钙添加剂对可充锌电极性能的影响

通过直接化学反应法,化学共沉淀法以及物理混合方法在可充锌电极活性物质一氧化锌中掺入钙添加剂,研究了锌电极的充放电特必,放电容量及循环寿命等电化学性能,SEM分析表明直接化学反应法制备的样品是基面为四角形的薄片,化学共沉积法制备的样品是基面为六角形的多面体。XRD分析表面两种化学反应方法制备的样品均为锌酸钙晶体,由于制备过程中晶体优先生长方向不同而具有不同的形状。电极充放电实验结果表明,掺钙锌电极的电化学性能明显优于无钙锌电极,化学掺钙对锌电极电化学性能的改善优于物理混合掺钙。X射线照片表明由锌酸钙组成锌电极的表面活性物质分布较均匀,不掺钙的锌电极经多次充放电循环后电极表面已基本上没有活性物质。     

Effects of additives on zinc electrodeposition from alkaline zincate solution

The effects of additives on the surface and cross-sectional morphologies of zinc deposits on iron substrate from alkaline zincate solution were characterized by scanning electron microscope (SEM). The cathodic reaction mechanisms under various concentrations of additives were investigated using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques. It is found that with increasing the additive A content in the bath solution, the nucleation overpotential (NOP) value is obviously increased and the inhibition effect is strengthened. This may be mainly due to the adsorption of additive A on the cathodic electrode surface, which can cover the active sites and block the discharge reduction. The results of EIS analysis indicate that the rate-determining step of zinc electrodeposition process is changed from mixed control step into electrochemical reduction step in the presence of additive A. However, any quantity of additive B has little effect on the NOP value and the inhibition effect is not obvious. Furthermore, addition of additive A and additive B at the same time displays the strongest inhibition effect and shows a strong synergism because of their co-adsorption on the cathodic electrode surface.     

添加剂对锌电极性能的影响(英文)

为了改善镍锌电池的性能,同时研究电极中添加剂对锌电极性能的影响,选用正交设计对影响锌电极的4个因素(乙炔黑、Bi2O3、PbO、包覆La(OH)3的Ca[Zn(OH)3]2·2H2O)选择3个水平进行测试。对没有任何添加剂的氧化锌在20%KOH电解液中进行充放电循环实验,研究添加剂的作用。为了更好地解释锌电极放电容量衰减的原因,对正交实验的最差样品和最优样品放电产物所含的Zn和Ca的比例进行分析。通过表征,得出了在该实验条件下的电极添加剂的最优配比方案为:在5g样品中,乙炔黑0.02g,Bi2O3 0.5g,PbO 0.3 g,包覆La(OH)3的Ca[Zn(OH)3]2·2H2O)0.2g。     

Effects of Na+ doping on crystalline structure and electrochemical performances of LiNi0.5Mn1.5O4 cathode material

Pristine LiNi_0.5Mn_1.5O₄ and Na-doped Li_0.95Na_0.05Ni_0.5Mn_1.5O₄ cathode materials were synthesized by a simple solid-state method. The effects of Na⁺ doping on the crystalline structure and electrochemical performance of LiNi_0.5Mn_1.5O₄ cathode material were systematically investigated. The samples were characterized by XRD, SEM, FT-IR, CV, EIS and galvanostatic charge/discharge tests. It is found that both pristine and Na-doped samples exhibit secondary agglomerates composed of well-defined octahedral primary particle, but Na⁺ doping decreases the primary particle size to certain extent. Na⁺ doping can effectively inhibit the formation of Li_xNi_1–xO impurity phase, enhance the Ni/Mn disordering degree, decrease the charge-transfer resistance and accelerate the lithium ion diffusion, which are conductive to the rate capability. However, the doped Na⁺ ions tend to occupy 8a Li sites, which forces equal amounts of Li⁺ ions to occupy 16d octahedral sites, making the spinel framework less stable, therefore the cycling stability is not improved obviously after Na⁺ doping.     

