纳米b-Ni(OH)2的制备及其储锂性能

以Ni(NO₃)₂·6H₂O和NaOH为原料采用化学沉淀法制备了Ni(OH)₂电极材料。采用X射线衍射(XRD)和场发射扫描电子显微镜(FESEM)表征了样品的微观结构,结果表明该样品是具有片状纳米次级结构的β-Ni(OH)₂。采用循环伏安(CV)和电化学充放电测试研究了该β-Ni(OH)₂样品的储锂性能,结果发现该样品作为锂离子电池负极材料具有非常高的储锂活性,在50 mA·g^-1电流密度下其第3次循环放电比容量高于1550 mA·h·g^-1;样品电极中的碳含量对其循环性能和倍率性都有显著影响,通过交流阻抗(EIS)测试分析了样品电极中碳含量的作用机理。     

GO@MIL-101的制备及其对水中Cr（Ⅵ）的去除

通过水热法制备了掺杂氧化石墨烯（GO）的金属有机框架GO@MIL-101,并考察了GO掺杂量对GO@MIL-101形貌和性质的影响规律。GO的掺杂影响了MIL-101晶体的形成过程。随着GO掺杂量的增加,GO@MIL-101晶体的完整性降低、粒径减小,团聚现象越发显著。GO@MIL-101能够有效去除溶液中的Cr（Ⅵ）,该过程符合拟二级动力学方程。由Langmuir吸附等温线拟合得到的最大吸附量与GO掺杂量有关,在2%[相对于Cr（NO₃）₃·9H₂O质量]时达到最大,这与此时GO@MIL-101同时具有较大的比表面积和较大的孔体积有关。Cr（Ⅵ）的去除过程伴随着溶液中NO₃^-浓度的升高以及pH的下降,电荷平衡计量分析表明MIL-101和GO@MIL-101对Cr（Ⅵ）的去除机制相同,主要依靠MIL-101的离子交换作用,并且所去除的Cr（Ⅵ）以CrO₄^2-形式存在于固相中。     

Na0.44MnO2纳米棒/石墨烯正极的制备和电化学储锂性能

以KMnO₄、MnSO₄和NaOH为初始原料,利用水热软化学法制备Na_0.44MnO₂。XRD证实该材料具有S形孔道结构,TEM表征表明这是一种单晶纳米棒,可能有利于制备高性能正极材料。同时利用Hummers法制备石墨烯作为导电剂,通过搅拌法混合电极材料制备正极涂片。电化学测试研究显示随着的石墨烯添加量的增大,电池容量和倍率性能均得到提高。当石墨烯含量达到45%时,在0.1 A·g^-1电流密度下电池容量达到192.5 mAh·g^-1,在2.0 A·g^-1倍率电流密度下,其容量依然保持在123.4 mAh·g^-1,说明该电极材料有潜力应用于下一代高性能电池当中。     

纳米多孔NiO类空心微球负极材料的制备与储锂性能

以NiCl₂·6H₂O、尿素、葡萄糖为原料采用水热法制备了NiO前体,将前体在空气中烧结最终得到NiO电极活性材料。该NiO样品具有镂空结构的类空心球形貌,且由50~100 nm初级纳米颗粒构成。对该NiO样品作为锂离子电池负极材料的储锂性能进行了研究,结果发现赝电容效应对该材料储锂容量和倍率性能有重要贡献。因独特的空心纳米结构和赝电容效应,该材料表现出出色的电化学循环稳定性和优异的大倍率充放电性能。在500 mA·g^-1电流密度下,100圈充放电循环后放电比容量为650 mA·h·g^-1,容量保持率达86.6%;在10 A·g^-1的超高倍率下,其稳定放电比容量仍高达432 mA·h·g^-1。     

Facile synthesis of porous hollow Co3O4 microfibers derived-from metal-organic frameworks as an advanced anode for lithium ion batteries

Co₃O₄, as a promising anode material for the next generation lithium ion batteries to replace graphite, displays high theoretical capacity (890 mAh g⁻¹) and excellent electrochemical properties. However, the drawbacks of its poor cycle performance caused by large volume changes during charge-discharge process and low initial coulombic efficiency due to large irreversible reaction impede its practical application. Herein, we have developed a porous hollow Co₃O₄ microfiber with 500 nm diameter and 60 nm wall thickness synthesized via a facile chemical precipitation method with subsequent thermal decomposition. As an advanced anode for lithium ion batteries, the porous hollow Co₃O₄ microfibers deliver an obviously enhanced electrochemical property in terms of lithium storage capacity (1177.4 mA h g⁻¹ at 100 mA g⁻¹), initial coulombic efficiency (82.9%) and cycle performance (76.6% capacity retention at 200th cycle). This enhancement could be attributed to the well-designed microstructure of porous hollow Co₃O₄ microfibers, which could increase the contact surface area between electrolyte and active materials and accommodate the volume variations via additional void space during cycling.     

