硼掺杂对稀土贮氢合金相结构和电化学性能的影响

研究了用B掺杂替代A1对AB5型稀土贮氢合金相结构和电化学性能的影响.对M1Ni3.55Co0.75Mn0.4Al0.3-xBx(x=0,0.1,0.2,0.3)合金的研究结果表明:掺B后贮氢合金出现了CeCo4B第二相,导致贮氢合金的电化学容量下降;随B含量的增加和A1含量的减少,氢的扩散系数明显上升,合金的极化电阻减小,合金的高倍率放电性能和低温性能得到明显改善.     

锰离子掺杂对LiCoPO_4性能的影响

应用溶胶-凝胶法合成了锰掺杂的LiCoPO4正极材料.X射线衍射、扫描电镜和循环伏安等电化学测试表明,少量锰离子掺杂不影响LiCoPO4的晶格结构,且明显改善了LiCoPO4正极材料电化学性能.锰掺杂量为1%时得到的LiMn0.01Co0.99PO4正极材料具有最好的电化学性能,以0.1C倍率放电时,首次放电比容量可达130.6 mAh/g.     

Mg、Ti离子复合掺杂改性磷酸铁锂正极材料及其电池性能

在氮气气氛下采用高温固相方法, 合成了Mg、Ti 离子复合掺杂改性的锂离子电池正极材料(Li_0.98Mg_0.01)(Fe_0.98Ti_0.01)PO₄/C, 并通过粉末X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)和充放电循环对材料进行性能表征. 测试结果表明, 复合离子掺杂可显著改善材料的电化学性能, 模拟电池在0.2C和1C倍率下的放电比容量分别为154.7 和146.9 mAh·g^-1. 以此复合掺杂样品为正极材料组装60 Ah动力电池, 其3C倍率放电容量仍保持为1C倍率放电容量的100%; 低温0 和-20 °C测试条件下, 动力电池放电容量分别保持为常温初始放电容量的89.7%和63.1%; 在常温1C/1C充放电条件下, 经过2000次循环后, 电池容量依然保持为初始放电容量的89%, 显示出优良的倍率放电性能和循环性能. 研究结果表明, Mg、Ti 离子复合掺杂改性的磷酸铁锂正极材料及其电池具有优良的放电性能和循环稳定性, 可广泛应用于电动(或混合动力)汽车和储能电池系统.     

复合掺杂改性的尖晶石LiMn1.98Cr0.02O4-yCly的研究

采用改进的高温固相法合成了阴阳离子复合掺杂改性的锂离子电池尖晶石结构正极材料LiMn1.98Cr0.02O4-yCly(y=0, 0.01, 0.02, 0.03, 0.04, 0.05, 0.10). 采用X射线衍射手段对材料的晶体结构进行了表征. 从材料的晶体结构、充放电容量、循环性能和倍率放电特性等方面分析了复合掺杂在稳定晶体结构和改善材料电化学性能方面的作用. 实验结果表明, 由于复合掺杂的综合作用, 改性后的材料既保持了高的初始容量, 又具有优良的循环性能, 倍率放电性能也得到了有效的改善. 其中LiMn1.98Cr0.02O3.96Cl0.04的综合性能最优, 初始放电比容量达到127 mA·h/g以上, 循环50次后仍有110 mA·h/g的放电比容量.     

稀土对LaNi_(3.5)Co_(0.8)Mn_(O.4)Al_(0.3)合金电化学及储氢特性的影响

研究了以Ce,Nd和Pr部分替代LaNi(3．5)Co(0.8)Mn(0.4)Al(0.3)中的La后对合金电化学及储氢特性的影响。稀土含量的变化明显改变合金的电化学及储氢特性。Pr对合金的电化学性能影响小于Ce。Ce使合金的放电容量降低,并升高合金的氢分解压。随着Nd含量的增加,合金的放电容量降低。     