钴酸锂的再生及其电化学性能

采用提取的含少量Co3O4的LiCoO2为原料,在不同温度下合成正极材料LiCoO2,烧结时间为12 h,并采用XRD和SEM技术研究合成的LiCoO2的晶相结构与微观形貌。结果发现:烧结温度对LiCoO2的晶体结构影响较大,烧结温度越高,LiCoO2的层状结构发育越完整。循环伏安曲线很好地反映了再生LiCoO2的脱/嵌锂行为。将LiCoO2样品做成电池进行电化学检测,结果发现,烧结温度为850℃的样品首次放电容量为151mA.h/g,30次循环之后,放电容量仍有141mA.h/g,表现出良好的电化学性能。     

Preparation and electrochemical performance of nano-scale Ni(OH)2 doped with zinc

Nano-scale Ni(OH)₂ doped with Zn was prepared by precipitation transformation method and characterized by XRD and TEM. The electrochemical performance was investigated by cyclic voltammetry (CV) and constant current technology. The measurement results indicate that the lattice parameters of nano-scale Ni(OH)₂ are changed and the agglomeration of particles becomes obvious with the increased Zn-doped content. Compared with un-doped one, the discharge specific capacities of nano-scale Ni(OH)₂ doped with 10% Zn are enhanced by 8% and 6%, respectively, at the discharge rate of 0.2C and 3C. After 110 cycles, the discharge specific capacity of the sample doped with 10% zinc is still above 85% of its initial capacity discharged at 0.2C. Therefore, a suitable Zn-doped content is beneficial to improving the discharge performance of nano-scale Ni(OH)₂.     

添加Si对A_2B_7型电极合金结构及电化学贮氢性能的影响(英文)

为改善La–Mg–Ni系A2B7型合金的电化学贮氢性能,在合金中添加一定量的Si元素,通过真空熔炼及退火处理的方法制备La0.8Mg0.2Ni3.3Co0.2Six(x=0-0.2)电极合金。研究Si元素的添加对合金结构及电化学贮氢性能的影响。结果表明,铸态及退火态合金均为多相结构,分别为Ce2Ni7型的(La,Mg)2Ni7相和CaCu5型的LaNi5相以及少量的残余相LaNi3。Si元素的添加没有改变合金的主相,但使得合金中的(La,Mg)2Ni7相减少而LaNi5相增加。添加Si显著地影响了合金的电化学性能。随着Si含量的增加,铸态及退火态合金的放电容量逐步降低,但循环稳定性却随着Si含量的增加而增强。此外,合金电极的高倍率放电性能、极限电流密度、氢扩散系数以及电化学交流阻抗谱的测试均表明合金的电化学动力学性能随着Si含量的增加先增加而后减小。     

Design of best performing hexagonal shaped Ag@CoS/rGO nanocomposite electrode material for electrochemical supercapacitor application

The mixed metal/metal sulphide (Ag@CoS) with reduced graphene oxide (rGO) nanocomposite (Ag@CoS/rGO) was synthesized for the possible electrode in supercapacitors. Ag@CoS was successfully deposited on the rGO nanosheets by hydrothermal method, implying the growth of 2D Ag and CoS-based hexagonal-like structure on the rGO framework. The synthesized nanocomposite was subjected to structural, morphological and electrochemical studies. The XRD results show that the prepared nanocomposite material exhibits a combination of hexagonal and cubic phase due to the presence of CoS and Ag phases together. The band appearing at nearly 470.33 cm⁻¹ in FTIR spectra can be ascribed to the absorption of S–S bond in the Ag@CoS/rGO nanocomposite. The clear hexagonal structure was analysed by SEM and TEM with the grain sizes ranging from nanometer to micrometer. The electrode material exhibits excellent cyclic stability with a specific capacitance of 1580 F/g at a current density of 0.5 A/g without any loss of capacitive retention even after 1000 cycles. Based on the electrochemical performance, it can be inferred that the prepared novel nanocomposite material is very suitable for using as an electrode for electrochemical supercapacitor applications.     

CO还原氧化锌生成气态锌和CO2反应的平衡常数

用新方法测定了不同温度下ＣＯ还原ＺｎＯ生成Ｚｎ蒸气和ＣＯ２的反应的平衡常数,得到了该反应的ｌｇＫｐ＝－１０６３０／Ｔ＋６．９２关系式。将此式与文献报道的关系式进行比较,在１２５０Ｋ时,Ｋｐ最小值为０．０１２４,比本研究低０．０１３６;Ｋｐ最大值为０．０３２４,比本研究高０．００６４;其余的Ｋｐ值与本研究的结果比较接近,差值不超过０．００５,说明本研究结果是可靠的。     

热处理对冷喷涂锌镍涂层组织结构及电化学性能的影响

采用低压冷喷涂技术在45号钢表面制备以镍为主的镍-锌-氧化铝复合涂层,对锌镍复合涂层进行锌熔点以上20℃热处理,并与未热处理涂层进行对比,利用SEM观察其表面和截面形貌,通过天然海水浸泡以及电化学阻抗的方法对其进行了腐蚀防护性能测试。结果表明,热处理后涂层中锌粉末的球形结构基本消失,均匀分布在在涂层中;开路电位稳定在-1200 m V(相对SCE)左右;对于热处理涂层,模拟电路中的电阻值在50~100 kΩ·cm2范围内浮动,电阻值扩大了一个数量级,明显比未热处理过的涂层电阻大,耐腐蚀性有所提高。     

