磷酸改性天然石墨负极材料的设计、制备及性能研究

利用石墨层间化合物技术处理天然石墨,使磷酸进入到石墨层表面,并在石墨表面包覆一层有机胺中间体,然后在惰性气氛下进行高温处理。研究发现,所得材料在保持石墨原始结构不被破坏的情况下,增大了石墨的层间距,为锂离子的嵌入和脱出拓宽了通道,也为材料在充放电过程中预留了膨胀体积。将这种材料用于锂离子电池负极材料、电化学性能测试表明或改性材料中可具有更小的不可逆容量和更高的充放电效率,并且在大电流充放电情况下,倍率性能得到了提升。     

复合插层剂制备低温可膨胀石墨研究

以HNO3/H3BO3/KMnO4为氧化插层体系制备低温可膨胀石墨,从HNO3用量、H3BO3用量、高锰酸钾用量、反应温度和反应时间等5个方面讨论了制备低温可膨胀石墨的最佳条件和物料配比。结果表明:制备低温可膨胀石墨的最佳反应温度为45℃,反应时间60min,石墨、HNO3、H3BO3、高锰酸钾的最佳质量比为3∶8∶1∶0.4,由此方法制得的石墨膨胀容积可达到228mL/g。该研究未使用任何含硫的试剂,因而制备的可膨胀石墨不含硫。     

阻燃木材的燃烧特性分析（二）

根据木材阻燃机理,以磷-氮体系阻燃剂为主进行复配,获得3组配方（质量比）：三聚氰胺∶磷酸∶硼酸=2∶2∶3;聚磷酸铵∶双氰胺=2∶1;尿素∶双氰胺∶磷酸=1∶3∶4。每组配方分别配制浓度为5%,10%,15%的阻燃液,采用浸渍法在恒温80℃下,浸渍24 h处理白杨木材试样。利用锥形量热仪在热辐射功率为50 kW/m2的条件下,对阻燃处理后的木材试样以及空白试样进行燃烧特性分析。实验结果表明,三聚氰胺、磷酸、硼酸组成的配方在增强木材试样的耐火性、抑制试样产烟量和一氧化碳生成率方面效果显著;聚磷酸铵APP、双氰胺组成的配方在控制木材试样燃烧速度和降低总热释放量方面效果显著;尿素、双氰胺、磷酸组成的配方在提高载药量、降低热释放速率、延长点燃时间、抑制二氧化碳生成率方面效果显著;3组配方在降低木材试样的质量损失率和有效燃烧热方面效果相近。综合各项分析结果,确定尿素、双氰胺、磷酸按1∶3∶4的比例（质量比）配制浓度为15%的阻燃液为最佳配方。     

梭形Fe_5(PO_4)_4(OH)_3·2H_2O的一步水热法制备及生长机理研究

采用可控的一步水热法制备出了具有对称棱边的梭形Fe5(PO4)4(OH)3·2H2O产物。利用X-射线衍射、场发射扫描电子显微镜、透射电子显微镜等手段对产物进行了表征,发现产物的生长机理符合Ostwald熟化过程。研究表明:在180℃下反应96h后会得到多臂形貌的纯相Fe5(PO4)4(OH)3·2H2O产物,且在低温下更容易获得纯相的Fe5(PO4)4(OH)3·2H2O梭形产物。此外研究发现,产物在500℃热处理后具有较好的形貌和尺寸上的热稳定性。     

纳米硼磷酸盐NaZn(H2O)2[BP2O8]·H2O的低温离子热合成与表征

硼磷酸盐是一类包含硼氧基团(BO4、BO3)和磷氧基团(PO4)的新化合物,目前所报道的硼磷酸盐几乎都在高温高压条件下合成。近几年离子法用于硼磷酸盐的合成逐渐受到关注。基于离子液体的特点,尝试了常压低温下硼磷酸盐的合成,并成功地应用于以离子液体[Emim]Br为溶剂,常压、80～100℃条件下合成纳米硼磷酸盐Zn(H2O)2[BP2O8]·H2O。产物通过X–射线粉末衍射进行了物相表征,并用扫描电镜(SEM)观察其形貌。结果表明,Zn(H2O)2[BP2O8]·H2O可在80℃下,40min内快速形成,通过改变反应时间、温度和陈化时间,研究了其对硼磷酸盐纳米晶体形成及形貌的影响。     

