熔盐电脱氧法制备锂离子电池负极材料Ni3Sn2合金的研究

以烧结的SnO2-NiO片体为阴极,高密度石墨碳棒为阳极,在850℃的CaCl2熔盐中进行电脱氧反应,制得了Ni3Sn2合金.研究了电解电压、电解时间对电解过程的影响.采用电子扫描显微镜(SEM)分析了样品电解前后的微观形貌;采用X射线衍射仪(XRD)分析了电解产物的相组成.结果表明,当电解电压在2.8～3.2V之间时,可制备出纯相的Ni3Sn2合金粉末,且电解电压越高,电脱氧反应速率越快.电脱氧过程是从外向里分步进行的.     

无钕稀土系贮氢合金及其在动力电池中的应用

研究了薄壁铸造的无钕稀土LPC系贮氢合金,发现铸态高钴合金的综合电化学性能随着铸锭厚度的增加而改善,原因为晶胞体积增加、晶界缺陷减少和晶格应力降低;铸态低钴合金的电化学性能对厚度不敏感,归因于合金中Cu、Fe和Si等元素的引入.退火能够提高高钴合金的放电容量,并改善其循环稳定性,壁厚最薄的3mm合金显示出最好的综合电化学性能,主要应归功于晶格应力的降低,和元素偏析的改善.Ce/TE为20%～25%时,高钴合金可以得到最好的综合电化学性能.成分和工艺优化后的贮氢合金应用在Ni/MH电池和电动自行车中,得到了令人满意的结果.     

SnO2/高岭土复合材料作为锂离子负极材料的研究

以氯化亚锡和高岭土为原料,通过醇解,氨解反应,制备了纳米SnO2/高岭土复合材料.利用XRD、TEM测试技术对复合材料进行了表征.结果表明,550℃焙烧后复合材料中的SnO2粒子平均粒径在20nm左右,较纯材料中的SnO2粒子团聚现象减少.将复合材料作为锂离子负极材料进行了研究,与纯氧化锡相比这种复合材料具有较高可逆容量(达741mAh/g),同时循环性能也得到了提高.     

On the elemental substitutions of titanium-based hydrogen-storage alloy electrodes for rechargeable Ni–MH batteries

Partial substitutions of nickel in Ti2Ni intermetallic compound with cobalt, potassium, boron and aluminium have been studied in the present paper. It is found that cobalt and boron additions are beneficial but aluminium addition is detrimental to the specific capacity of the electrode. Potassium does not have any significant effect on the specific capacity of the electrode from our work. Cobalt, potassium and aluminium additions are all found effective in increasing the cycle life of Ti2Ni electrode, although by different mechanisms. This revised version was published online in November 2006 with corrections to the Cover Date.     

Preparation and electrochemical properties of nano-sized SnF2 as negative electrode for lithium-ion batteries

Nanocrystalline SnF₂ was prepared via recrystallization of commercially available tin (II) fluoride. The electrochemical performance of tin fluoride as anode material for Li-ion batteries was investigated. The cyclic voltammetry of the obtained material showed occurrence of SnF₂ decomposition at first and a typical reversible alloying/de-alloying process at low potentials. Furthermore, it was found that the synthesized material delivered a high reversible capacity of 1016 mAh g^− 1 and a capacity retention of 54.8% after 30 cycles when the electrode was cycled at a current of 100 mA g^− 1.     

镍氢电池掺钴镍正极的研究进展

对镍氢电池的镍正极覆钴改性的研究进展进行了综述,系统归纳了添加剂Co、CoO、Co(OH)2、CoOOH对电池镍正极性能的改善及覆钴工艺的研究进展,并对覆钴工艺的前景提出了新的展望.     

MH/Ni电池负极材料储氢合金表面修饰及性能研究

探索了一种储氢合金表面修饰的新方法,应用HF和CuSO4混合溶液对MH/Ni电池负极AB5型储氢合金进行表面处理.研究了HF含量对合金表面修饰的影响,考察了修饰后合金电极的电化学性能,应用交流阻抗分析了表面处理对合金性能影响的作用机理.结果表明,表面修饰使合金表面活性增加,导电性增强,使合金电极具有更好的活化速度和高倍率放电能力.另外,表面修饰还抑制了合金的粉化、氧化,改善了合金电极的循环性能.因此,表面修饰合金作为MH/Ni电池负极材料可以更好的满足电动车用动力型电源的性能要求.     

Mn,N co-doped Co nanoparticles/porous carbon as air cathode for highly efficient rechargeable Zn-air batteries

Oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)are generally catalyzed by precious metals(Pt)and metal oxides(IrO2)which still have many shorta...     

