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1.
杨泰    张羊换    陈莉翠    王海涛    任慧平  赵栋梁 《功能材料》2013,(19)
采 用 真 空 感 应 熔 炼 制 备 了La0.8Mg0.2Ni3.3Co0.2Six(x=0、0.1)电极合金,并将铸态合金进行真空退火处理,退火温度为900、950、1000和1050℃,保温时间为8h。用XRD分析了铸态及退火态合金的相结构,测试了铸态及退火态合金的电化学贮氢性能。结果表明,铸态及退火态合金均具有多相结构,包括两个主相(La,Mg)2Ni7和LaNi5以及一个残余相LaNi3。退火处理未改变合金的相组成,但使两个主相的含量发生明显改变。合金主相的晶格常数及晶胞体积随退火温度的增加而增加。铸态及退火态合金均具有良好的活化性能,第1次循环即可达到最大放电容量。退火处理明显改善了合金的电化学循环稳定性,合金的放电容量随退火温度的升高先增加后减小。合金的高倍率放电性能(HRD)、电化学交流阻抗谱(EIS)以及氢扩散系数(D)的测试表明,合金的电化学动力学随退火温度的升高先上升后降低。  相似文献   

2.
采用真空感应熔炼制备了La0.8Mg0.2Ni3.3Co0.2Si x(x=0、0.1)电极合金,并将铸态合金进行真空退火处理,退火温度为900、950、1000和1050℃,保温时间为8h。用XRD分析了铸态及退火态合金的相结构,测试了铸态及退火态合金的电化学贮氢性能。结果表明,铸态及退火态合金均具有多相结构,包括两个主相(La,Mg)2Ni7和LaNi5以及一个残余相LaNi3。退火处理未改变合金的相组成,但使两个主相的含量发生明显改变。合金主相的晶格常数及晶胞体积随退火温度的增加而增加。铸态及退火态合金均具有良好的活化性能,第1次循环即可达到最大放电容量。退火处理明显改善了合金的电化学循环稳定性,合金的放电容量随退火温度的升高先增加后减小。合金的高倍率放电性能(HRD)、电化学交流阻抗谱(EIS)以及氢扩散系数(D)的测试表明,合金的电化学动力学随退火温度的升高先上升后降低。  相似文献   

3.
邓安强  罗永春  王浩  赵磊  罗元魁 《材料导报》2018,32(15):2565-2570
利用高频感应熔炼法制备La0.63(Pr0.1Nd0.1Y0.6Sm0.1Gd0.1)0.2Mg0.17Ni3.1Co0.3Al0.1储氢合金,对铸态合金在900℃下退火热处理24h。结构分析表明,铸态合金微观组织由CaCu5型结构、Ce5Co19型结构及Ce2Ni7型结构三相组成,而退火合金则是单相Ce2Ni7型结构。铸态和退火合金电极均具有良好的活化性能,退火合金电极放电曲线更为平坦和宽阔。两种合金电极腐蚀电位基本一致,但铸态合金电极腐蚀电流更大。合金经过退火后其电极循环稳定性(S100=83.5%)明显优于铸态合金电极(S100=69%)。在100次电化学充放电循环内,低容量充电时,退火合金电极容量不衰减,合金电极容量衰减的充电容量临界点为活化最大放电容量(Cmax)的90%。铸态和退火合金电极动力学性能差别不大,铸态合金电极高倍率放电主要由氢在其体相中扩散控制,退火合金电极高倍率放电则主要由其表面电荷转移控制。  相似文献   

4.
采用真空电弧炉(在氩气保护下)制备Zr1-xTixMn0.4Cr0.4Ni1.2贮氢合金,通过XRD、SEM和恒流充放电研究了合金的相结构、形貌和电化学性能。结果表明:Ti为C14型Laves相的稳定性元素,随着Ti含量的增加,C14型Laves相增多,C15型Laves相减少。当x=0.1时,合金综合性能最好,表现出良好的活化性能、循环稳定性能和高倍率放电特性,在放电电流300mA/g的条件下,充放电循环50次,合金保持稳定的放电容量。当X〉0.1时,合金放电容量下降。Ti的加入使合金氢化物稳定性降低,加入少量Ti,有利于合金的放电容量的提高和高倍率放电性能的提高。  相似文献   

