Synthesis and characterization of Mg3(PO4)2-coated Li1.05Ni1/3Mn1/3Co1/3O2 cathode material for Li-ion battery

Mg₃(PO₄)₂-coated Li_1.05Ni_1/3Mn_1/3Co_1/3O₂ cathode materials were synthesized via co-precipitation method. The morphology, structure, electrochemical performance and thermal stability were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), cyclic voltammetry(CV), electrochemical impedance spectroscopy(EIS), charge/discharge cycling and differential scanning calorimeter (DSC). SEM analysis shows that Mg₃(PO₄)₂-coating changes the morphologies of their particles and increases the grains size. XRD and CV results show that Mg₃(PO₄)₂-coating powder is homogeneous and has better layered structure than the bare one. Mg₃(PO₄)₂-coating improved high rate discharge capacity and cycle-life performance. The reason why the cycling performance of Mg₃(PO₄)₂-coated sample at 55 °C was better than that of room temperature was the increasing of lithium-ion diffusion rate and charge transfer rate with temperature rising. Mg₃(PO₄)₂-coating improved the cathode thermal stability, and the result was consistent with thermal abuse tests using Li-ion cells: the Mg₃(PO₄)₂ coated Li_1.05Ni_1/3Mn_1/3Co_1/3O₂ cathode did not exhibit thermal runaway with smoke and explosion, in contrast to the cells containing the bare Li_1.05Ni_1/3Mn_1/3Co_1/3O₂. Funded by the National Natural Science Foundation of China (No. 20273047)     

Comparative experiment on layered Li（Ni1/3Co1/3Mn1/3）O2 as the alternative material for LiCoO2

This work was financially supported by the National Natural Science Foundation of China （No.50472093）.     

Modification of LiCo1/3Ni1/3Mn1/3O2 cathode material by CeO2-coating

LiCo_1/3Ni_1/3Mn_1/3O₂ was coated by a layer of 1.0 wt% CeO₂ via sol-gel method. The bared and coated LiMn_1/3Co_1/3Ni_1/3O₂ was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), cyclic voltammogram (CV) and galvanotactic charge-discharge test. The results show that the coating layer has no effect on the crystal structure, only coating on the surface; the 1.0 wt% CeO₂-coated LiCo_1/3Ni_1/3Mn_1/3O₂ exhibits better discharge capacity and cycling performance than the bared LiCo_1/3Ni_1/3Mn_1/3O₂. The discharge capacity of 1.0 wt% CeO₂-coated cathode is 182.5 mAh·g⁻¹ at a current density of 20 mA·g⁻¹, in contrast to 165.8 mAh·g⁻¹of the bared sample. The discharge capacity retention of 1.0 wt% CeO₂-coated sample after 12 cycles reaches 93.2%, in comparison with 86.6% of the bared sample. CV results show that the CeO₂ coating could suppress phase transitions and prevent the surface of cathode material from direct contact with the electrolyte, thus enhance the electrochemical performance of the coated material.     

Characteristics of LiCoO2, LiMn2O4 and LiNi0.45Co0.1Mn0.45O2 as cathodes of lithium ion batteries

LiNi_0.45Co_0.10Mn_0.45O₂ was synthesized from Li₂CO₃ and a triple oxide of nickel, cobalt and manganese at 950 °C in air. The structures and characteristics of LiNi_0.45Co_0.10Mn_0.45O₂, LiCoO₂ and LiMn₂O₄ were investigated by XRD, SEM and electrochemical measurements. The results show that LiNi_0.45Co_0.10Mn_0.45O₂ has a layered structure with hexagonal lattice. The commercial LiCoO₂ has sphere-like appearance and smooth surfaces, while the LiMn₂O₄ and LiNi_0.45Co_0.10Mn_0.45O₂ consist of cornered and uneven particles. LiNi_0.45Co_0.10Mn_0.45O₂ has a large discharge capacity of 140.9 mA · h/g in practical lithium ion battery, which is 33.4% and 2.8% above that of LiMn₂O₄ and LiCoO₂, respectively. LiCoO₂ and LiMn₂O₄ have higher discharge voltage and better rate-capability than LiNi_0.45Co_0.10Mn_0.45O₂. All the three cathodes have excellent cycling performance with capacity retention of above 89.3% at the 250th cycle. Batteries with LiMn₂O₄ or LiNi_0.45Co_0.10Mn_0.45O₂ cathodes show better safety performance under abusive conditions than those with LiCoO₂ cathodes. Foundation item: Project(50302016) supported by the National Natural Science Foundation of China; Project(2005037698) supported by the Postdoctoral Science Foundation of China     

