PANI/MWCNT电极在硫酸锂溶液中电容性能

化学氧化法制备聚苯胺/多壁碳纳米管复合材料(PANI/MWCNT),扫描电镜(SEM)、XRD及IR表征样品结构及形貌,电化学方法测定复合电极循环伏安曲线、恒流充放电曲线及电极交流阻抗.结果表明,PANI/MWCNT电极在1mol/L的Li2SO4溶液中具有较好电容性能,在电流密度为5mA/cm2时,比电容为412F/g.PANI/MWCNT电极较PANI电极有更好的大电流放电能力,50mA/cm2下复合电极的比电容仍达318F/g,为5mA/cm2时该电极比电容的77.2%,而PANI电极的比电容仅为其5mA/cm2时的56.2%.交流阻抗证明碳纳米管降低复合电极的电阻,显著提高大电流放电能力.     

电解液浓度对氢化物电极性能的影响

镍/氢化物(Ni/MH)电池以其洁净、安全、高容量、大功率、长寿命而受到人们的极大关注。贮氢电极材料的研究是开发Ni/MH电池的中心,已有较多报道。Boonstra等研究了氧化、粉末的处理等对LaNi_5电极性能的影响。本文探讨电解液浓度对MLNi_(3.5)MnCO_(0.4)Al_(0.1)(ML代表富镧混合稀土)电极放电性能的影响,并对其循环伏安性能进行了研究。 贮氢合金是在氩气保护下,将计量比的各组成元素ML、Ni、Mn、Co、Al混合物在高频感应     

铜-铈氧化还原液流电池性能

设计了一种新型Ce-Cu氧化-还原液流电池,研究了Ce³⁺/Ce⁴⁺和Cu⁰/Cu²⁺氧化还原电对的循环伏安特性,优化了电解液及电极材料,进而组装出液流电池,测试了电池的充放电性能。 结果表明,在45 mA恒电流充/放电条件下,电池放电平台电压约为1.0 V,库伦效率约100%,能量效率为75%以上,电池可稳定循环100次。     

固相合成碘酸铜及其电化学行为

用液相及固相合成方法合成了2种不同形貌的碘酸铜微粒,扫描电子显微镜(SEM)、X射线衍射(XRD)、交流阻抗、线性扫描(LSV)和恒流放电等测试技术对微粒的形貌、电化学性能及其可能的放电机理进行了表征和讨论。结果表明,用固相合成的样品具有明显的优越性,不仅放电电位增大且放电时间增长,放电容量可达891.5 mA.h/g,接近碘酸铜900 mA.h/g的理论容量。     

Li2FeSiO4/C正极材料的固相合成及电化学性能

以偏硅酸锂、草酸亚铁为原料,通过机械球磨-固相烧结法制得了Li2FeSiO4/C正极材料.用X射线衍射(XRD)和扫描电子显微镜(SEM)表征观察材料的结构和形貌.恒流充放电测试电极电化学性能.结果表明,30oC下1.5~4.8 V电位范围,于10 mA·g-1电流密度恒流充放电测试,Li2FeSiO4/C电极首次放电容量达167 mAh·g-1,有良好的电化学性能.     

采用新颖喷墨打印技术制备的薄膜LiCoO2电极及其电化学性能

采用喷墨打印技术制备了LiCoO2薄膜电极. 用X射线衍射、扫描电镜(SEM)、循环伏安和恒电流充放电试验对薄膜电极进行结构表征和电化学性能测试. SEM结果表明, 所制备的薄膜电极表面粒子分布均匀, 厚度约为1.27 μm. 经过轻微热处理(450 ℃, 30 min)的薄膜LiCoO2电极呈现出稳定的充放电循环性能. 当以20 μA/cm2进行充放电时, 第50次循环容量保持率约为首次放电容量(81 mA·h/g)的87%, 10次循环后的充放电过程的充放电效率均接近100％.     

碱性溶液中空气电极催化剂Co-N/C的研究

采用简单热处理方式制备了空气电极用氧还原电催化剂Co-N/C(800),利用线性电位扫描、控电流极化曲线及单电池测试等方法评价Co-N/C(800)的氧还原反应(ORR)催化活性。结果表明:该催化剂在碱性溶液中(1 mol/LNaOH)对ORR有很好的催化活性,起始氧还原电位约为0.04 V(vs.Hg/HgO);在室温及空气气氛条件下,以Co-N/C(800)制备的空气电极在7 mol/L NaOH溶液中时性能最佳,在电极电位为-0.6 V(vs.Hg/HgO)时电流密度达100 mA/cm2;自制的空气电极与纯锌片所组装的锌-空气电池,以7 mol/L NaOH为电解液,在电池过电位为0.8 V时,电流密度超过了100 mA/cm2,催化性能优于常规MnO2催化剂;同时进行了单电池放电测试,放电平台保持在1.25～1.30 V且性能稳定。     

