to its low cost. The Ca₃(PO₄)₂ and Co(OH)₂ coated nickel hydroxides were prepared by precipitation of Ca₃(PO₄)₂ on the surface of spherical nickel hydroxide, followed by precipitation of Co(OH)₂ on its surface. The optimum coating content of calcium was around 2% (atomic concentration) to obtain high discharge capacity both at 25 and 60 °C. It was shown that the discharge capacity of nickel hydroxide at higher temperatures was improved by coating of Ca₃(PO₄)₂ and cobalt hydroxide. The high temperature performances of the sealed AA-sized nickel-metal hydride (Ni-MH) batteries using Ca/Co coated nickel hydroxide as positive electrodes were carried out, showing much better than those using uncoated or only Co(OH)₂ coated nickel hydroxide electrodes. The charge acceptance of the battery using 2% Ca and 2% Co coated nickel hydroxide reached 81% at 60 °C, where the charge acceptances for uncoated and only Co(OH)₂ coated nickel hydroxide were only 42 and 48%, respectively. It has shown that the Ca/Co coating is an effective way to improve the high temperature performance of nickel hydroxide for nickel-metal hydride batteries. It is a promising cathode material of Ni-MH batteries for EV applications due to the cost.     

Nickel and Lanthanum Hydroxide Nanocomposites with Much Improved Electrochemical Performance for Supercapacitors

By developing a facile low temperature hydrothermal process, we demonstrate the direct growth of nickel and lanthanum hydroxide nanocomposites on Ni‐foam substrate. The hydroxide nanocomposites thus derived show much enhanced overall electrochemical capacitance and improved stability of the alpha nickel hydroxide phase in alkaline solution. By adjusting the initial molar ratio between nickel and lanthanum nitrates from 1:0 to 1:2, the electrochemical behavior, such as specific capacitance, shows a dramatic change, while the nickel hydroxide phase evolves from beta nickel hydroxides (1:0) to alpha nickel hydroxide (1:2). Lanthanum hydroxide is not expected to contribute to the pseudocapacitance as it only shows a capacitance of <10 F/g. The specific capacitance is increased from 970 F/g (Ni:La = 1:0) to 1874 F/g (Ni: La = 1:2) at the discharging current of 1 A/g. At high discharging currents (e.g. 10 A/g), the Ni:La = 1:2 sample can retain a capacitance of 1055 F/g. An excellent cycling performance is demonstrated for the Ni:La = 1:2 nanocomposite sample upon 2000 cycles at the discharging current density of 2 A/g, where the stability of alpha nickel hydroxide in the alkaline solution is improved. The low temperature hydrothermal method compares favorably to other previously documented preparation processes, such as chemical coprecipitation and electrochemical deposition, for lanthanum‐doped nickel hydroxides, where the specific capacitance is typically less than 1000 F/g (1 A/g).