以粉煤灰和碎玻璃为主要原料研制泡沫玻璃

对发泡剂种类与掺量、发泡温度和时间、烧结温度和时间以及稳定剂掺量对泡沫玻璃质量的影响进行讨论,并得到制备粉煤灰泡沫玻璃的最佳工艺参数。对比了添加黏土与不添加黏土的粉煤灰泡沫玻璃的性质,分析了黏土对制作粉煤灰泡沫玻璃的影响。结果表明,当主要原料为37%的粉煤灰、58%的碎玻璃和5%的黏土时,添加7.5%的碳酸钠和2.5%的碳粉作为发泡剂,1.5%的磷酸钠作稳定剂,1.5%的硼酸作助熔剂,830℃下发泡60min,930℃下烧结60min,得到的泡沫玻璃质量最好。黏土有增大泡沫玻璃强度的作用。     

Multiple structure graphite stabilized stearic acid as composite phase change materials for thermal energy storage

This paper used 3 types of graphite with different physical structures as the porous matrix to prepare composite phase change materials (PCMs), and investigated their photo-thermal conversion performance and application in battery thermal management. Multiple structure graphite minerals, including microcrystalline graphite (MG), scale graphite (SG), and expanded graphite (EG) were used as porous matrix, while stearic acid (SA) acts as the phase change material. The vacuum impregnation method was applied to prepare SA/MG, SA/SG, SA/EG, and SA/MG1, and SA/EG1was/were prepared by the ethyl alcohol method. Results show that the thermal conductivities of all composite phase change materials were 10.82 to 22.06 times higher than that of the pure SA. Thermogravimetric (TG) analysis showed that the loadages of SA were 43.61%, 18.74%, and 92.66% for SA/MG, SA/SG, and SA/EG respectively. The load rates of SA were 18.98% and 18.88% for SA/MG1 and SA/EG1, respectively. For the 3 types of graphite materials of different dimensions, the BET (Brunauer, Emmett, and Teller) surface area determines the maximum load of SA. The Fourier-transform infrared (FTIR) and X-ray diffraction (XRD) results indicated that there was good compatibility between the SA and the supports. The SA/EG1 has better thermophysical properties in heat energy storage and release process. The thermal infrared images show that SA/EG1 has higher sensitivity to the temperature changes. SA/EG1 has better photo-heat conversion performance than SA/SG and SA/MG1 attributed to the multilayer structure of EG. SA/EG has better thermal management performance in the Li-ion batteries discharge process.     

磷酸－铵脱水缩聚动力学

本文研究了化学纯ＮＨ４Ｈ２ＰＯ４、农用磷铵及在二者中添加ＺｎＳＯ４·７Ｈ２Ｏ的脱水缩聚动力学，并用纸色谱法分析出了缩聚产物中聚磷酸盐的组成。实验结果表明，农用磷铵的脱水缩聚较纯磷铵的脱水缩聚容易进行。     

石墨与GIC电极在硫酸溶液中的循环伏安特性

为深入认识石墨与石墨层间化合物在Ｈ２ＳＯ４溶液中电化学嵌入／脱嵌行为及有关影响因素,探讨其作为二次电池电极材料的可能性,进行了循环伏安测量与充、放电实验。结果表明,Ｈ２ＳＯ４的浓度对两咱电极的嵌入／脱嵌容量、极化大小以及过氧化物的生成等均有较大的影响;     

