锂金属聚合物电池正极材料V2O5的进展

介绍了V2O5的发展概况;论述了溶胶-凝胶法合成非晶态V2O5的研究进展;指出了V2O5作为锂金属聚合物(LMP)电池正极时,存在的大电流放电性能差、容量低、循环寿命短等问题,分析了原因,并给出了解决办法,如V2O5掺杂Ag、Cu、聚吡咯和聚噻吩改性等.     

非晶态V2O5类气凝胶正极材料的性能

以晶态V2O5(c-V2O5)为原料,采用熔融淬冷法制取了非晶态V2O5类气凝胶(a-V2O5ARG-like).XRD、EIS、CV和充放电实验结果说明该样品较c-V2O5有更好的电化学性能;在0.1 C和1 C倍率下放电,其首次放电比容量分别为c-V2O5的1.3倍和1.8倍;循环100次后,容量保持率高达79.5%.     

PEO基聚合物电解质PEOx-Li(C2F5SO2)2N-BaTiO3

研究了以聚环氧乙烷(PEO)为基体,BaTiO3为填充剂,Li(C2F5SO2)2N作为锂盐的聚合物锂离子电池电解质.利用循环伏安法测定了铝的溶解电位,80℃时,铝集流体在PEOx-Li(C2F5SO2)2N体系中溶解电位可达4.1 V(vs.Li/Li+).采用交流阻抗技术测试了其电导率和界面电阻,当x=8时,体系的电导率最大,80℃时为1.65×10-3S/cm,25℃时为1.5×10-5S/cm.     

商业V2O5-WO3/TiO2催化剂SCR脱硝过程中PM2.5的排放特性及影响因素研究

针对V2O5-WO3/Ti O2商用催化剂,采用电称低压冲击器(ELPI)、PM10/PM2.5采样器、X-射线衍射(XRD)、场发射扫描电镜-能谱分析(FSEM-EDX)等对SCR烟气脱硝中形成的细颗粒粒径分布、形貌、元素及物相组成进行了测试分析,并研究了烟气组分及反应条件对SCR脱硝系统出口细颗粒物性的影响。结果表明,SCR脱硝过程中会形成不少亚微米级颗粒,主要成分为硫酸铵以及硫酸氢氨,晶型呈块状。细颗粒生成量随反应温度的升高和NH3/NO摩尔比的增加而增加,在脱硝效率较高时,颗粒物形成量也趋于增多;烟气中SO2、H2O和O2浓度的增加均会导致细颗粒物形成量的增加。导致细颗粒物产生的主要原因可归结于催化剂的活性组分对SO2的氧化以及SCR脱硝反应中NH3的逃逸。     

制备参数对V_2O_5/TiO_2催化剂脱硝性能的影响

研究分析了制备参数对V2O5/TiO2催化剂选择性催化还原脱硝性能的影响,考察了V2O5/TiO2催化剂的抗水抗硫性能。结果表明,载体TiO2的比表面积越大,结晶度越弱,越有利于V2O5/TiO2催化剂上的SCR反应;在煅烧温度为500℃和煅烧时间为5 h的条件下制备的1 wt.%V2O5/TiO2催化剂具有最高的脱硝活性,在典型的SCR反应温度范围(300～400℃),NO转化率达到92.7%～98.8%;随着催化剂上V2O5担载量的增加,有序的V2O5晶体随之增加,反应温度的升高将导致N2O生成量的增多,降低催化剂的选择性;当烟气中含有10%H2O和(0～0.2%)SO2时,对V2O5/TiO2催化剂的脱硝活性影响不大。     

PEO-LiClO4-Li4Ti5O12复合聚合物电解质性能研究

选用钛酸锂(Li4Ti5O12)纳米粒子作为填料对聚环氧乙烷(PEO)基聚合物电解质进行改性。通过交流阻抗谱(EIS),X射线衍射(XRD),扫描电镜(SEM)等手段对材料进行了表征,考察了Li4Ti5O12对聚合物电解质电化学性能的影响。研究表明,Li4Ti5O12的加入减小了聚合物的结晶度,提高了聚合物电解质的电导率,增加了聚合物中得载流子数,PEO16/LiClO4/15%Li4Ti5O12体系30℃电导率达到5.31×10-5S/cm,并初步研究了以此膜为电解质的复合锂硫电池的性能。     

Y2O3掺杂ZnO-Bi2O3压敏瓷的显微组织和电性能

为了提高氧化锌压敏瓷的综合电性能,采用高能球磨制备Y2O3掺杂ZnO压敏瓷,通过扫描电镜和X射线衍射对其显微组织和相成分进行了分析,探讨了Y2O3对氧化锌压敏瓷电性能和显微组织影响机理。结果表明,Y2O3掺杂摩尔分数在0～1.00%时,压敏瓷的电位梯度为332～597V/mm,非线性系数为23.6～40.1,漏电流为0.06～0.90μA。当Y2O3掺杂摩尔分数为0.60%时氧化锌压敏瓷的综合电性能最好,压敏瓷电位梯度为482V/mm,非线性系数为35,漏电流为0.17μA。掺杂Y2O3使压敏瓷晶粒细化是由于Y2O3或者单独以Y2O3氧化物形式存在,钉扎在晶界,阻碍晶粒长大;或者与Bi2O3固溶形成含Y的富铋相,使Bi2O3促进晶粒生长的作用受到抑制。     