5.
系统研究了LaMgNi3.7M0.3(M=Ni、Al、Mn、Co、Sn、Cu)合金的组织结构和电化学性能。XRD和电子探针显微分析(EPMA)结果表明:该系列合金主相均为LaMgNi4相,其中含Mn、Cu和Co元素在LaMgNia合金相中有一定的固溶度,LaMgNi3.7Sn0.3合金中的Sn元素主要以LaNiSn相析出;XRD全谱拟合分析表明:LaMgNi3.7Al0.3中Al元素主要占据在LaNi5相的3g位置。合会化元素在LaMgNi4相中的固溶度从大到小的顺序是Mn〉Cu〉Co〉Al〉Sn。电化学实验表明,该系列合金经1~3次循环即可活化,最大放电容量由245.2mAh/g(M=Sn)变化至293.2mAh/g(M=Co),但合金电极的循环稳定性均较差。合金电极的高倍率放电性能(HRD900%)从大到小依次为Al〉Sn〉Cu〉Mn〉Ni〉Co,其中氢原子在合金中的扩散时合金电极的高倍率放电性能起主要作用。  相似文献   

6.
研究了铸态及退火(940℃、8h)La0.75Mg0.25Ni3.5Si0.10储氢合金相结构,及在30、45、55和70℃环境温度下电化学性能,包括放电容量、寿命、高倍率和自放电行为。X射线衍射分析表明,两合金均为La-Ni5、(La,Mg)2Ni7和(La,Mg)Ni3相组成的多相结构,退火处理使LaNi5和(La,Mg)Ni3相减少,(La,Mg)2Ni7相增多,但两合金主相均为LaNi5。研究发现,铸态和退火态合金活化性能都较优异,最大放电容量均随测试温度升高而减小,并且退火处理能提高每个温度点的放电容量,70℃高温下最为显著,合金放电容量从238.4mAh/g增加到342.5mAh/g。随温度升高,铸态合金的高倍率放电性先增大后减小,而退火合金高倍率放电性随温度升高单调增加。合金的荷电保持率随温度升高而降低,退火处理可提高各个温度点的荷电保持率。  相似文献   

7.
系统研究了单辊快淬快速凝固处理对低Co贮氢合金MlNi4.0Co0.2Mn0.40Al0.30Cu0.10的相结构和电化学性能的影响.XRD分析表明,铸态和快凝合金均为单相CaCu5型结构,但快凝合金的成分和结构均匀性得到明显改善,并具有较低的吸氢体积膨胀率(△V/V).电化学测试表明,快速凝固处理后合金的活化性能不变,循环稳定性得到显著改善,但其放电容量和高倍率放电性能有所降低.研究发现,快速凝固低Co合金循环稳定性能的改善主要归结于快凝合金具有较低的吸氢体积膨胀率和较好的成分均匀性,而快凝合金电极的电催化活性以及氢在合金中的扩散速率较铸态合金有所减小是导致其高倍率放电性能降低的主要原因.  相似文献   

8.
张羊换  王国清  董小平  任江远  郭世海  王新林 《功能材料》2005,36(9):1363-1367,1371
用铸造及快淬工艺制备了AB5型Mm(NiMnSiAl)4.3Co0.6-xFex(x=0、0.1、0.2、0.3、0.4、0.5、0.6)贮氢合金,用XRD、TEM及SEM测试了铸态及快淬态合金的微观结构,并全面测试了合金在铸态及快淬态下的电化学性能。研究了Fe替代Co对铸态及快淬态贮氢合金微观结构及电化学性能的影响。结果表明,Fe替代Co对铸态及快淬态合金的相结构没有明显影响,但对合金的电化学性能影响显著。对铸态及快淬态合金,随Fe替代量的增加舍金的容量下降,但循环寿命得到不同程度的改善。尤其使快淬态合金的循环寿命显著增加。Fe替代Co对舍金的初始活化性能没有明显影响,铸态及快淬态舍金经过2~4次循环均可完全活化。  相似文献   

9.
李嵩  季世军  孙俊才 《功能材料》2004,35(3):308-311
研究了贮氢电极合金Zr1-xTixMin0.7V0.2Co0.1Ni1.2的相结构和电化学性能。结果表明,随着掺Ti量的增加,该合金主相中C15型Laves相含量逐渐减少而C14型Laves相含量逐渐增加,同时非Laves相Zr7M10和TiNi相全部消失,说明元素Ti掺杂量的增加抑制了第二相的产生。当含Ti量x=0.2时,该合金具有最大放电容量Cmax为354mAh/g,在放电电流为300mAh/g条件下,高倍率放电性能比母体合金提高了15%。而对于合金Zr0.75Ti0.2La0.05Mn0.7V0.2Co0.1Ni1.2,其活化性能被大大提高,只需4次就能达到最大放电容量372mAh/g,而且经过30次循环仍能保持最大放电容量的93%。  相似文献   