Effects of rapid quenching on structure and electrochemical characteristics of La0.5Ce0.2Mg0.3Co0.4Ni2.6-xMnx （x=0-0.4） electrode alloys

The La-Mg-Ni system PuNi3-type La0.5Ce0.2Mg0.3Co0.4Ni2.6-xMnx (x=0, 0.1, 0.2, 0.3, 0.4) hydrogen storage alloys were prepared by casting and rapid quenching. The effects of the rapid quenching on the structure and electrochemical characteristics of the alloys were studied. The results obtained by XRD, SEM and TEM indicate that the as-cast and quenched alloys mainly consist of two major phases, (La,Mg)Ni3 and LaNi5, as well as a residual phase LaNi. The rapid quenching does not exert an obvious influence on the phase composition of the alloys, but it leads to an increase of the LaNi5 phase and a decrease of the (La, Mg)Ni3 phase. The as-quenched alloys have a nano-crystalline structure, and the grain sizes of the alloys are in the range of 20-30 nm. The results by the electrochemical measurements indicate that both the discharge capacity and the high rate discharge(HRD) ability of the alloy first increase and then decrease with the variety of quenching rate and obtain the maximum values at the special quenching rate which is changeable with the variety of Mn content. The rapid quenching significantly improves the cycle stabilities of the alloys, but it slightly impairs the activation capabilities of the alloys.     

pH值及助剂对氢化态Mg-Mn复合物水反应性能的影响

为了提高氢化态Mg-Mn复合物的水反应性能,采用改变反应水溶液pH值和在水溶液中加入不同助剂的方法,通过测量反应过程中不同时刻产生的氢气量对助剂在水反应中的作用进行表征,利用SEM和XRD等测试手段对反应产物进行表征和测试,对反应机理进行分析。结果表明：改变反应溶液的pH值对反应程度及放氢速率的影响不大,且pH值越大,越不利于反应的进行;在溶液中添加助剂焦磷酸钾、六偏磷酸钠、羟基乙叉二膦酸(HEDP)对提高氢化态Mg-Mn复合物的放氢速率有显著促进作用;相比之下,应采用添加磷酸盐助剂的方法来改善氢化态Mg-Mn复合物水反应性能。     

Crystal structure and electrochemical behaviors of Pt/mischmetal film electrodes

The Ml(La-rich mischmetal0films with a thin Pt layer on the substrate of chemically coarse ITO glass or silicon slices were prepared by magnetic sputtering tchnique.The crystal structure and surface morphology of the films were investigated by X-ray diffraction(XRD)analysis and atomic force microscopy(AFM),respectively, The electrochemical hydridation/dehydridation behaviors of the films in KOH solution were studied by using cyclic voltammagraph and electrochemical impedance spectrum(EIS)as well.The AFM results show that the Pt cover layer on the M1 films is of island structure with a grain of 150-200nm in size.The presence of a thin Pt layer can provide sufficient high electrocatalytic activity for the electrochemical charge-transfer reaction.The electrochemical reduction and oxidation reaction occur on the Pt layer,and the diffusion of H into the Ml film is the rate-controlled step.The Pt coatings also act as protective layers,preventing oxidation and/or poisoning of the underlying Ml films in air.     

纳米氧化锌对镍氢电池电化学性能的影响

采用均匀沉淀法制备纳米氧化锌,将其作为添加剂掺杂制备MH/Ni电池正极,研究正极中添加不同质量分数的纳米ZnO对电极电化学性能的影响,初步探讨纳米氧化锌在电极内部的反应机制。结果表明,掺杂后氢氧化镍电极的导电性提高,电化学活性增强,有效地提高了活性物质的利用率,改善了电极反应的传质和传荷条件,使电极中电活性粒子具有合理的分布,因而显示出良好的电化学性能。经过比较,添加质量分数为4%的纳米ZnO电化学性能最佳,在60周和80周时放电容量仍有282和272mAh·g-1,而且放电平台较高。     

Ga和Bi对Al-Zn-Sn牺牲阳极电化学性能的影响(英文)