碳酸铅制备铅酸蓄电池电极的研究Ⅱ.涂膏式电极的制备

由PbCO3 、添加剂和硫酸溶液分别混合成正、负极膏 ,制成涂膏式铅酸蓄电池电极 .研究了不同化成方法和充放电条件对电极放电容量和活性物质利用率的影响 .结果表明 ,正极以 2 .0mA/cm2 化成后 ,在同一电流密度下充放电时 ,其性能优于较高电流密度化成的电极 ,活性物质利用率达 74.4% ;以不对称方波电流化成的负极 ,其活性明显高于恒电流化成负极的活性 .这种电极在 2 .0mA/cm2 放电条件下 ,活性物质利用率达 90 %以上 .文中还讨论了由上述正负极组成的简单模拟电池的放电行为 .     

对甲苯磺酸掺杂聚(苯胺/中性红)复合物的乳液聚合法制备及电化学电容行为

以对甲基苯磺酸(TSA)为掺杂剂和乳化剂, 过硫酸铵(APS)为引发剂, 采用现场乳液聚合方法合成了对甲基苯磺酸掺杂聚(苯胺/中性红)复合材料(TSA-PANI/PNR). 利用X射线衍射(XRD)和电子扫描显微镜(SEM)对共聚物复合材料的结构和形貌进行了分析和表征. 以此复合材料为活性物质制备电极, 以l mol/L H₂SO₄水溶液为电解液组装超级电容器, 通过恒电流充放电、循环伏安和交流阻抗等技术研究了其电化学性能. 研究结果表明, TSA-PANI/PNR电极具有比TSA/PANI更优良的电化学性能. 扫描速度为1 mV/s的循环伏安曲线计算结果表明, 其单电极比电容可达到1350 F/g, 而TSA/PANI在相同的扫速下其单电极比电容仅为1038 F/g; 在5 mA放电电流下, TSA-PANI/PNR组装的电容器首次充放电比电容可达到348 F/g, 1000次循环后容量保持87%.     

单斜层状结构锂离子电池正极材料LiY_xMn_(1-x)O_2的合成及其电化学性能

以Na2CO3、(CH3CO2)2Mn.4H2O、Y2O3和CH3COOLi.2H2O为原料,采用高温固相法经过2次灼烧和水热离子交换法得到一系列钇掺杂的LiMn1-xYxO2(x:0.01,0.02,0.03,0.05)化合物。通过XRD、XPS、循环伏安及恒电流充放电测试技术,研究了钇掺杂离子对合成正极材料结构及电化学性能的影响。结果表明,所得产物均具有单斜层状结构。合适的钇掺杂可以起到扩展锂离子脱嵌通道和稳定骨架结构的作用,钇离子的引入部分取代原有的三价锰离子,由于钇离子的离子半径较三价锰离子大,因此稀土掺杂锰酸锂材料的晶胞参数比未掺杂材料大,在一定程度上扩充了锂离子迁移的三维通道,更有利于锂离子的嵌入与脱嵌,提高单斜层状LiMnO2材料的电化学循环可逆性及循环稳定性。通过对所得化合物进行了钇掺杂量及电化学性能的研究,得到性能比较优良的LiY0.021Mn0.979O2化合物,其首次放电比容量为125.7mA.h/g,100次循环以后,放电比容量达212.1mA.h/g,远高于未掺杂材料的放电容量138mA.h/g。交流阻抗测试结果表明,Y3+的掺入能降低材料的电化学反应阻抗和提高材料中Li+的扩散能力。     

贮氢合金表面处理改善Ni/MH电池1C充放电性能

研究了贮氨合金两种表面化学处理方法对MH电极活化性能及Ni／MH电池IC充放电性能的影响：第一种处理方法是贮氢合金在6th。l·L－’KOH溶液中80T处理sh，第二种处理方法是在含有0．04mol·L－‘KBH4的6mol·L’‘KOH溶液中80t处理sh．通过MH电极的放电容量、充放电过程中电极极化和电化学阻抗谱测试评价了上述化学处理对电极活化性能的影响．电子探针表面分析表明化学处理后贮氢合金表面由于铝元素的优先溶解形成一层具有较高电催化活性的富镍表面层，它是改善电极活化性能的主要原因·以处理的贮氨合金为负极材料的Ni／MH电池具有较高IC充放电循环寿命和1．ZV以上放电容量．     