10.
郭兴波  罗永春  高志杰  张国庆  康龙 《功能材料》2012,43(18):2450-2455
用高频感应熔炼法制备了稀土系La0.8-xGd0.2MgxNi3.3Co0.3Al0.1(x=0~0.4)储氢合金,并在氩气和1273K下对铸态合金进行退火处理,系统研究了用Mg部分替代La元素对合金微观组织和电化学性能的影响规律。合金相结构分析表明,合金组织主要由Pr5Co19型、PuNi3型、Ce2Ni7型和Ca-Cu5型相组成,随Mg含量增加,主相Pr5Co19型相含量先增加后减少,当x=0.15时达到最大值88.23%(质量分数)。电化学测试分析表明,随Mg含量的变化,合金电极最大放电容量和容量保持率均呈先增加后减小的规律,当x=0.15时,合金电极放电容量达到最大值377.9mAh/g,经100次充放电循环后其电极容量的保持率S100为90.2%,具有较好的电化学综合性能。  相似文献   

11.
LiCo0.4Ni0.3Mn0.3O2 layered oxide in a member of the LiCo1?2xNixMnxO2 solid solution between LiCoO2 and LiNi0.5Mn0.5O2. Compositions from this solid solution have attracted much attention and have been extensively studied as promising cathode candidates to replace the most popular LiCoO2 cathode material used in the commercial lithium-ion batteries (LiBs). LiCo0.4Ni0.3Mn0.3O2 positive electrode material was prepared via the combustion method followed by a thermal treatment at 900 °C for 12 h. This material was characterized by a high homogeneity and a granular shape. The Rietveld refinement evidenced that the structure of this compound exhibits no Ni/Li disorder revealing that the LiCo1?2xNixMnxO2 system presents the ideal structure for LiBs application when x < 0.4. The electrochemical performances of the LiCo0.4Ni0.3Mn0.3O2 sample were measured at different current rates in the 2.7–4.5 V potential range. Its discharge capacity reached 178, 161 and 145 mAhg?1 at C/20, 1C and 2C, respectively. Structural changes in LiCo0.4Ni0.3Mn0.3O2 upon delithiation were studied using ex situ X-ray diffraction. A continuous solid solution with a rhombohedral symmetry was detected in the whole composition range. This structural stability during the cycling combined with the obtained electrochemical features make this material convenient for the LiBs applications.  相似文献   

12.
This research article focused on developing Al0.3CrFeNiCo0.3Si0.4 nanocrystalline high-entropy alloy (HEA) by mechanical alloying. The initial powders mixture was ball milled for 1 hr (HEA-1 h), 5 hr (HEA-5 h), 15 hr (HEA-15 h) and 25 hr (HEA-25 h) at ball to powder mass ratio (BPR) of 15:1 and a speed of 300 rpm. The mechanical alloying time was varied from 1 to 25 hr to ensure the nanocrystalline nature and attainment of steady state in HEA powders. The structure of the developed HEAs was characterized by means of X-ray diffraction (XRD), Laser particle size analyzer (LPSA), and various electron microscopes (TEM and FEGSEM with EDS). HEA-25hr sample exhibited the crystallite size of 13.8 nm with lattice strain of 0.67% obtained from XRD which matched the result by TEM. The formation of a solid solution (SS) with a uniform elemental dispersion was observed with a major BCC stable structure and a minor FCC structure in HEA-25 h sample. The HEA-25 h sample revealed an average particle size of 386.2 nm (89.8% peak intensity) with Polydispersity Index (PDI) value of 0.364 which confirmed the uniform distribution of particles over a narrow range of particle size. The synthesized powders were consolidated to green compacts with a loading rate of 1 mm/min at different compaction pressures (25, 50, 75, 100, 150, 200, 400, 600, 800, 1000, and 1100 MPa) for examining the powder particles packing. Several compaction models (both linear and non-linear) were discussed to establish the density-pressure relationship of developed HEAs. The results revealed that the milling time has influenced the relative density. HEA-1 h sample was exhibited the relative density of 0.76 whereas HEA-25 h sample was produced the relative density of 0.6 indicating more strength and more amount of strain hardening occurs in MAed HEA-25 sample in addition to the entropy effect for the same composition.  相似文献   

13.
Journal of Superconductivity and Novel Magnetism - Magnetic phase coexistence in the substituted perovskite compound, La0.4Bi0.3Sr0.3MnO3, is attributed to the spontaneous moment and a step-like...  相似文献   

14.
采用高温固相法合成了Sn4+、Sm3+双掺杂的BaCeO3-BaZrO3固溶体——BaCe0.4Zr0.3Sn0.1Sm0.2O3-α(BCZSS)固体电解质材料,并进行了XRD、SEM测试表征。采用同位素效应、浓差电池等电化学方法研究了样品在873~1073K的离子导电特性。浓差电池测试结果表明样品在湿润氧气气氛中是离子(质子+氧离子)和空穴的混合导体,样品在湿润氢气气氛下存在氧离子导电性。H2O-Ar气氛下的电导率高于相同温度下D2O-Ar气氛下的电导率,表明该样品在含水气氛中是一种优良的质子导体。  相似文献   

