过渡金属二硼化物作为高容量负极的研究

碱性溶液中,VB2和TiB2分别发生了 11电子和 6电子氧化反应,释放出 3 100mAh/g和 1 600mAh/g的超常电化学容量.对此,初步的解释是:在二硼化物中过渡金属与硼的电子转移使硼元素电负性增强,引起硼的电化学活化.使得合金的电极电势钳制在较负区域,导致某些过渡金属元素处于活化态,进而发生电化学氧化释放出电化学能量.     

LiV3O8在Li2SO4水溶液中的电化学性能

采用低温固相法合成了具有纳米结构的LiV₃O₈材料.扫描电子显微镜（SEM）及透射电子显微镜（TEM）测试显示该材料具有纳米结构.X射线衍射（XRD）表明该材料属于单斜晶系,P2₁Im空间群.并采用循环伏安法（CV）及电化学阻抗谱图测试对该材料在1、2 mol·L^-1Li₂SO₄水溶液及饱和Li₂SO₄水溶液中的电化学行为进行了研究.结果表明,LiV₃O₈在饱和Li₂SO₄水溶液中具有最好的电化学性能.以LiV₃O₈作为负极材料,LiNi_1/3Co_1/3Mn_1/3O₂作为正极材料,饱和Li₂SO₄水溶液作为电解液组成了水性锂离子电池,进行恒流充放电测试,结果表明,在0.5C(1C=300 mA·g^-1)的充放电倍率下,该水性锂离子电池的首次放电比容量为95.2 mAh·g^-1,循环100次后仍具有37.0 mAh·g^-1的放电比容量.     

拟薄水铝石/陶瓷胶态加工浆料的流变性能

用拟薄水铝石纳米胶粒分散微米二硼化钛形成固含量为60Wt%的稳定陶瓷浆料,实验考察了拟薄水铝石固含量、二硼化钛固含量、温度对浆料流变性、稳定性的影响,对纳米γ-AlOOH胶粒分散微米TiB2的机制进行了讨论.大小约20nm的γ-AlOOH颗粒相互网联,成为外加微米陶瓷颗粒的骨架.浆料粘度随二硼化钛固含量的增加而增大,温度升高有利于胶体中薄水铝胶团与二硼化钛颗粒的相互作用并促进分散.     

氢氧化钠水溶液体系中金属铬的电化学氧化过程

铬铁电氧化溶出技术是一种全新的制备铬酸钠的方法,具有反应条件温和、过程可控、工艺环保等优点,然而金属铬在NaOH水溶液中的电化学氧化过程尚不明确. 本文采用循环伏安法（CV）和阳极极化法（LSV）对金属铬在NaOH水溶液中的电化学氧化过程进行研究. 使用EDS、SEM、XRD和XPS对电解前后的金属铬表征,判断中间物的产生,使用紫外可见分光光度计验证电解液中生成了铬酸钠. 结果表明,金属铬和中间产物Cr(OH)₃可能依次发生电化学氧化直接生成Na₂CrO₄,阳极极化为金属铬的活化. 随着NaOH溶液浓度的增加,Cr(OH)₃和Na₂CrO₄的生成量在增加,金属铬电化学氧化制备铬酸钠的适宜条件为碱浓度≥ 2 mol·L^-1,阳极电势≥ 1.6 V（vs. SCE）.     

超细非晶态Fe-B和Co-B合金粒子的电化学行为

应用溶液还原法合成超细非晶态合金Fe B和Co B粒子,并研究这类材料的电化学行为.结果表明,尽管碱性溶液中单质硼和钴表现为电化学惰性,而单质铁的电化学活性很低,但Fe B和Co B却表现出特殊的电化学活性和放电容量.在100mA/g的恒流放电条件下,Co B和Fe B的比容量分别为1100mAh/g和1200mAh/g,远高于单质金属或硼元素预期的放电容量.这种超细非晶态合金(UAAP)电极的电化学活性可能来自于金属硼化物的电子性质,非晶态特征与纳米尺度的协同效应,前两因素使硼元素的活化和电子导电性得到改善,后者则增强了材料的反应活性和电化学利用率.     