V_2O_5/AC脱硝催化剂制备条件的实验研究

采用固定床反应器研究了活性炭负载V2O5(V2O5/AC)催化剂制备过程中各项参数对催化剂脱硝活性的影响。结果表明:HNO3预处理对于V2O5/AC催化剂脱硝活性具有明显的促进作用,最佳的V负载量为3%;活性组分前驱体在450℃以上可完全分解,最佳的预氧化温度为230℃;当温度过高时,活性炭载体在预氧化过程中会与O2反应,同时V2O5会在活性炭表面聚集,从而造成脱硝活性的下降;最佳条件下制备所得V2O5/AC催化剂在实验条件下表现出高度稳定的脱硝性能,脱硝效率达90%。     

P123辅助合成的Li3V2（PO4）3/C的电化学性能

以CH3COOLi、V2O5、H3PO4、草酸以及表面活性剂P123(EO20PO70EO20)为原料,采用液相法合成了亚微米级的Li3V2(PO4)3/C,通过XRD、SEM和电化学性能分析,研究了煅烧温度对产物的影响。用P123辅助合成的Li3V2(PO4)3/C粒径减小,电化学性能提高。在850℃下煅烧合成的Li3V2(PO4)3/C,晶体生长完善,可逆性最好,电荷转移阻抗最小。在3.0~4.3 V循环,0.1C首次放电比容量为128.7 mAh/g,5.0C放电比容量为104.3 mAh/g,容量保持率为81%。     

Li(Ni1/3Co1/3Mn1/3)O2正极材料的电化学性能

用共沉淀法制备出(Ni1/3Co1/3Mn1/3)(OH)2,与LiOH·H2O混合后,在900℃下焙烧12 h,得到锂离子电池正极材料Li(Ni1/3Co1/3Mn1/3)O2.在2.70～4.35 V,电流为40 mA/g时,循环性能稳定.当截止电压升高到4.60 V时,容量可达190 mAh/g.循环伏安实验表明,材料的结构在循环过程中保持稳定.     

Ferroelectric behaviors of sandwich structured PbZr0.52 Ti0.48O3/Pb(Mg1/3Ta2/3)0.7Ti0.3O3/PbZr0.52Ti0.48O3 thin film

Sandwich structured PbZr_0.52Ti_0.48O₃/Pb(Mg_1/3 Ta_2/3)_0.7Ti_0.3O₃/PbZr_0.52Ti_0.48O₃ (PZT/PMTT/PZT) thin films have been successfully synthesized via a combined route involving sol-gel and RF magnetron sputtering. Insertion of the PMTT interlayer effectively suppressed formation of the heterogeneous “rosette” structure of PZT thin film when deposited onto Pt/Ti/SiO₂/Si substrate. While both remanent polarization and coercive field were lowered for the sandwich structured films, the coercive field was reduced more significantly. Such sandwich structured films exhibit improved fatigue behavior and the relative permittivity can not be simply described as a series connection of individual components of perovskite layers.     

1865140型(LiMn2O4+LiNi1/3Co1/3Mn1/3O2)/Li4Ti5O12电池的性能

使用锰酸锂(LiMn2O4)、镍钴锰酸锂(LiNi1/3 Co1/3Mn1/3O2)混合正极材料和钛酸锂(Li4 Ti5 O12)负极材料,制备了中倍率1865140型锂离子电池.制备的电池在12 min内可充满电池容量的80％以上,且电池表面温度不超过35℃;在室温下以2.00 C循环1 200次,容量保持率高于91％;在高温55℃下以1.00 C循环1 000次,容量保持率高于82％.FreedomCAR混合脉冲功率特性表明:在放电深度(DOD) 10％ ～ 70％内、10s脉冲充放电状态下,电池的阻抗都在9 mΩ以下;50％DOD时的10s放电比功率为372 W/kg,充电比功率为520 W/kg.     

YBa2Cu3O7

Some background information on superconducting ceramics is given, and the history of yttrium barium copper oxide (YBCO) is discussed. The crystal structure of superconducting YBCO is described. The production and extraction methods of bulk samples of YBCO are detailed. Different theories of superconductivity in YBCO are addressed, and applications of YBCO superconductors are discussed     

Electromechanical Properties and Morphotropic Phase Boundary of Na0.5Bi0.5TiO3-K0.5Bi0.5TiO3-BaTiO3 Lead-free Piezoelectric Ceramics

The crystal structure and electromechanical properties of two ternary ceramic Na_0.5Bi_0.5TiO₃- K_0.5Bi_0.5TiO₃-BaTiO₃ (NBT-KBT-BT) systems were investigated. A gradual change in crystalline structure and microstructure with the increase of KBT and BT concentrations were observed. It was ascertained that the rhombohedral-tetragonal morphtropic phase boundary (MPB) lies in the range of 0.024 ≰ x ≰ 0.030 for (1–5x) NBT-4x KBT-x BT system and 0.025 ≰ y ≰ 0.035 for (1 − 3y) NBT—2y KBT—y BT system at room temperature. The piezoelectric constant d₃₃ and electromechanical coupling factor k_p of the ceramics attain a maximum value of 150 pC/N and 0.298, respectively. The MPB phase diagram of NBT-KBT-BT ternary system was determined by phase analysis of XRD patterns from calcined specimens. The ferroelectric properties of the (1 − 5x) NBT—4x KBT—x BT system have been characterized. The ternary system ceramics have relatively high Curie temperature T_c.     