ANA型硼磷酸锌分子筛的微波合成

采用微波合成法,以ZnCl2·6H2O、(NH4)2HPO4、H3BO3为反应原料,乙二醇作为助溶剂,功率400W,200℃反应2h合成出一种具有ANA拓扑结构的硼磷酸锌分子筛(NH4)16[Zn16B8P24O96],系统研究了晶种和加水量等因素对产物的影响。采用XRD、SEM和元素分析等分析方法对产物进行表征。结果表明,晶种可以控制晶体尺寸的大小,微量水的存在可以提高体系的分散性。     

Nanoscale Properties of Boric Acid

Nanoseale properties of boric acid were studied by using atomic force microscopy (AFM) and nanomechanical testing system. XPS was used to research on the transform behaviors of H3BO3 at different temperatures.The crystal structure, surface morphology, and mechanical properties of H2BO3 were described. The results show that H2BO3 has layered structure, and can be transformed to boron oxide at high temperature. In addition there are a lot of defects in H2BO3 crystal.     

Mild oxidation treatment of graphite anode for Li-ion batteries

1　INTRODUCTIONNumerous carbonaceous materials have beeninvestigated as anodes of lithium ion batteries dur ing the past several years[1 4]. Graphite is an at tractive material for anodes of lithium ion batteriesdue to its high reversible capacity (372 mA·h/g intheory), low and flat discharge potential (0.1 0.2 Vvs. Li)[5 8]. However, there are still some prob lems for the graphite in the application with respectto a low practically available capacity, and a largeir…     

碳包覆石墨作为锂离子电池负极材料的研究

将天然石墨(NG)用浓HNO3氧化处理后,在其表面包覆柠檬酸,在惰性气体气氛下700℃处理18h,制得了包覆改性石墨.采用XRD及电化学测试等手段对材料进行了结构表征和性能测试.考察了不同包覆比例对材料充放电性能的影响.XRD结果表明包覆改性对石墨的结构并没有明显的影响.充放电测试表明,与天然石墨相比,包覆改性石墨具有更好的电化学性能,其中又以石墨与柠檬酸质量比为2∶1时性能最好,其首次放电容量为345.1 mA h g1,经20次循环后容量仍保持在305 mA h g1以上,容量衰减率仅为11.01%.     

微波消解-石墨炉原子吸收光谱法测定植物样品中痕量钒

用微波消解-石墨炉原子吸收光谱法测定植物样品中微量钒。研究了不同微波消化体系对植物钒测定结果的影响,确定了微波消解样品和石墨炉原子吸收测定钒的最佳条件。结果表明,采用四段微波消解方式,以HNO3-H2O2为消解液、EDTA为基体改进剂,在5％的HNO3介质中进行钒测定可获得满意的结果。方法的检出限为0．72μg／L,线性范围0～300μg／L,相关系数R=0．9988。该法简便快速,具有高灵敏度和准确度,用于蔬菜样中钒的测定,回收率在98．4％-103．8％,标准试样结果相对误差小于3％。     

Modification of natural graphite using pitch through dynamical melt-carbonization

The graphite was modified using pitch through dynamical melt-carbonization, and the effects of modification temperature and the amount of pitch on the characteristics of graphite were investigated. The structure and characteristics of the graphite were determined by X-ray diffractometry(XRD), scanning electron microscopy(SEM), particle size analysis and electrochemical measurements. The results show that the modified graphite has a disordered carbon/graphite composite structure, larger average particle diameter, greater tap density, and better electrochemical characteristics than the untreated graphite. The sample coated with 10% pitch dynamical melt-carbonized at 400 ℃ for 3 h and heat-treated at 850 ℃ for 2 h has better electrochemical performances with a reversible capacity of 360.5 mA·h/g, a irreversible capacity of 41.0 mA·h/g, and an initial coulombic efficiency of 89.8% compared with natural graphite and disordered carbon. The cycling stability of the Li/C cell with modified graphite as anodes is improved, and its capacity retention ratio at the 30th cycle is up to 94.37%.     