锂离子电池正极材料Li_(1.2)Mn_(0.54-x)Ni_(0.13)Co_(0.13)Zr_xO_2的制备及电化学性能

为了改善富锂锰基正极材料Li1.2Mn0.54Ni0.13Co0.13O2的循环性能,采用燃烧法合成了正极材料Li1.2Mn0.54-xNi0.13Co0.13ZrxO2(x=0.00,0.01,0.02,0.03,0.06).通过X射线衍射(XRD)和扫描电镜(SEM)对其结构与形貌进行了表征,利用恒电流充放电测试,循环伏安(CV)及电化学交流阻抗谱(EIS)技术对其电化学性能进行测试.结果表明,Li1.2Mn0.54-xNi0.13Co0.13ZrxO2(x=0.00,0.01,0.02,0.03,0.06)正极材料均具有α-NaFeO2型层状结构;在室温,2.0-4.8 V电压范围,以0.1C和1.0C(充放电电流以1.0C=180 mA·g-1计算)倍率充放电进行测试,样品Li1.2Mn0.52Ni0.13Co0.13Zr0.02O2的首次放电比容量分别为280.3和206.4 mAh·g-1.其中,在1.0C倍率下,100次循环后容量保持率由原来的73.2%提高到88.9%;以5.0C倍率充放电进行测试,经50次循环后,掺杂正极材料的放电比容量为76.5 mAh·g-1,而未掺杂材料仅有15.0 mAh·g-1.在50、25和-10°C,2.0C倍率条件下,掺杂正极材料的电化学性能均得到有效改善,其中,在-10°C经过50次循环后正极材料Li1.2Mn0.52Ni0.13Co0.13Zr0.02O2比未掺杂的正极材料相比,其放电比容量提高了61.1%.     

镁对La1-xMgxNi2.5Co0.5（x=0～0.4）合金循环过程中电化学性能的影响

采用充放电测试、高倍率放电等方法,系统分析了Mg对合金在循环过程中的电化学性能影响规律,结果表明La1-xMgxNi2.5Co0.5(x=0～0.4)合金在初始阶段的高倍率放电性能随着Mg含量的增加先增大后减小,La1-xMgxNi2.5Co0.5(x=0～0.4)合金经90次循环后的放电容量保持率先从x=0时的28.0%增加到x=0.2时的59.1%,然后下降到x=0.4时的45.7%。     

纳米氧化铜掺杂对储氢合金电极性能的影响

采用纳米氧化铜作为添加剂制备储氢合金电极, 考察了氧化铜对储氢合金电池储备容量的调节作用, 分析了掺杂后电极及电池质量的变化, 研究了掺杂合金电极的电化学性能, 并用SEM、EIS、CV等方法分析了反应的电化学机理. CV、SEM结果表明, 氧化铜在首次充电过程中被还原成低价态沉积在合金颗粒表面, 由于氧化铜比容量远大于合金, 可以通过掺杂氧化铜调节合金的储备容量. 电化学测试结果表明, 掺杂合金电极具有更好的高倍率充放电能力和循环性能. EIS分析结果表明, 掺杂合金电极导电性增强, 电化学活性提高.     

La0.5Mg0.5(Ni1-xCox)2.28(x=0.0～0.2)储氢合金的相结构和电化学性能

用冷坩埚磁悬浮熔炼方法制备La0.5Mg0.5(Ni1-xCox)2.28(x=0.0～0.2)贮氢电极合金,采用SEM,EDS,XRD,P-C-T测试及三电极电化学性能测试研究合金的相成分、相结构、P-C-T曲线和电化学性能.EDS结合XRD分析表明,La0.5Mg0.5Ni2.28及La0.5Mg0.5(Ni0.85Co0.15)2.28合金主相均为MgSnCu4型的LaMgNi4相,还包括LaNi5和(La,Mg)Ni3相.P-C-T曲线显示,合金均有双放氢平台,合金的贮氢量由Co替代量x=0.0时的1.24%增大至极大值x=0.15时的1.27%.电化学性能测试表明,随Co含量增加,最大放电容量从329.0mAh·g-1(x=0.0)增大到337.5 mAh·g-1(x=0.15),合金活化性能及高倍率放电性能明显改善;循环稳定性无明显变化.     