在充放电循环过程中Ni/MH电池正负极的结构和性能变化

本文对在连续进行充放电循环过程中Ni/MH电池的放电容量、中值电压与循环周期的关系以及电池正负极结构和性能的变化进行了研究。结果表明：电池在循环过程中正极活性物质基本构型未变化，而负极储氢合金表面逐渐生成了La(OH)₃、Al(OH)₃、LiMnO₂，正负极活性物质随循环次数的增加不断发生粉化，这些都是导致Ni/MH电池放电性能下降的主要因素。     

MlNi4Al和MlNi4Mn贮氢电极性能的研究

ＭｌＮｉ４Ａｌ和ＭｌＮｉ４Ｍｎ贮氢电极性能的研究＊赵东江马松艳（绥化师专化学系绥化１５２０６１）关键词贮氢电极循环寿命自放电中图分类号Ｏ６４６．５４镍／氢化物（Ｎｉ／ＭＨ）二次电池以其洁净、安全、高容量、大功率及长寿命等特点受到极大关注。贮氢电极材料...     

Crystallographic and electrochemical characteristics of La(0.7)Mg(0.3)Ni(5.0-x)(Al(0.5)Mo(0.5)x hydrogen-storage alloys.

The structure, hydrogen-storage property and electrochemical characteristics of La(0.7)Mg(0.3)Ni(5.0-x)(Al(0.5)Mo(0.5))x (x = 0-0.8) hydrogen-storage alloys have been studied systematically. X-ray diffraction Rietveld analysis shows that all the alloys consist of an La (La,Mg)2Ni9 phase and an LaNi5 phase. The pressure-composition isotherms indicate that the hydrogen-storage capacity first increases and then decreases with increasing x, and the equilibrium pressure decreases with increasing x. Electrochemical measurements show that the maximum discharge capacity and the exchange-current density of the alloy electrodes increase as x increases from 0 to 0.6 and then decrease when x increases further from 0.6 to 0.8. Moreover, the low-temperature dischargeability of the alloy electrodes increases monotonically with increasing x in the alloys.     

Crystal structure of novel compounds in the systems Zr-Cu-Al, Mo-Pd-Al and partial phase equilibria in the Mo-Pd-Al system

The crystal structures of three Al-rich compounds have been solved from X-ray single crystal diffractometry: τ(1)-MoPd(2-x)Al(8+x) (x = 0.067); τ(7)-Zr(Cu(1-x)Al(x))(12) (x = 0.514) and τ(9)-ZrCu(1-x)Al(4) (x = 0.144). τ(1)-MoPd(2-x)Al(8+x) adopts a unique structure type (space group Pbcm; lattice parameters a = 0.78153(2), b = 1.02643(3) and c = 0.86098(2) nm), which can be conceived as a superstructure of the Mo(Cu(x)Al(1-x))(6)Al(4) type. Whereas Mo-atoms occupy the 4d site, Pd(2) occupies the 4c site, Al and Pd(1) atoms randomly share the 4d position and the rest of the positions are fully occupied by Al. A B?rnighausen tree documents the crystallographic group-subgroup relation between the structure types of Mo(Cu(x)Al(1-x))(6)Al(4) and τ(1). τ(7)-Zr(Cu(1-x)Al(x))(12) (x = 0.514) has been confirmed to crystallize with the ThMn(12) type (space group I4/mmm; lattice parameters a = 0.85243(2) and c = 0.50862(3) nm). In total, 4 crystallographic sites were defined, out of which, Zr occupies site 2a, the 8f site is fully occupied by Cu, the 8i site is entirely occupied by Al, but the 8j site turned out to comprise a random mixture of Cu and Al atoms. The compound τ(9)-ZrCu(1-x)Al(4) (x = 0.144) crystallizes in a unique structure type (space group P4/nmm; lattice parameters a = 0.40275(3) and c = 1.17688(4) nm) which exhibits full atom order but a vacancy (14.4%) on the 2c site, shared with Cu atoms. τ(9)-ZrCu(1-x)Al(4) is a superstructure of Cu with an arrangement of three unit cells of Cu in the direction of the c-axis. A B?rnighausen tree documents this relationship. The ZrCu(1-x)Al(4) type (n = 3) is part of a series of structures which follow this building principle: Cu (n = 1), TiAl(3) (n = 2), τ(5)-TiNi(2-x)Al(5) (n = 4), HfGa(2) (n = 6) and Cu(3)Pd (n = 7). A partial isothermal section for the Al-rich part of the Mo-Pd-Al system at 860 °C has been established with two ternary compounds τ(1)-MoPd(2-x)Al(8+x) and τ(2) (unknown structure). The Vickers hardness (H(v)) for τ(1) was found to be 842 ± 40 MPa.     