Al_2O_3包覆对富锂锰基正极材料Li_(1.2)Mn_(0.54)Co_(0.13)Ni_(0.13)O_2的电化学性能影响

采用水热法合成富锂三元正极材料,探究了最佳包覆比例下Al_2O_3包覆对材料的电化学性能影响.采用扫描电镜(SEM)和X射线衍射仪(XRD)表征了富锂三元正极材料的表面形貌和结构,通过循环伏安(CV)、交流阻抗(EIS)技术分析了材料电化学性的影响因素.结果表明,通过异丙醇铝水解制得了氧化铝包覆层,提高了材料的比容量,稳定了材料的结构.     

基于双金属MOFs 制备Co3O4/In2O3 复合物及其气敏性能的研究

以硝酸铟(In(NO₃)₃·xH₂O)、对苯二甲酸(H₂BDC)、六水合硝酸钴(Co(NO₃)· 6H₂O) 为原料, 首先采用一锅油浴法合成了含有Co²⁺ 的铟基金属有机框架材料(MOFs) Co²⁺/CPP-3(In) 材料, 然后在450 ℃ 下焙烧制备Co₃O₄/In₂O₃ 复合物气敏材料, 将Co₃O₄/In₂O₃ 复合物的粉体制作成传感器, 并对其气敏性能进行研究。利用扫描电子显微镜和X 射线衍射仪(XRD) 对双金属MOFs Co²⁺/CPP-3(In) 材料和Co₃O₄/In₂O₃ 复合物进行表征, 采用静态配气法测试其气敏性能。结果表明, Co₃O₄/In₂O₃(n_Co : n_In = 0.4 : 1) 样品的形貌保留了其MOFs 前驱体的棒状结构, 棱柱形框架更为突出, 表面呈凹陷状, 棒体中间粗两边细, 六角截面和棒体均布满了孔洞。结合EDX 和XRD 表征结果, Co²⁺/CPP-3(In) MOFs 前驱体完全转化成Co₃O₄/In₂O₃ 复合物; Co₃O₄/In₂O₃(n_Co : n_In = 0.4 : 1) 复合物在 70 ℃ 下对5×10^-6 H₂S 的气敏性能最优, 响应值达到153, 是同条件下纯备In₂O₃对H₂S 响应值的5 倍, 并且有较好的重复性、选择性和稳定性。     

Na+掺杂对LiNi1/3Co1/3Mn1/3O2结构和电化学性质的影响

采用高温固相法成功制备了不同Na+掺杂浓度的Li_1-xNa_xNi_1/3Co_1/3Mn_1/3O₂锂离子电池正极材料,探究了Na元素掺杂对层状氧化物正极材料结构以及电化学性能的影响。通过X射线粉末衍射仪和扫描电子显微镜表征了材料的结构和形貌,结果表明,当x≤0.3时,样品不会出现其它杂相;当x＞0.3时,样品中会出现NaNi_1/3Co_1/3Mn_1/3O₂的杂相。同时随着掺杂浓度的增加,样品的阳离子混排度逐渐增加。电化学性能结果表明,少量Na+的掺入可以提高LiNi_1/3Co_1/3Mn_1/3O₂在0.2C,0.5C下的放电比容量并增强其循环稳定性,但会损坏材料的倍率性能。     

锌对Li（Ni_（1/3）Co_（1/3）Mn_（1/3））O_2电极首次脱锂过程电化学性能的影响

共沉积法制备不同含锌量的锂离子电池正极材料Li（Ni1/3Co1/3Mn1/3）O2.采用交流阻抗谱分析该正极材料在首次脱锂过程中的电化学特性以及锌对电极阻抗和锂离子扩散系数的影响.电极阻抗图谱分析结果表明：3.7～4.4V为电极发生电化学反应的电位区间;锌减小了电极材料的SEI膜阻抗和电荷转移阻抗;少量固溶锌提高了锂离子在材料固相中的扩散能力.     