锂离子电池用Sn-MCMB复合材料碳热还原合成的研究

用碳热还原法制备了Sn-MCMB复合材料，通过XRD、SEM、恒流充放电循环和慢速扫描循环伏安（CV）等方法对其电化学嵌脱锂性能做了研究。结果表明：SnO2被MCMB还原成金属Sn圆球颗粒，吸附在McMB上的球径平均尺寸为500nm，而未吸附的为15μm，均匀分散在MCMB微球之间。该材料的首次嵌脱锂比容量分别可以达到892和657mAh／g，库仑效率为73％，循环14周以后的脱锂比容量为366mAh／g。     

Ni2V2O7 thin films for negative electrode application of rechargeable microbatteries

Metallic thin films Ni/V/(Ni/V)_x/Ni were deposited under vacuum with an electron beam on Pt sheet substrates. The thickness of the films was measured in situ by the vibrating quartz method in order to achieve the atomic ratio Ni/V=1. Samples were first annealed for 30 min under vacuum at 853 K in order to initiate the metals interdiffusion and annealed for another 30 min in room atmosphere at 863 K. The films were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). Results show that monoclinic homogeneous Ni₂V₂O₇ thin films can be synthesized on Pt substrates by this simple technique. These Ni₂V₂O₇ were tested for their Li insertion properties in standard laboratory Li batteries. It is shown that the cycling behavior of the films is much more favorable than that of the bulk powders. The hypothesis that this behavior is linked to improved grain size and film morphology is discussed     

Influence of solvents on the synthesis and electrochemical properties of Li[Li1/5Ni1/10Co1/5Mn1/2]O2 for the applications in lithium-ion batteries

The solid solution of Li[Li_1/5Ni_1/10Co_1/5Mn_1/2]O₂ was synthesized using starting materials with two different functional groups (hydroxide and acetate) in the presence of a reaction medium ethanol or acetone using solid-state reaction method. The prepared samples were found to posses layered structure and their electrochemical properties were greatly influenced by the functional group of the starting materials. The samples which were prepared with same functional group offered better electrochemical properties and addition of solvents during the ball milling of the samples has considerably enhanced the diffusivity of the chemical species in the layered compound. The electrochemical properties and the influence of starting materials on the added solvents are discussed.     

Ni(OH)2 Nanoflakes Supported on 3D Ni3Se2 Nanowire Array as Highly Efficient Electrodes for Asymmetric Supercapacitor and Ni/MH Battery

Porous Ni(OH)₂ nanoflakes are directly grown on the surface of nickel foam supported Ni₃Se₂ nanowire arrays using an in situ growth procedure to form 3D Ni₃Se₂@Ni(OH)₂ hybrid material. Owing to good conductivity of Ni₃Se₂, high specific capacitance of Ni(OH)₂ and its unique architecture, the obtained Ni₃Se₂@Ni(OH)₂ exhibits a high specific capacitance of 1689 µAh cm^?2 (281.5 mAh g^?1) at a discharge current of 3 mA cm^?2 and a superior rate capability. Both the high energy density of 59.47 Wh kg^?1 at a power density of 100.54 W kg^?1 and remarkable cycling stability with only a 16.4% capacity loss after 10 000 cycles are demonstrated in an asymmetric supercapacitor cell comprising Ni₃Se₂@Ni(OH)₂ as a positive electrode and activated carbon as a negative electrode. Furthermore, the cell achieved a high energy density of 50.9 Wh L^?1 at a power density of 83.62 W L^?1 in combination with an extraordinary coulombic efficiency of 97% and an energy efficiency of 88.36% at 5 mA cm^?2 when activated carbon is replaced by metal hydride from a commercial NiMH battery. Excellent electrochemical performance indicates that Ni₃Se₂@Ni(OH)₂ composite can become a promising electrode material for energy storage applications.     

Synthesis,structural characterization and hydrogenation behaviour of the new hydrogen storage composite alloy La2Mg17-x wt% LaNi5

Alloys with the general formula La₂Mg₁₇-xwt % LaNi₅ (x=10, 20, 30 and 40) have been synthesized and the hydrogen storage capacity of these new composite materials investigated. The materials were activated at temperatures of 360 °C under a hydrogen pressure of 33 kg cm^–2. Optimum storage capacity of 5.24% in terms of pressure and composition was observed for La₂Mg₁₇-10 wt% LaNi₅ at 400°C. This is one of the very highest hydrogen storage capacities known so far. The hydriding rate of La₂Mg₁₇ in the presence of LaNi₅ is about 3–4 times that of La₂Mg₁₇ alone. In order to elucidate the role of LaNi₅ in accelerating the hydrogen desorption rate of La₂Mg₁₇, the structural and microstructural characteristics of the composite material were carried out employing the XRD, SEM and EDAX techniques. The hydriding rate and hydrogen storage capacity are closely related to the microstructure and the types of phase present in the alloys.     