Cubic aluminum silicides RE8Ru12Al49Si9(Al(x)Si12-x) (RE = Pr, Sm) from liquid aluminum. Empty (Si,Al)12 cuboctahedral clusters and assignment of the Al/Si distribution with neutron diffraction.

Two new quaternary aluminum silicides, RE8Ru12Al49Si9(Al(x)Si12-x) (x approximately 4; RE = Pr, Sm), have been synthesized from Sm (or Sm2O3), Pr, Ru, and Si in molten aluminum between 800 and 1000 degrees C in sealed fused silica tubes. Both compounds form black shiny crystals that are stable in air and NaOH. The Nd analog is also stable. The compounds crystallize in a new structural type. The structure, determined by single-crystal X-ray diffraction, is cubic, space group Pm3m with Z = 1, and has lattice parameters of a = 11.510(1) A for Sm8Ru12Al49Si9(Al(x)Si12-x) and a = 11.553(2) A for Pr8Ru12Al49Si9(Al(x)Si12-x) (x approximately 4). The structure consists of octahedral units of AlSi6, at the cell center, Si2Ru4Al8 clusters, at each face center, SiAl8 cubes, at the middle of the cell edges, and unique (Al,Si)12 cuboctohedral clusters, at the cell corners. These different structural units are connected to each other either by shared atoms, Al-Al bonds, or Al-Ru bonds. The rare earth metal atoms fill the space between various structural units. The Al/Si distribution was verified by single-crystal neutron diffraction studies conducted on Pr8Ru12Al49Si9(Al(x)Si12-x). Sm8Ru12Al49Si9(Al(x)Si12-x) and Pr8Ru12Al49Si9(Al(x)Si12-x) show ferromagnetic ordering at Tc approximately 10 and approximately 20 K, respectively. A charge of 3+ can be assigned to the rare earth atoms while the Ru atoms are diamagnetic.     

Self-discharge behavior of LaNi5-based hydrogen storage electrodes in different electrolytes

Nickel–metal hydride (Ni–MH) batteries using hydrogen storage alloys as negative electrode materials have been developed and commercialized because of their high energy density, high rate capability and long cycle life, without causing environmental pollution (Song et al. J Alloys Comp 298:254, 2000; Jang et al. J Alloys Comp 268:290, 1998). However, the self-discharge rate is relatively higher than that of the Ni–Cd batteries, which would certainly be disadvantageous in practical applications. The capacity loss of a battery during storage is often related to self-discharge in the cells. Self-discharge takes place from a highly charged state of a cell to a lower state of charge (SOC) and is typically caused by the highly oxidizing or reducing characteristic of one or both of the electrodes in the cell. This self-discharge behavior may be affected by various factors such as gases, impurities, temperature, type of alloy electrode, electrolytes, or charge/discharge methods. The loss of capacity can be permanent or recoverable, depending on the nature of the mechanism (chemical or electrochemical) and aging condition. In this paper, the effects of electrolyte composition and temperature on self-discharge behavior of LaNi₅-based hydrogen storage alloy electrodes for Ni–MH batteries have been investigated. It was found that both reversible and irreversible capacity loss of MH electrode tested at 333 K were higher than that at 298 K. When tested at 298 K and 333 K, reversible capacity loss was mainly affected by the electrolyte, while the irreversible capacity loss was not affected. The dissolution of Al from the electrode can be reduced more effectively in an electrolyte with Al addition, compared with that in normal electrolyte. This resulted in a lower reversible capacity loss for the electrode exposed in the Al³⁺-rich electrolyte. SEM analysis has shown that some needle shape and hexagonal corrosion products were formed on the surface of the alloy electrodes, especially after storage at high temperature.     

氢化物电极中Mn的偏析

镍/氢化物(Ni/MH)电池具有高能量、无电解液浓缩、耐过充放、无毒、不使用贵金属等特点。70年代起已开始这方面的研究,近年来尤其活跃。美国、日本等已试制了性能较好的此类电池。我国南开大学、机电部十八所、浙江大学等也已开展了研究。     

MH/Ni电池用稀土系储氢合金的失效及回收研究

探讨了深度过放电对MH／Ni电池负极储氢合金的影响。发现在过放电后，负极储氢合金的XRD结构图中，除了储氢合金的主相外，还出现了十分明显的Al(OH3),La(OH)3的衍射峰。结合各种情况下储氢合金失效的,原因利用化学处理及再熔炼的方法对失效MH／Ni电池的负极粉进行了回收实验，并对比了回收合金与原合金的结构及电化学性能。XRD测试结果表明回收合金与原合金的结构相同，均为CaCu5型。恒电流充放电实验发现，回收合金与原合金粉相比，放电容量接近，放电电位高。不寿命测试结果表明，回收合金较原合金容量衰减更缓慢。