Corrosion resistance of plasma sprayed NiCrAl+(ZrO2+Y2O3) thermal barrier coating on 18-8 steel surface

The corrosion resistance of NiCrAl+(ZrO₂+Y₂O₃) thermal barrier coating, formed with the plasma spraying technique, on the 18 - 8 steel surface was investigated. The phase structure and morphology of the coating were analyzed by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM). The electrochemical corrosion behavior of the coating in 1.0 mol/L H₂SO₄ solution was studied by using electrochemical measurement methods. The results show that the gradient plasma spraying coating is composed of the NiCrAlY coating and the (ZrO₂+Y₂O₃) top coating, and the coating thickness is 360 μm. The microhardness of coating reaches 1 100 HV. The corrosion resistance of the plasma sprayed coating of the 18 - 8 steel surface is about 5 times as great as that of the original pattern. The corrosion resistance of the coating is enhanced notably. Foundation item: Project (5040202140) supported by Scientific Research Common Program of Beijing Municipal Commission of Education     

N掺杂Co3O4纳米片的制备以及活化过一硫酸盐的性能研究

采用牺牲模板法合成N掺杂Co₃O₄纳米片（N-Co NS）,通过透射电子显微镜（TEM）、原子力显微镜（AFM）和光电子能谱（XPS）对制备材料的形貌结构、化学组成进行分析,并通过催化活化过一硫酸盐（PMS）降解水中双酚A （BPA）来探究催化剂的催化性能.实验结果表明与Co₃O₄纳米颗粒（Co NP）、Co₃O₄纳米片（Co NS）相比,N-Co NS表现出了较高的催化性能.在PMS浓度为2 mmol·L^-1、BPA初始质量浓度为50 mg·L^-1的反应条件下,N-Co NS在10 min内完全降解水中的BPA,表明N掺杂和二维纳米片结构有利于催化剂性能的提升.通过pH及离子影响实验证实N-Co NS在复杂水化学环境中仍具有较高的活性.此外结合自由基捕获实验和电子顺磁共振（EPR）测试证实反应体系中产生了高氧化活性的羟基自由基和硫酸根自由基.     

Luminescent properties of BaO-La2O3-B2O3 glasses with dopant

The luminescent properties of glasses synthesized in air atmosphere by conventional high temperature process were stud{ed. The emissions spectra of Eu^2 and Eu^3 were observed in BaO-La2O3-B2O3-Eu2O3 glasses.The results show that the broad emission peaks at 430 nm correspond to 5d→4f emission transition of Eu^2 , the sharp emission peaks at 592, 616, 650 and 250 nm correspond to 5^D0→1Fj(j=1--4) emission transition of Eu^3 ,respectively, which indicates that the BaO-La2O3a-B2O3-Eu2O3 glass can convert ultraviolet and green omponents of sunlight into blue and red light so as to increase the intensity of blue and red light, respectively. The luminescent in--tensity of Eu^2 increases with increasing the molar ratio of Tb^3 in BaO-La2O3-B2O3-Eu2O3a-Tb4O3 glasses, whereas the luminescent intensity of Eua^3 decreases. So the luminescent intensity of Eu(Ⅲ,Ⅱ) is influenced by Tb^3 .These phenomena can be explained by electron transfer mechanism; Eu^3 (4f6) Tb^3 (4f^8)→Eu^2 (4f′) Tb^4 (4f′). Taking advantage of the luminescent properties of BaO-La2O3-B2O3-Eu2O3 glasses, light-conversion glass for agriculture can be produced.     

Coating of LiNi1/3Mn1/3Co1/3O2 cathode materials with alumina by solid state reaction at room temperature

Alumina coated LiNi1/3Mn1/3Co1/3O2 particles were obtained by a simple method of solid state reaction at room temperature. The reaction mechanism of solid state reaction at room temperature was investigated. The structure and morphology of the coating materials were investigated by XRD, SEM and TEM. The electrochemical performances of uncoated and Al2O3-coated LiNi1/3Co1/3Mn1/3O2 cathode materials were studied within a voltage window of 3.00-4.35 V at current density of 30 mA/g. SEM, TEM and EDS analytical results indicate that the surface of LiNi1/3Mn1/3Co1/3O2 particles is coated with very fine Al2O3 composite, which leads to the improved cycle ability though a slight decrease in the first discharge capacity is observed. It is proposed that surface treatment by solid state reaction at room temperature is a simple and effective method to improve the cycle performance of LiNi1/3Co1/3Mn1/3O2 particles.     