Crystal chemistry modification of lithium nickel cobalt oxide cathodes for lithium ion rechargeable batteries

As a cathode material for lithium ion rechargeable batteries, LiNi_0.8Co_0.2O₂ (LNCO) is one of the most attractive candidates for high power electronic devices. In the present work, we have synthesized LNCO powder by solid-state route. The discharge capacity and the capacity retention of LNCO cathode are found to be 100 mAh g⁻¹ and 63%, respectively. Molybdenum doping, replacing parts of cobalt ion in LNCO lattice increases the discharge capacity (157 mAh g⁻¹) and improve its capacity retention characteristics. Through X-ray Rietveld analyses, we have found that Mo doping increases the inter-slab spacing between the (Co,Ni)O₂ octahedral layers which provides easier Li¹⁺ intercalation leading to improved electrochemical properties in the modified cathode.     

Effects of substrate bias voltage on adhesion of DC magnetron-sputtered copper films on E24 carbon steel: investigations by Auger electron spectroscopy

The adhesion strength of copper thin films on E24 carbon steel substrates was studied using the scratch test via the critical load. Coatings were deposited by a DC magnetron sputtering system. All substrates were mechanically polished; some of them were directly coated and others were ion-etched by argon ions prior to deposition process. The effects of substrate negative bias voltage during the film growth were investigated. Experimental results showed that the critical load depended on the bias voltage and that the higher bias voltage, the better adhesion. It was also observed that the deposition rate of deposited films gradually decreased with the increase of the substrate bias voltage. Furthermore, the working pressure during the substrate ion bombardment etching greatly affected the critical load. Scanning electron microscopy was used to observe the scratch tracks to accurately evaluate the critical load. Substrate surface profiles obtained by a mechanical profilometer showed that the critical load increased with the increase of the surface roughness. The analysis by Auger electron spectroscopy revealed that the interface, in case of an unbiased substrate, was relatively narrow and abrupt. However, in case of a bias voltage application, the interface was wider and more diffuse. These results suggest that the mechanisms involved in critical load enhancement are due firstly to the substrate surface roughness and the substrate temperature generated by the ion bombardment, secondly to the physical mixing in the interfacial domain and the densification of the deposited material created by the bias voltage.     

用732强酸性阳离子交换树脂去除铬酸盐钝化液中的锌离子

对732强酸性阳离子交换树脂再生铬酸盐钝化液进行了探索。研究了交换处理时间、溶液初始pH、Zn(II)初始浓度及树脂用量对树脂吸附的影响,并考察了树脂的脱附和再生性能。结果表明,该树脂对Zn(II)的吸附速率快,30 min达到吸附平衡,最佳吸附pH为3~6。用树脂再生钝化液不会对Cr(VI)浓度产生影响,能达到"去锌保铬"的目的。该树脂对Zn(II)的吸附符合Langmuir吸附等温模型,为单分子层吸附,具有吸附饱和性,饱和吸附量约为85.6 mg/g。     

卤水中添加水氯镁石对硫酸根析出的影响研究

盐田用含硫酸根卤水制取的光卤石含有硫酸盐杂盐,作者通过在卤水蒸发过程中不同阶段添加水氯镁石,考察硫酸根析出的影响研究.结果表明：75℃蒸发条件下,卤水在光卤石饱和点添加m（水氯镁石）∶m（原始卤水）=1∶18.75～1∶20时,可以减少硫酸盐析出,得到w（SO42-）=1.28％的纯度较高的光卤石.     

矿渣掺量对混凝土氯离子结合能力的影响

用等温吸附法测定了混凝土在系列氯化钠(NaCl)溶液中的平衡氯离子(Cl-)浓度,计算了矿渣混凝土对Cl-的总结合能力、物理结合能力和化学结合能力,研究了矿渣掺量对混凝土Cl-结合能力影响的规律.结果表明:在固定水胶比和胶凝材料用量的情况下,随矿渣掺量的增加,混凝土对Cl-的总结合能力和化学结合能力的变化趋势是先升后降;混凝土对Cl-的物理结合能力的影响不大.混凝土具有最大Cl-结合能力时的矿渣掺量(质量分数)为40%.