通过光学显微镜(OM)、扫描电镜(SEM)、能谱分析(EDAX)和电化学性能测试等方法,研究了Ga和Bi对Al-7Zn-0.1Sn(质量分数,%)牺牲阳极微观组织和电化学性能的影响。Al-Zn-Sn合金加入Ga和Bi元素后,合金组织由粗大枝晶转变为等轴晶,仅剩下少量枝晶。Al-7Zn-0.1Sn-0.015Ga-0.1Bi合金具有高的电流效率(97%)和均匀的腐蚀形貌,表明添加适量的Ga和Bi元素能有效改善Al-Zn-Sn合金的组织和电化学性能。     

碳化钙骨架碳负极材料的制备及电化学性能

以碳化钙为原料、新鲜氯气为刻蚀剂,在400～700℃范围内制备碳化钙骨架碳作为锂离子电池新型负极材料.用X射线衍射(XRD)、扫描电镜(SEM)、氮气吸附实验、恒流充放电、交流阻抗(EIS)等对碳化钙骨架负极材料进行表征及电化学性能测试,并探讨制备温度对碳化钙骨架碳结构和电化学性能的影响.结果表明:所有温度下制备的碳化钙骨架碳均为无定形碳材料,但随着制备温度的升高,材料出现部分石墨化倾向;600℃制备的碳化钙骨架碳具有良好的电化学性能,在0.1 C充放电时,首次放电比容量为890.9 mA·h/g,可逆容量为335.4mA·h/g,循环30次后的可逆容量为266.8 mA·h/g.     

轧制温度对Pb/Al复合电极材料电化学性能的影响

采用浇铸法制备出Pb/Al复合电极材料,分别在室温和250 ℃下进行轧制。利用扫描电子显微镜、电化学工作站、四电子探针等,对Pb/Al复合电极材料的界面、电化学性能及导电性能进行分析。结果表明：浇铸轧制Pb/Al复合电极材料得到了界面冶金式结合,与浇铸Pb/Al复合电极材料相比,界面结合明显改善;浇铸常温轧制Pb/Al复合电极材料有着较优的电化学性能和导电性能,与浇铸250℃轧制Pb/Al复合电极材料、浇铸Pb/Al复合电极材料、传统Pb-Ag合金电极相比,极化电位分别降低2.4%、4.7%、9.8%,导电性能分别提高2.7%、6.8%、13.9%。     

Effect of photocatalyst on performance of LaNi5 hydrogen storage alloy electrodes

Photocatalyst hydrogen storage alloys（PHSA） with different photocatalyst contents were synthesized by mechanical blend method. The effects of the photocatalyst on the electrochemical performance of the PHSA were studied. The resutts indicate that the PHSA electrodes show better activation performance when UV irradiation is present. The high rate discharge performance as well as cycle performance is improved compared with that of the AB5 alloys, The PHSA shows the best performance when the photocatalyst content is 20%.     

电沉积工艺对镀锌层的表面形态及电化学性能的影响

采用电沉积技术制备几种电沉积式锌电极,考察镀液中KOH浓度和沉积电流密度对所制得镀锌层的微观形貌与性能的影响规律.结果表明镀锌层的枝晶随着KOH浓度(250～400 g/L)的增加而变得粗大,且其析氢量、腐蚀电位和腐蚀电流密度均呈现先减小而后增加的趋势;随着电流密度(25～100 mA/cm2)的增长,镀锌层由块状结晶向枝晶转变,相应地电极反应活性随之增大,而耐蚀性则随之变差,并发现沉积电流密度为75 mA/cm2时,锌电极的综合性能最好,以200 mA/g充放电循环10周次,其放电容量仍可达504 mA-h/g.解释了主要工艺参数对结晶形态及电极性能影响的原因,并说明适当的KOH浓度和沉积电流密度有利于提高电极的综合性能.     

碳包覆氧化镍纳米颗粒制备与电化学性能研究

采用直流电弧放电等离子体技术制备了核壳结构碳包覆氧化镍纳米颗粒,并采用X射线衍射、高分辨透射电子显微镜、X射线能量色散分析谱仪和表面物理吸附仪等测试技术对样品的微观结构进行研究。并利用循环伏安法、恒电流充放电以及交流阻抗等技术研究其作为超级电容器电极材料的电化学性能。结果表明:直流电弧等离子体技术制备的碳包覆氧化镍纳米颗粒具有典型的核壳结构,内核为面心立方结构的氧化镍纳米颗粒,外壳为碳层。颗粒形貌主要为立方体结构,粒度均匀,分散性良好,粒径分布在30～70 nm范围,平均粒径为50 nm,外壳碳层的厚度为5 nm。碳包覆氧化镍纳米颗粒具有较高的比容量和良好的电化学活性。