Sintering behaviour of Ti-2Ni and Ti-5Ni elemental powders

The effect of nickel powder additions (2 and 5 at.%) on the sintering behaviour of titanium powder has been investigated through the dilatometric sintering study. The sintering of titanium powder was found to be enhanced significantly and the activation energies were decreased with increasing nickel content. The sintering of Ti-2 at.% Ni system at lower temperature was found to be controlled by Ti-Ti and Ti-Ni solid state sintering, whereas inter-diffusion dominates in Ti-5 at.% Ni sintering. At higher temperatures, sintering was found to be controlled by mixed mechanisms, i.e. inter-diffusion, chemical reaction and transient liquid phase formation.     

高功率型和低温型镍氢电池用掺硼贮氢合金的研究

Ni/MH电池负极的高倍率性能和低温放电性能的提高应当受到重视，采用廉价的硼镍合金（B-Ni)作为掺硼添加剂，有效地改善常用MlNi3.55Co0.75Mn0.4Al0.3贮氢合金的高倍率性能和低温放电性能，实验结果表明，掺硼合金由于形成含CeCo4B相的复相结构可显著提高合金的电化学动力学性能，掺硼的MlNi3.55Co0.75Mn0.4Al0.3B0.3合金能够满足高功率型Ni/NH电池的高倍率性能和低温型Ni/MH电池在低温-35℃下的小倍率放电（≤120mA/g)的要求。     

锂离子电池中电解液与石墨类负极活性材料的相容性

选择了一种具有良好贮锂结构的人造石墨试样作为锂离子电池负极活性材料，考察了它在六种不同电解液中的恒电流充、放电性能和循环伏安特性，采用傅立叶变换红外光谱分析了不同电解液在试样颗粒表面发生还原反应时所形成的固体电解质中间相膜的成份和含量。据此得出的结论是：电解液与石墨类负极活性材料能否相容的问题，实质上就是所选定的电解液能否与其颗粒表面发生缓和的还原反应、生成薄而致密的只允许锂离子通过的固体电解质中间相膜。     

Spin-coated silicon nanoparticle/graphene electrode as a binder-free anode for high-performance lithium-ion batteries

Si has been considered as a promising anode material but its practical application has been severely hindered due to poor cyclability caused by the large volume change during charge/discharge. A new and effective protocol has been developed to construct Si nanoparticle/graphene electrodes with a favorable structure to alleviate this problem. Starting from a stable suspension of Si nanoparticles and graphene oxide in ethanol, spin-coating can be used as a facile method to cast a spin-coated Si nanoparticle/graphene (SC-Si/G) film, in which graphene can act as both an efficient electronic conductor and effective binder with no need for other binders such as polyvinylidenefluoride (PVDF) or polytetrafluoroethylene (PTFE). The prepared SC-Si/G electrode can achieve a high-performance as an anode for lithium-ion batteries benefiting from the following advantages: i) the graphene enhances the electronic conductivity of Si nanoparticles and the void spaces between Si nanoparticles facilitate the lithium ion diffusion, ii) the flexible graphene and the void spaces can effectively cushion the volume expansion of Si nanoparticles. As a result, the binder-free electrode shows a high capacity of 1611 mA·h·g^?1 at 1 A·g^?1 after 200 cycles, a superior rate capability of 648 mA·h·g^?1 at 10 A·g^?1, and an excellent cycle life of 200 cycles with 74% capacity retention.      

Facile synthesis Mn/Co dual-doped Ni3S2 nanosheets for supercapacitor

Journal of Materials Science: Materials in Electronics - Ni3S2 nanosheets dual-doped with manganese, cobalt elements on conductive nickel foam (MC-Ni3S2) had been synthesized by two steps...     

Li2ZrO3包覆锂离子电池正极材料Li[Li0.2Ni0.2Mn0.6]O2的制备及其电化学性能

富锂锰基材料因其具有较高的充放电比容量而备受关注。针对其首次库仑效率低、循环和倍率性能差的问题,将具有三维Li^+通道的锂离子导体Li2ZrO3引入至富锂锰基正极材料Li[Li0.2Ni0.2Mn0.6]O2的表面对其进行包覆改性研究。通过XRD,TEM,SEM,EDS综合分析可知:Li2ZrO3成功包覆到样品表面。包覆层厚度为3 nm(包覆量1%,质量分数)时复合材料的电化学性能得到显著提升。0.1 C(1 C=200 mAh·g^-1)倍率下首次放电比容量可达271.5 mAh·g^-1,库仑效率为72.4%,降低了首次不可逆容量损失;0.5 C下循环100周次后放电比容量为191.5 mAh·g^-1,容量保持率为89.5%,5 C倍率放电比容量为75 mAh·g^-1,倍率性能提升。适当厚度的均匀Li2ZrO3包覆层可在样品表面形成核壳结构使样品更稳定,减少表面副反应,阻止生成较厚SEI膜,这得益于Li2ZrO3本身的高电导率、高电化学稳定性和较好的锂离子传导性。