含锡AB_5型非化学计量贮氢合金Ⅱ.电化学性能

研究了几种AB5非化学计量贮氢合金的电化学性能 ,及在低电流密度与高电流密度放电下取代元素对放电比容量、活化性能及循环寿命的影响。Sn ,Co,Mn的加入有利于提高合金的电化学贮氢容量 ,La(NiSn) 5.14 ,La(NiSnCo) 5.12 和La(NiSnMn) 5.12 具有相同的电化学贮氢容量与活化特性。尽管La(NiSn) 5.14 大电流放电性能优于La(NiSnCo) 5.12 和La(NiSnMn) 5.12 ,但其寿命短。Mn ,Co和Al可大大提高合金的使用寿命。La(NiSnCo) 5.12 被认为是一种理想的贮氢合金。     

Electrodeposition of Ni and Te‐doped Cobalt Triantimonide in Citrate Solutions

Skutterudite compounds form a new class of potential candidates for thermoelectric applications. Cobalt triantimonide (CoSb₃) shows good thermoelectric properties at medium and high temperatures. Doping this system with substitution elements, for either Co or Sb or both, may result in an increase of the thermoelectric figure of merit (ZT). This work focused on the electrochemical doping and characterization of films and nanowires of Co‐Sb system in citrate solutions using gold‐coated PCTE templates. The electrodeposition was performed on gold surface that was pre‐treated electrochemically to ensure reproducible results. The electrochemical treatment acted as an annealing process for the surface, which resulted in an increase in Au(111) as demonstrated by XRD. Detailed electrochemical studies including deposition‐stripping experiments was performed in order to develop a better understanding of the co‐deposition kinetics and a better control over the composition of doped Co‐Sb system. Scanning electron microscopy (SEM/EDS) helped study the morphology and the composition of the doped and undoped Co‐Sb system. Co‐deposition of Co‐Sb showed that the amount of Co is higher in nanowires than in film or mushroom caps due to the slow Sb deposition rate dictated by slow Sb(III) complex diffusion. Doped nanowires have been also obtained. Both Ni and Te electrochemical doping of the Co‐Sb system affected the composition of the deposit but there was no effect on nanowire morphology.     

The effect of ZnO addition on the electrochemical properties of the LaNi3.55Mn0.4Al0.3Co0.2Fe0.55 electrode used in nickel–metal hydride batteries

Journal of Solid State Electrochemistry - The studied electrochemical properties of the LaNi3.55Mn0.4Al0.3Co0.2Fe0.55 alloy showed a rather poor performance. To improve them, ZnO, a doping agent at...     

超细钴掺杂二氧化钛的制备、表征及气相光催化性能

以四氯化钛为原料、硝酸钴为掺杂剂,制备了粒径10 nm～30 nm的钴掺杂超细二氧化钛并进行了XRD、TEM和FT-IR表征及气相光催化性能的评价。钴掺杂造成了锐钛矿向金红石相的转变温度明显降低,掺杂量从0增加到4%时,相变温度下降了90 ℃左右。制备过程中的pH值对相变也有影响,pH值很小时相变在较低的温度下就能发生。当pH<3,500 ℃焙烧的样品中就基本是金红石型TiO2;红外光谱分析证明掺杂样品比纯样品有更强的吸水性;以苯作为反应物在一个固定床光反应器中考察了钴掺杂二氧化钛的光催化活性。结果表明,钴掺杂对催化剂的光催化性能有影响。反应初期掺杂样品与纯二氧化钛样品相比活性相差不大,但随着反应的进行活性差别逐渐增大。在实验条件下160 min后纯样品基本失活,掺杂样品的活性仍大于50%。     

Effects of Ti and Co on the Electrochemical Characteristics of MgNi-Based Alloy Electrodes