Effect of Fe2O3 on the Formation of Micro Glass Beads under Air Staged Combustion

空气分级燃烧条件下Fe2O3对玻璃微珠生成的影响

张远军,王大凯,程星星,王志强*

（山东大学能源与动力工程学院,济南 250061）

摘要：

在空气分级燃烧条件下,研究了Fe2O3对玻璃微珠（MGBs）生成的影响。实验温度为1450℃,以鹤岗烟煤作为实验对象。利用X射线衍射仪（XRD）、灰熔融测试仪、粘度公式和扫描电镜（SEM）对飞灰进行了分析。使用Nano-Measurer 1.2软件测量了玻璃微珠的直径。结果表明,随着鹤岗煤中Fe2O3含量的增加,飞灰中的玻璃相含量先增加后降低。当Fe2O3含量为15%时,玻璃相含量达到最高,为51.26%。灰熔点先降低后升高,而粘度逐渐降低,颗粒逐渐呈球形。随着Fe2O3含量的增加,粒径小于10μm的玻璃微珠比例逐渐增加。从以上结果可以得出结论,Fe2O3的加入有利于玻璃微珠的生成和粒径的减小。

关键词：玻璃微珠;飞灰;Fe2O3;空气分级燃烧

     

Pressureless sintered 3Y-TZP/20%Al2O3 composite ceramic

Nanometer 3Y-TZP/20%Al₂O₃ (mass fraction) composite powders prepared by the chemical coprecipitation method were pressureless sintered at 1550 °C for 2 h. Effects of calcining temperatures at 800 °C, 1 000 °C, and 1 200 °C on phase structure, relative density, and Vicker’s hardness of the sintered bodies were studied. The results show that 1 000 °C was the optimal calcining temperature, and the powder calcined was composed of tetragonal zirconia with the Scherrer crystalline size of 6.3nm. The relative density was up to 98.5% under pressureless sintering, and the sintered body was t-ZrO₂ (without m-ZrO₂)+α-Al₂O₃ with the average size of 0.4 μm. Foundation item: State Key Laboratory for Powder Metallurgy(No.9706-36) Biography of the first author: YIN Bang-yao, born in 1966, majoring in advanced ceramic materials.     

Molar heat capacities of La2Mo2O9 and La1.9Sr0.1MO209-δ

The molar heat capacities of La2Mo209 and La1.9Sr0.1MO209-δ were obtained using the differential scanning calorimetry （DSC） technique in a temperature range from 298 to 1473 K. The DSC curve of La2Mo209 showed an endothermal peak around 834 K corresponding to a first-order monoclinic-cubic phase transition, and the enthalpy change accompanying this phase transition is 5.99 kJ/mol. No evident endothermal peak existed in the DSC curve of La1.9Sr0.1MO209-δ, but a broad thermal anomaly existed in its heat capacity curve at around 832 K. In addition, the heat capacity values of La2Mo209 and La1.9Sr0.1MO209-δ began to decrease at 1196 and 1330 K, respectively. The non-transitional heat capacity values of La2Mo209 and La1.9Sr0.1MO209-δ were formulated using multiple regression analysis in two temperature ranges.     

纳米Al2O3改性环氧胶黏剂和钢铁附着机理的研究

通过拉拔法测定纳米Al₂O₃改性环氧胶黏剂和钢铁之间的附着强度,并结合环氧胶的表面能参数测定以及X射线光电子能谱(XPS)分析,对纳米Al₂O₃提高环氧胶和钢铁附着力的机理进行研究.表面能测定结果表明,添加纳米Al₂O₃使环氧胶的极性增加;XPS能谱分析结果表明,当纳米Al₂O₃质量分数达到2%时,环氧胶中形成新的羧基极性基团;进一步研究发现,当纳米Al₂O₃质量分数为1%时未形成新的羧基基团,当纳米Al₂O₃质量分数为8%时单位接触面积上新的羧基基团的数目较2%时少,这与附着强度的变化规律是一致的.因此,纳米Al₂O₃改性的环氧胶黏剂与钢铁的附着强度的增强是由于Al₂O₃与环氧胶的相互作用形成了新的羧基极性基团．     