AgNi合金作为直接硼氢化物燃料电池的阳极催化剂

采用机械球磨法制备银镍合金, 并将其用作直接硼氢化物燃料电池(DBFC)的阳极催化剂. XRD 和SEM实验表明, 这种催化剂为纳米粒子集聚的微米颗粒, 具有二元合金的典型结构特征. 电化学实验表明, AgNi合金不仅能够催化硼氢化物的直接电化学氧化, 而且可以抑制硼氢化物的化学水解. 当采用AgNi/C作为DBFC电池的阳极催化剂时,硼氢化钾的放电容量在3500 mAh·g-1以上, 对硼氢化物燃料的利用率可达90%以上.     

介孔结构磷酸钛正极材料的制备及其电化学性能

利用溶胶凝胶模板法结合煅烧的方法,通过外加和不加模板剂,分别制备出介孔结构和非介孔结构的磷酸钛正极材料,所得样品的结构和比表面积分别用X射线粉末衍射仪和低温N2吸脱附技术进行了表征,并对其电化学行为进行了研究.充放电测试结果表明,介孔结构的磷酸钛正极材料表现出优越的电化学性能,在500mA/g充放电条件下,首次放电容量高达81.9 mAh/g,而非介孔结构的磷酸钛正极材料的首次放电容量仅为11.4 mAh/g.     

水溶液中Ni-La-P合金的电沉积行为

为了开发含稀土的功能材料,我们研究了从水溶液中电沉积Ni-La-P合金工艺[1].刘淑兰等[2]报道了电沉积的Ni-La合金上的阴极析氢行为,但未见Ni-La合金电沉积行为的报道.本文采用动电位扫描法,研究了电沉积Ni-La-P合金过程中,镀液中的配体、H3PO3和Ni2 离子的作用.采用动电位扫描法测量合金电沉积时的阴极极化曲线.所用仪器有DHW型恒电位仪（延边电化学仪器厂）,YEW-TYPE-3086型X-Y函数记录仪（四川仪表四厂）.电极：阴极为1cm2铜片,阳极为5cm2Pt片,参比电极：饱和甘汞电极（SCE）.实验溶液广：NiCl2·6H2O25g/L,NH4Cl9g/L,L1-…     

混合金属氧化物阳极在海水中的电化学性能

采用热分解方法制备钛基混合金属氧化物阳极 ,用扫描电镜对阳极涂层显微形貌进行了分析 ,并通过实海模拟试验考察了混合金属氧化物阳极在海水阴极保护系统中的使用性能 .SEM分析结果表明 ,混合金属氧化物阳极涂层呈多孔多裂纹的显微结构 ,与其它阳极材料相比 ,此种阳极具有更大的活性表面积 .电化学试验结果表明 ,混合金属氧化物阳极在海水中具有良好的电化学稳定性和电化学活性 ;此外 ,混合金属氧化物阳极在海水中的消耗率很低 ,属于不溶性的阳极材料 ,作为外加电流阴极保护的辅助阳极具有广泛的应用前景     

有机盐PTO(KPD)2作为高性能锂离子电池正极材料的研究

采用溶剂热反应合成了一种新型的有机盐材料芘四酮-二均苯四甲酸二酰亚胺二钾盐PTO(KPD)₂. 该材料作为锂离子电池正极时, 表现出优异的循环和倍率性能. 研究结果表明, 在50 mA/g电流密度下, PTO(KPD)₂的实际放电比容量达到255.8 mA·h/g; 在500 mA/g电流密度下循环800次后, 容量保持率为81.1%. PTO(KPD)₂盐结构的形成提高了分子极性, 大大降低了其在电解液中的溶解度, 使得材料表现出优异的电化学性能.     