Preparation and electrochemical properties of Co3O4/graphite composites as anodes of lithium ion batteries

Co3O4/graphite composites were synthesized by precipitation of cobalt oxalate on the surface of graphite and pyrolysis of the precipitate, and the effects of graphite content and calcination temperature on the electrochemical properties of the composites were investigated. The samples were characterized by thermogravimetry and differential thermal analysis (TG/DTA), X-ray diffractometry (XRD), scanning electron microscopy (SEM), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and charge/discharge measurements. With increasing the graphite content, the reversible capacity of the Co3O4/graphite composites decreases, while cycling stability improves dramatically, and the addition of graphite obviously decreases the average potential of lithium intercalation/deintercalation. The reversible capacity of the composites with 50% graphite rises from 583 to 725 mAh/g as the calcination temperature increases from 300 to 500 ℃, and the Co3O4/graphite composites synthesized at 400 ℃ show the best cycling stability without capacity loss in the initial 20 cycles. The CV profile of the composite presents two couples of redox peaks, corresponding to the lithium intercalaction/deintercalation for graphite and Co3O4, respectively. EIS studies indicate that the electrochemical impedance decreases with increasing the graphite content.     

Preparation of QTi4.3-4Graghite Composite by Semi-solid Casting Technology

The electromagnetic-mechanical stirring technology was employed for preparing QTi4.3-4 graghite composite slurry,and QTi4.3-4 graghite composite with uniform distribution of graphite particles was prepared uring the semi-solid casting technology successfully.The structure of this QTi4.3-4graphite composite was studied and the condition for uniform distribution of graphite particles was got.The experimental results show that there exists a linear relationship between the solid fraction and the stirring temperature of QTi4.3-4graphite slurry.With the decreasing of stirring temperature,the solid fraction of QTi4.3-4 graghite slurry increases constantly.In casting,with the increasing of solid fraction of QTi4.3-4 graphite slurry.the agglomeration of graphite particles is removed gradually.When the solid fraction is higher than 40%,graphite particles can distribute evenly in QTi4.3-4 graghite composite.     

膨胀石墨对柴油吸附性的实验研究

水体油污染是当今迫切需要解决的环境问题之一，本文探讨了各种膨胀石墨对柴油的吸附性能。结果表明，膨胀石墨对柴油具有较大吸附量，膨胀容积越大吸附量越大，采取静态吸附和动态吸附都可有效清除水面漂浮柴油，动态吸附可大大降低水中乳化柴油浓度。     

石墨漂浮对球铁机械性能的影响

研究了石墨漂浮对球铁机械性能的影响规律．结果表明：石墨漂浮的出现使球铁的抗拉强度降为非漂浮区的８０％;延伸率为非漂浮区的７５％;断面收缩率为非漂浮区的６０％;冲击韧性平均降低为非漂浮区的２０％;残余屈服强度略有降低,对布氏硬度影响不大．石墨漂浮对球铁机械性能的影响不取决于铸件漂浮层深度,而取决于漂浮的有无．     

Preparation and electrochemical properties of Co3O4/graphite composites as anodes of lithium ion batteries

Co₃O₄/graphite composites were synthesized by precipitation of cobalt oxalate on the surface of graphite and pyrolysis of the precipitate, and the effects of graphite content and calcination temperature on the electrochemical properties of the composites were investigated. The samples were characterized by thermogravimetry and differential thermal analysis (TG/DTA), X-ray diffractometry (XRD), scanning electron microscopy (SEM), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and charge/discharge measurements. With increasing the graphite content, the reversible capacity of the Co₃O₄/graphite composites decreases, while cycling stability improves dramatically, and the addition of graphite obviously decreases the average potential of lithium intercalation/deintercalation. The reversible capacity of the composites with 50% graphite rises from 583 to 725 mA·h/g as the calcination temperature increases from 300 to 500 °C, and the Co₃O₄/graphite composites synthesized at 400 °C show the best cycling stability without capacity loss in the initial 20 cycles. The CV profile of the composite presents two couples of redox peaks, corresponding to the lithium intercalaction/deintercalation for graphite and Co₃O₄, respectively. EIS studies indicate that the electrochemical impedance decreases with increasing the graphite content.