Properties of plasma sprayed NiCrAlY+(ZrO2+Y2O3) coating on refractory steel surface

NiCrAlY+(ZrO₂+Y₂O₃) thermal barrier coating was prepared on the surface of refractory steel 1Cr18Ni9Ti with plasma spraying technique. The phases and microstructure of the thermal barrier coating were determined by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results show that the bonding between thermal barrier coating and substrate is sound. The surface hardness of 1Cr18Ni9Ti reaches up to 1 000 HV, but that of substrate is only 300 HV. The patterns sprayed with CoNiCrAlY+(ZrO₂+Y₂O₃) ceramic coating have a good heat insulation effect at 800 °C for heat insulation temperature difference reaches 54 °C, which increases the operating temperature and service life of refractory steel. Foundation item: Project (5040202140) supported by Scientific Research Common Program of Beijing Municipal Commission of Education     

采用微生物覆铜板浸出液中铁离子制备 Fe2O3/石墨烯纳米复合材料的研究

针对微生物法覆铜板浸出液中的金属铁离子进行资源化处理,提高覆铜板浸出液的附加值。以水热法处理得到的铁离子溶液为原料,制备八面体和球形的Fe_2O_3/石墨烯复合材料,并将其作为锂离子电池负极材料,组装成扣式电池。结果显示:八面体形貌的Fe_2O_3/石墨烯复合材料的比容量高于球形的,其在100 mA/g电流下循环,首次放电和充电比容量分别高达1 343和970 mAh/g,在47次循环后,其放电及充电比容量分别为769和740 mAh/g。     

TiO2/ML-Ti3C2复合纳米材料的制备及其光催化性能

通过水热技术在二维(2D)多层材料Ti_3C_2 (multi-layer Ti_3C_2, ML-Ti_3C_2)的表面及层间原位晶化和生长锐钛矿相TiO_2纳米球,制备出TiO_2/ML-Ti_3C_2复合纳米材料。采用XRD、SEM、氮吸附等表征技术对TiO_2/ML-Ti_3C_2纳米复合材料进行分析表征,并以亚甲基蓝(MB)为模拟污染物,对纯TiO_2和TiO_2/ML-Ti_3C_2复合纳米材料的光催化性能进行了评价。实验结果表明,两种材料的耦合抑制了Ti O_2中光生电子-空穴对的湮灭,延长了复合光催化剂中载流子寿命,拓宽了复合材料的光谱响应范围。在紫外光照射下,以TiO_2/ML-Ti_3C_2复合纳米材料为光催化剂,200 mg/L的MB溶液在20 min内几乎完全脱色,降解率为98.98%。TiO_2/ML-Ti_3C_2纳米复合材料的光催化性能优于纯TiO_2和Ti_3C_2, Ti_3C_2优异的电子传输能力和超强的吸附性能优化了TiO_2的光催化性能。本研究为使用光催化技术处理废水提供了一种新的思路,具有一定的实际应用前景。     

Solvothermal preparation and characteristics of Sn-doped In2O3

Sn-doped In2O3 （ITO） nanopowders were prepared in ethanol solvent by solvothermal process. The effects of the solvothermal temperature, coprecipitation pH value and SnO2 content on the products phase and microwave absorption were investigated by X-ray diffractometry and microwave reflectance. ITO nanopowders with cubic structure can be respectively prepared at 250 and 270 ℃ for 6 h. The prepared product is InOOH or the mixture of InOOH and In3Sn4O12 when the solvothermal temperature is below 250℃. With rising solvothermal temperature and prolonging time, the absorption of the ITO powders gradually decreases. The products are ITO nanopowders by coprecipitating at pH=9 or 11, but ITO powders with Sn3O4 at pH=6. The absorption of powders prepared at pH=6 is better than that at any other pH value. The products are all ITO nanopowders and crystal size reduces with increasing SnO2 content. The microwave absorption of ITO nanopowders with SnO2 content of 8% （mass fraction） is the best among samples with different SnO2 contents.