Mg-based hydrogen storage alloys MgNi, Mg0.9Ti0.1Ni and Mg0.9Ti0.1Ni0.9Co0.1 were successfully prepared by means of mechanical alloying （MA）. The structure and the electrochemical characteristics of these Mg-based materials were also studied. The results of X-ray diffraction （XRD） and scanning electron microscopy （SEM） show that the main phases of the alloys exhibit amorphous structures, and trace of Ni co-exists. The charge-discharge cycle tests indicate these alloys have good electrochemical active characteristics. And the cycle stability of Ti and Co doped alloy was better than that of MgNi alloy. After 50 cycle charge-discharge, the discharge capacity of the Mg0.9Ti0.1Ni0.9Co0.1 alloy was much better than that of MgNi and Mg0.9Ti0.1Ni alloys. The discharge capacity of Mg0.9Ti0.1Ni0.9Co0.1 was 102.8% higher than that of MgNi alloy, and 45.49% higher than that of the Mg0.9Ti0.1Ni alloy. During the process of charge-discharge cycle test, the main reason for the electrode capacity fading is the corrosion of Mg to Mg（OH）2 on the surface of alloys. The Tafel polarization test indicates Ti and Co improve the anticorrosion in an alkaline solution. The EIS results suggest that proper amount of Ti and Co doping improve the electrochemical catalytical activity on the Mg-based alloy surface significantly.     

Design and synthesis of nitrogen-doped hexagonal NiCoO nanoplates derived from Ni-Co-MOF for high-performance electrochemical energy storage

In order to further improve the potential application of nickel-cobalt oxide (NiCoO) in supercapacitors, we use controlled calcination of different Ni-Co-MOF ([NiCo(HBTC)(4,4′-bipy)]) composites to obtain five kinds of nickel doped NiCoO (N-NiCoO) with different Ni/Co molar ratio. These N-NiCoO materials with unique hexagonal nanoplates structure, high specific surface area and high porosity indicate high and stable electrochemical activity. In particular, N-NiCoO-2 with a Ni/Co molar ratio of 2:1 exhibits the highest 945.79 F/g specific capacitance at 1 A/g and a high cycle stability of only 6.7% attenuation after 5000 cycles. Apart from the certain percentage of NiCoO with higher conductivity, nitrogen doping provides more reactive sites and the specific porous hexagonal nanoplates structure of the product itself accelerate electron transfer and promote electrolyte diffusion can more effectively enhance the electrochemical performance. Therefore, N-NiCoO synthesized via a simple method exhibit exciting potential and can be used as an electrode material for supercapacitors with good performance.     

S-M(M=Cu, Co, Ti)复合掺杂层状LiMnO2 的合成及其电化学性能

用水热法合成了锂离子电池正极材料正交结构LiMnO2材料, 并对其进行S2－、大尺寸阳离子(Cu2＋, Co3＋, Ti4＋)以及硫-金属离子复合掺杂改性. 用X射线衍射(XRD)、X光电子能谱分析(XPS)、透射电子显微镜(TEM)、恒电流充放电、交流阻抗谱(EIS)等测试技术进行表征. 实验结果表明: 当掺入离子的含量较低时, 得到的产物能保持完整的正交结构, 并表现出较好的电化学性能. S2－和非Jahn-Teller效应大尺寸阳离子的掺入使材料的循环稳定性能大幅度提高, 而这种提高是源于这些离子对LiMnO2结构的稳定作用. 电极材料Li1.02Mn0.988Ti0.012O1.989S0.011显示了最优的电化学性能, 在50 mA•g－1放电速率下, 其初始放电容量为142.6 mAh•g－1, 60次循环后放电容量为213.4 mAh•g－1. 硫-金属阳离子复合掺杂, 综合了大尺寸阳离子可以提高材料中Li＋的扩散能力和S2－掺杂抑制Jahn-Teller畸变两方面优势, 使层状结构LiMnO2正极材料既保持了较高的容量又获得良好的循环性能.     