混合动力电动车用高效双向直流变换器的设计

针对传统以蓄电池为动力的电动车存在的问题,提出以超级电容加双向DC-DC变换器为辅助动力源的方案。该方案在弥补蓄电池缺陷的同时,提高了整个系统的能源利用效率,并增加了电动车的续驶里程。在简要介绍了超级电容储能系统的基础上,主要研究和设计了系统中的核心部件—双向DC-DC变换器,分析了双向DC-DC变换器的工作模式和控制策略,并对双向变换器进行了软开关分析。Matlab仿真所得的相应波形验证了方案的有效性。     

Textured ferroelectric SrBi2Nb2O9 phase obtained by melt-quenching the SrBi2B2O7-Nb2O5 system and its anisotropic dielectric and pyroelectric properties

Textured SrBi₂Nb₂O₉ ceramics were obtained by quenching the melts of SrBi₂B₂O₇-Nb₂O₅ in equimolar ratio. The as-quenched samples were crystalline comprising 40% c-oriented grains. The influence of the post heat-treatment temperature on the orientation factor (f) and microstructure was studied using x-ray powder diffraction (XRD) and Scanning electron microscopy (SEM). The orientation factor was found to increase with increasing post heat-treatment temperature and reached a maximum value of 65% for the samples heated at 700°C for 10 h. Relative density and the grain-size of the partially grain oriented ceramics were found to increase with an increase in the heat-treatment temperature. The effect of texturing yielded anisotropy in the dielectric and pyroelectric properties. The dielectric constant ( e_r^￠ ( ^) = 114 ) \left( {\varepsilon_r^{\prime } \left( \bot \right) = 114} \right) and the pyroelectric coefficient (p(┴) = −0.07 nC cm⁻² °C⁻¹) along the direction perpendicular to the melt pressing axis were superior to that of the direction parallel ((e_r^￠ ( ||) = 93 \varepsilon_r^{\prime } \left( \parallel \right) = 93 ) (p(||) = −0.02 nC cm⁻² °C⁻¹)) (c-axis of the grain) to the pressing axis at room temperature.     

高温固相法合成Li0.98M0.02Fe0.95V0.05PO4/C的电化学性能

通过高温固相法合成锂离子电池正极材料Li0.98M0.02Fe0.95V0.05PO4/C(M=Mg、Ti、Al、Ni、Zr、Mo和Mn),用XRD、循环伏安(CV)、电化学阻抗谱(EIS)和恒流充放电等方法研究了产物的性能.金属掺杂后的材料,首次充放电比容量均高于未掺杂的纯相材料.在室温下,掺杂Mg的材料在4.2～2.4 V充放电,0.1C首次放电比容量可达154.1 mAh/g,且高倍率充放电比容量高于纯相材料,循环性能稳定,具有较好的电化学性能.     

Studies on Electrical Properties and Magnetoelectric Effect of (x)Ni0.8Cu0.2Fe2O4 + (1?x)Ba0.8Pb0.2Ti0.8Zr0.2O3 Composites

Materials consisting of piezomagnetic and piezoelectric phases viz. Ni_0.8Cu_0.2Fe₂O₄ and Ba_0.8Pb_0.2 Ti_0.8Zr_0.2O₃ have been prepared by standard ceramic method. The presence of two phases in the composites has been confirmed by XRD. Variation of the dielectric constant with frequency in the range 100–1 MHz has been studied at room temperature and the variation of dielectric constant with temperature at set frequencies (1 kHz, 10 kHz, 100 kHz and 1 MHz) has been studied. The dielectric relaxation was observed for the compositions with tetragonal structure whereas normal behaviour was observed for cubic structure. All the samples have shown linear magnetoelectric conversion in the presence of a static magnetic field. The dc resistivity (ρ_DC) was studied as a function of temperature in the range 300–773^∘K. The variation of resistivity with temperature shows metal/seconductor behaviour.     

TiO2包覆LiNi1/3Co1/3Mn1/3O2的高温与高倍率性能

用载体转移工艺制备TiO2包覆的LiNi1/3Co1/3Mn1/3O2(TZ-NC M)材料,产物为层状α-NaFeO2结构,TiO2均匀包覆在LiNi1/3Co1/3Mn1/3O2(NCM)的表面.在2.8～4.3 V循环,TZ-NCM的5.0 C首次放电比容量为111.8 mAh/g;在55℃下以1.0 C循环50次,TZ-NCM的放电比容量为151.0 mAh/g.包覆TiO2能提高高倍率性能、高温稳定性和循环性能.