15.
对商用MmMn0.4Co0.7Al0.3Ni3.4贮氢合金中添加多壁碳纳米管(CNTs)、Ni的电化学性能进行了研究,结果表明,CNTs的加入可以提高电极的放电容量和初始活化性能,合金中添加CNTs、CNTs+Ni的电极完全活化只需11个循环,其最大放电容量分别为255、271mAh/g.而添加Ni的电极则需24个循环才达到最大容量(245mAh/g);合金中添加CNTs、CNTs+Ni的电极具有更高的放电平台和更好的高倍率放电性能(HRD),在1000mAh/g放电电流下,添加CNTs、CNTs+Ni、Ni以及未添加电极的HRD值依次为80.5%、83.9%、66.9%和62.4%,线性极化和电化学阻抗测试表明,CNTs的加入可有效减少欧姆电阻、提高电极表面的电荷迁移速率,更有利于在大电流下进行放电。  相似文献   

16.
通过水冷和空冷两种冷却方式制备成分相同的Mg-4.4Zn-0.3Zr-0.4Y(质量分数/%,下同)铸态合金,挤压变形后进行时效处理,研究不同熔体冷却速率对挤压态和时效态合金组织性能的影响。结果表明:通过水冷冷却可以显著细化铸态组织,促进I相(Mg3YZn6)的生成,并抑制W相(Mg3Y2Zn3)的形核;由于初始组织不同,水冷和空冷两种冷却方式铸造的Mg-4.4Zn-0.3Zr-0.4Y合金经过挤压变形后,抗拉强度分别达到327MPa和306MPa,伸长率分别达到14.8%和10.0%;时效处理后,合金的晶粒尺寸和织构强度变化很小,析出的MgZn相和MgZn2相含量成为影响时效态合金性能的主要因素;时效处理挤压态水冷冷却铸造合金的屈服强度和抗拉强度分别达到330MPa和348MPa,伸长率为14.4%,与时效前相比略有减小;时效处理挤压态空冷铸造合金的屈服强度和抗拉强度增大至344MPa和359MPa,伸长率降至8.6%。  相似文献   

17.
In the present work, the structure of As0.3Seo.3S0.4Ge0.1 chalcogenide glass has been studied using the radial distribution function (RDF). Moreover, the effect of annealing temperature on the short range order of this glass has been investigated. The results revealed that the short range order structure of the as-prepared and annealed As0.3Se0.2S0.4Ge0.1 chalcogenide glass is close to a regular tetrahedron. The medium range order of As0.3Se0.4S0.4Ge0.1 chalcogenide glass is topology order. The topological structure of the medium range order can be described by the Phillips model. The structure of As0.3Se0.2S0.4Ge0.1 chalcogenide glass is stable in the annealing temperature range 324–523 K.  相似文献   

18.
We investigated the formation of W2B5 and β-WB precipitates in supersaturated Ti0.3W0.4Cr0.3B2 solid solutions during isothermal annealing at temperatures between 1400 and 1600 °C. X-ray diffractometry measurements showed that the precipitation process is very complex including metastable phase formation and mutual transformation between the two precipitation phases. The rate constants of precipitation are determined as a function of reciprocal temperature and discussed in framework to literature data.  相似文献   

19.
Nanocomposite based cathode materials compatible for low temperature solid oxide fuel cells (LTSOFCs) are being developed. In pursuit of compatible cathode, this research aims to synthesis and investigation nanocomposite La0.3Sr0.2Mn0.1Zn0.4 oxide-Sm0.2Ce0.8O1.9 (LSMZ-SDC) based system. The material was synthesized through wet chemical method and investigated for oxide-ceria composite based electrolyte LTSOFCs. Electrical property was studied by AC electrochemical impedance spectroscopy (EIS). The microstructure, thermal properties, and elemental analysis of the samples were characterized by TGA/DSC, XRD, SEM, respectively. The AC conductivity of cathode was obtained for 2.4 Scm(-1) at 550 degrees C in air. This cathode is compatible with ceria-based composite electrolytes and has improved the stability of the material in SOFC cathode environment.  相似文献   

20.
用共沉淀法合成了用铝掺杂的铁部分取代锰的富锂正极材料Li[Li0.2Mn0.4Fe0.3Al0.1]O2。采用XRD、SEM、电化学测试等方法对样品进行表征。结果表明,与Li[Li0.2Mn0.45Fe0.35]O2相比,Li[Li0.2Mn0.4Fe0.3Al0.1]O2具有较好的电化学性能,其初始容量达到241mAh/g左右,经50次充放电循环后,容量衰减率在7%左右。  相似文献   

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