High voltage supercapacitors using hydrated graphene film in a neutral aqueous electrolyte

The potential stability windows of chemical converted graphene in different aqueous electrolyte solutions were investigated for the first time. Based on this result, a supercapacitor with a high voltage and long cycle-life was prepared with the hydrated graphene films in the neutral aqueous solution at the maximum voltage of 1.6 and even 1.8 V. The electrochemical performance of the obtained sample was systematically investigated by cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscopy. According to the cyclic voltammetry, hydrated graphene film can still retain rectangular shape at the high scan rate of 0.5 V/s in the neutral aqueous electrolyte. At a galvanostatic charge/discharge rate of 1 or 200 A/g, the specific capacitance of 202.3 or 138.1 F/g was delivered, respectively. Furthermore, the EIS results also confirm its fast neutral ion diffusion and high operating frequency of 9.34 Hz.     

A biomass carbon material with microtubule bundling and natural O-doping derived from goldenberry calyx and its electrochemical performance in supercapacitor

A promising biomass carbon material,manufactured by the carbonation of Physalis peruviana L.calyx at 700℃,is presented in this wo rk.Morphology characterization shows that the carbon material possesses long microtubule bundling and above 30%natural O-atom component on the surface.After KOH chemical etching,the materials maintain the oxygen content but exhibit more micropores and higher specific surface area up to 1732.6 m^2/g.Using as an electrode material for supercapacitor,the active carbon material exhibits high specific capacitance up to 339.7 F/g at 0.5 A/g in 3 mol/L KOH aqueous solution through three-electrode system.The active carbon material also exhibits excellent cycling stability(97%retention)by 10,000 cycles at 10 A/g.The outstanding electrochemical performances are attributing to the unique long microtubule bundling with much more pores and the abundant Oelement on the surface.This biomass carbon material with excellent electrochemical properties could be a useful material for multiple applications.     

Protein Templated Au-CuO Bimetallic Nanoclusters toward Neutral Glucose Sensing

In this study, the application of bovine serum albumin (BSA) as a carrier to glucose-sensitive materials for the detection of glucose was proposed. Au-CuO bimetallic nanoclusters (Au-CuO/BSA) were prepared using BSA as a template, the new sensing material (Au-CuO/BSA/MWCNTs) was synthesized by mixing with multi-walled carbon nanotubes (MWCNT) and applied to non-enzymatic electrochemical sensors to detect glucose stably and effectively under neutral condition. The scanning electron microscopy was used to investigate the morphology of the synthesized nanocomposite. The electrochemical properties of the sensor were studied by cyclic voltammetry. Glucose detection experiments show that Au-CuO/BSA/MWCNTs/Au electrode has good glucose detection ability, stability, accuracy, repeatability, and high selectivity in neutral environment. Unlike existing glucose-sensitive materials, due to the use of BSA, the composite material is firmly fixed to the electrode surface without a Nafion solution, which reduces the current blocking effect on the modified electrode. The composite materials can be effectively preserved for extremely long periods, higher than 80% activity is maintained at room temperature in a closed environment for 3 to 4 months, due to the special effects of BSA. In addition, the feasibility of using BSA in glucose-sensitive materials is confirmed.     

锂离子电池正极材料Na3V2（PO4）2F3的原位XRD及固体核磁共振研究

采用溶胶凝胶法制备Na3V2（PO4）2F3/C复合材料,该材料具有优异的电化学循环性能和倍率性能.利用电化学原位同步辐射X射线衍射（XRD）及魔角旋转固体核磁共振（MASSS-NMR）技术研究了Na3V2（PO4）2F3材料充放电过程中结构变化过程及Li/Na嵌入-脱出反应.研究结果表明,Na3V2（PO4）2F3的电极反应按嵌入-脱出反应机理进行,充放电过程中材料具有优异的结构稳定性.我们还发现Na3V2（PO4）2F3与电解液接触后与电解液中的Li＋发生部分交换反应形成LixNa3-xV2（PO4）2F3.在首次充电时,Li＋和结构中Na1位置的Na＋共同从晶格中脱出;而首次放电过程中,Na＋和Li＋共同嵌入到晶格中;充放电过程中发生的是Li＋和Na＋的共嵌入-脱出反应.     