组合法优化Ti掺杂Zn-Al合金薄膜的耐腐蚀性能

应用组合技术, 通过离子束溅射法制备了Zn-Al-Ti合金薄膜材料芯片(其中wAl:wZn=55%:45%(w, 质量分数)), 表征了热处理后薄膜的耐腐蚀性能, 研究了Ti掺杂量对薄膜耐腐蚀性能的影响. 在Ar+5%(φ, 体积分数)H2混合气氛中, 经200 ℃扩散1 h, 再经370 ℃热处理2 h后可以得到高质量的合金薄膜. 通过X射线衍射仪(XRD)和扫描电子显微镜(SEM)分别对热处理后的典型样品进行相结构和形貌表征. 使用电化学方法测试样品的耐腐蚀性能. 结果表明, Ti适量掺杂样品的腐蚀速率明显下降, 其中Ti掺杂量为6.0%(w)的Zn-Al-Ti合金薄膜(94.0%(w) Zn-Al, 其中wAl:wZn=55%:45%)具有最优异的耐腐蚀性能, 其原因在于, Ti适量掺入后晶粒明显细化, 表面更为致密, 且钝化作用增强.     

Synthesis of Phosphorus‐Doped Graphene and its Wide Potential Window in Aqueous Supercapacitors

Phosphorus‐doped (P‐doped) graphene with the P doping level of 1.30 at % was synthesized by annealing the mixture of graphene and phosphoric acid. The presence of P was confirmed by elemental mapping and X‐ray photoelectron spectroscopy, while the morphology of P‐doped graphene was revealed by using scanning electron microscopy and transmission electron microscopy. To investigate the effect of P doping, the electrochemical properties of P‐doped graphene were tested as a supercapacitor electrode in an aqueous electrolyte of 1 M H₂SO₄. The results showed that doping of P in graphene exhibited significant improvement in terms of specific capacitance and cycling stability, compared with undoped graphene electrode. More interestingly, the P‐doped graphene electrode can survive at a wide voltage window of 1.7 V with only 3 % performance degradation after 5000 cycles at a current density of 5 A g^?1, providing a high energy density of 11.64 Wh kg^?1 and a high power density of 831 W kg^?1.     

Electron field emission of iron and cobalt‐doped DLC films fabricated by electrochemical deposition

Using a simple electrochemical depositing process, iron and cobalt‐doped diamond‐like carbon (DLC) films were deposited on Si (100) substrates. The results showed that metallic elements were inhomogeneously doped into highly cross‐linking amorphous carbon matrix, forming the typical nanocrystalline/amorphous nanocomposite structure, and simultaneously the microsturcture of amorphous carbon was changed by the doping of metals. Field emission performance showed that the incorporation of iron and cobalt effectively decreases the threshold field from 13.5 V/µm to 8.0 V/µm and 6.5 V/µm, respectively, and a highest current density of the Co‐DLC film was about 1.2 mA/cm² at the electric field of 23.5 V/µm. Copyright © 2012 John Wiley & Sons, Ltd.     

Performance of SnSb:Ce,Co alloy as anode for lithium-ion batteries

Synthesis of pure tin-antimony (SnSb) by co-precipitation method using metal chlorides as starting materials and Ce, Co-incorporated SnSb is reported and examined. The structure of the doped SnSb is compared with the pure SnSb by means of XRD analysis in which no structural variation is observed. Strain analysis is carried out by Williamson-Hall (WH) plot method. Compared to the intact SnSb, diminutive decrement in unit cell volume is observed for the doped SnSb, which indicates the rigidity of the structure after doping. The electrochemical properties are analyzed by cyclic voltammetry, electrochemical impedance spectroscopy, and reversibility testing. Improved redox activity and reversibility are observed for SnSb:Ce, Co anode due to the well-resolved grain and grain boundary regions. Doped anode exhibits specific capacitance around 319 Fg^?1 for 50 cycles. The augmented capacity and electrical conductivity of the SnSb:Ce, Co anode will enhance the rate capability of it, and this makes SnSb:Ce, Co a promising anode material for solid-state lithium-ion batteries in energy systems.