以酚醛树脂为碳源原位合成富锂层状相/尖晶石/碳核壳结构正极材料及其电化学性能

通过酚醛树酯包覆和碳热反应在富锂正极材料表面原位构建碳和尖晶石双壳保护结构, 对这种核壳结构的正极材料进行了结构和形貌表征, 并研究了其电化学性能. 研究发现, 尖晶石相为材料提供了三维锂离子迁移通道, 碳包覆层显著提高了正极材料的电子电导率, 两种效应的共同作用极大降低了材料的电化学阻抗, 提升了材料的放电比容量, 这种多壳层结构正极材料还具有优异的倍率性能, 在5C倍率下放电比容量可达到135.1 mA·h/g.     

吡咯-(3,4-乙烯二氧噻吩)共聚物有序纳米阵列薄膜的制备及表征

采用阳极氧化铝(AAO)模板电化学沉积方法, 合成了1种新型吡咯-(3,4-乙烯二氧噻吩)(PE)共聚物纳米线阵列薄膜, 作为锂离子电池电极材料, 其表现出较高的比容量(1426.1 mA·h/g, 充放电电流密度为100 mA/g)和很好的循环稳定性(在充放电循环300圈之后, 比容量仍然保持在1400 mA·h/g以上). 这种多组分共聚物纳米线阵列有可能成为下一代长寿命、 高性能的锂离子电池电极材料而被广泛开发.     

锂离子电池纳米氧化镍负极的制备及应用

应用水热法制备纳米氧化镍,观察样品形貌及研究电极电化学性能.结果表明,在水热合成过程中加入表面活性剂十二烷基硫酸钠（SDS）,可形成疏松多孔、表面呈蜂窝状、颗粒均匀（100～200 nm）的纳米氧化镍.0.1 A/g电流密度下,该纳米NiO电极首周期放电比容量高达2385.7 mAh/g,100周期之后电极比容量仍然稳...     

Preparation and Pseudo-capacitance Performance of NiCo2O4 Nanosheets

Ternary nickel cobaltite(NiCo₂O₄), as a promising electrode material for supercapacitors, has attracted increasing attention for its excellent electrochemical properties. In this study, novel NiCo₂O₄ nanosheets were rationally designed and prepared using dealloying process, followed by an oxidation treatment. The as-prepared sample was characterized by microstructural and electrochemical techniques in view of its possible application in supercapacitors. The as-prepared sample exhibited high specific capacitance and excellent durability. The specific capacitance reached 663 F/g at 1 A/g and the rate capacitance high up to 73.6% when the current density increased from 1 A/g to 20 A/g. After 5000 cycles of galvanostatic charge-discharge durability test at 4 A/g, the capacity retention rate was 82.1%. The results indicate that versatile dealloying can be used to prepare robust electrode for supercapacitor application.     

Electrochemical supercapacitive properties of polypyrrole thin films: influence of the electropolymerization methods

A detailed study of the effects of different electropolymerization methods on the supercapacitive properties of polypyrrole (PPy) thin films deposited on carbon cloth is reported. Deposition mechanisms of PPy thin films through cyclic voltammetry (CV), potentiostatic (PS), and galvanostatic (GS) modes have been analyzed. The resulting PPy thin films have been characterized by X-ray photoelectron spectroscopy (XPS), SEM, and TEM. The electrochemical properties of PPy thin films were investigated by cyclic voltammetry and galvanostatic charge/discharge. The results showed that the different electrodeposition modes of synthesis significantly affect the supercapacitive properties of PPy thin films. Among different modes of electrodeposition, PPy synthesized by a potentiostatic mode exhibits maximum specific capacitance of 166 F/g with specific energy of 13 Wh/kg; this is attributed to equivalent proportions of the oxidized and neutral states of PPy. Thus, these results provide a useful orientation for the use of optimized electrodeposition modes for the growth of PPy thin films to be applied as electrode material in supercapacitors.