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。     

化学链燃烧中Co掺杂改性Fe_2O_3(104)载氧体反应特性

基于密度泛函理论建立金属Co掺杂的铁基载氧体的微观模型,探究掺杂Co后模型表面的电子结构及反应特性的变化。首先,采用Material Studio软件中CASTEP模块构建并优化Fe_2O_3(104)的平板模型;其次,以Co原子分别替换模型表面不同配位数的Fe原子(Fe5f,Fe6f和Fe7f),构建Co在表面不同Fe原子位的掺杂模型(Co–Fe_2O_3(104));最后,计算纯净模型和掺杂模型的表面能、掺杂结合能、态密度以及掺杂位点原子的键长、键角和原子间距离等参数,考察CO在Fe_2O_3(104)和Co掺杂的Fe_2O_3(104)表面的等温吸附特性,并以CO分子为探针测试Co掺杂模型和纯净模型表面的氧化反应特性,获取反应路径、过渡态和反应活化能等信息。几何优化结果得到Co掺杂模型的稳定性顺序是:Co5f–Fe_2O_3(104) Co6f–Fe_2O_3(104) Co7f–Fe_2O_3(104),对应的结合能分别为–0.399 eV、–0.215 eV和0.487 eV,Co在Fe5f和Fe6f位的掺杂是放热过程,并且在Fe5f原子位的掺杂时放热较多,而在Fe7f原子的掺杂属于是吸热反应;Co掺杂改变了掺杂位点相邻O原子的平均键长LO-M(M代表Fe或Co),其中Co替换Fe7f后相邻O原子的LO-M增加了0.004 4 nm;掺杂Co后模型的总态密度(DOS)均向费米能级(0 eV)方向移动,在–8 eV～0 eV能量范围内离域性增强,而且Co5f–Fe_2O_3(104)模型体系靠近费米能级左边的填充态能量高于其他模型。等温吸附表明Co掺杂可以提高CO在模型表面的吸附量,并且存在吸附两种方式:–2.0 eV附近的峰为CO模型表面碱性位点的吸附峰,–0.75 eV附近的峰为CO在非碱性位点的吸附峰。CO在Co5f–Fe_2O_3(104)表面的吸附能(–0.851 eV)最大,而在Co7f–Fe_2O_3(104)表面的吸附需要外加能量(0.386 eV),CO在Co6f和Co7f掺杂位吸附的键长(LCO)比纯净模型表面的分别增加了0.000 4 nm和0.001 1 nm,表明Co掺杂表面对CO分子的活化作用较大;过渡态分析表明CO在Co掺杂表面氧化生成CO2的反应活化能均明显下降,其中CO在Co5f–Fe_2O_3(104)表面生成CO2的活化能最低,比在Fe_2O_3(104)表面的减少了0.518 eV,且相应的反应能增加了0.445 eV。研究表明,Co与Fe在其氧化物中成键结构不同,导致掺杂后模型表面的悬键增多,表面能增大,态密度向费米能级方向移动,提高了Fe_2O_3(104)表面活性,并且Co在低配位数Fe原子位的掺杂更有利于降低氧化CO的反应活化能。因此,通过掺杂金属Co提高铁基载氧体反应活性是可行的,其改性效果与掺杂活性成分的特性和掺杂方式有密切的关系。     

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.     

酞菁铜对纳米α-Fe2O3光催化剂的表面改性

为推动纳米氧化铁基光催化材料在水体环境修复领域中的应用,针对氧化铁半导体导带底能级位置较正而导致的光生电子热力学还原能力不足及其表面催化活化O₂位点少的科学问题,在控制合成小尺寸纳米氧化铁的基础上,通过复合改性实现对其光生电子的有效调控是关键. 首先利用尿素调制的相分离水解-溶剂热法制备了小尺寸纯相α-Fe₂O₃.在此基础上, 通过简单的湿化学法实现了CuPc对α-Fe₂O₃纳米粒子的表面改性. 结果表明:所获得的最佳样品（CuPc和α-Fe₂O₃的质量比为1%）的光催化降解2,4-二氯苯酚（2,4-DCP）的活性达到了纯α-Fe₂O₃的2.5倍;利用紫外-可见漫反射光谱(DRS)、傅里叶红外光谱(FT-IR)、激光拉曼光谱(Raman)等手段对其进行了结构表征,揭示了CuPc与α-Fe₂O₃之间通过氢键作用实现有效连接;基于羟基自由基荧光测试及电化学分析表明光催化活性提高的主要原因有:CuPc的引入有效改善了其光生电荷分离效率,并且进一步促进了O₂的活化;CuPc对长波可见光的特征吸收进一步改善了其可见光利用范围.该策略也适用于其他过渡金属酞菁对α-Fe₂O₃的修饰,并且均改善了α-Fe₂O₃的光催化性能.     

Fe2O3对污泥与底泥制备轻质陶粒性能的影响

为研究在以污水污泥和河道底泥为主要原料制取轻质陶粒过程中,Fe₂O₃质量分数对陶粒性能的影响,对陶粒的物理性能、表面形态、抗压强度和晶体构成进行研究,结果表明,Fe₂O₃质量分数在3.5％～7％时,可取得松散容重和表观密度较高、吸水率比较小、抗压强度较高的陶粒．扫描电子显微镜(SEM)分析表明,随着Fe₂O₃质量分数的增加,陶粒表面玻璃化效果明显．在Fe₂O₃质量分数为5％时,可得到致密性较好、表面微孔分布均匀的陶粒．Fe₂O₃质量分数在3.5％～7％时,陶粒的抗压性能良好(14 MPa以上)．X射线衍射分析(XRD)表明,陶粒中主要晶体为石英、钠钙长石、蓝晶石和赤铁矿,内部以稳定的硅酸盐晶体为主．随着Fe₂O₃质量分数的增加,更多的Fe₂O₃可以在高温条件下转换为晶体结构的赤铁矿．在利用污水污泥与河道底泥制取轻质陶粒的过程中,控制Fe₂O₃质量分数在3.5％～7％较合适．     

负载型γ-Al2O3三维粒子电极的制备及其对氯霉素的降解

以γ-Al₂O₃为载体,将Ti和Sn两种元素进行负载制备负载型γ-Al₂O₃粒子电极,采用X射线衍射（XRD）、扫描电镜（SEM）、X射线荧光光谱（XRF）、红外光谱（IR）对γ-Al₂O₃和负载型γ-Al₂O₃粒子电极进行表征。研究了电解时间对三维粒子电极法电催化氧化氯霉素的影响。采用初始浓度100 mg/L的CAP模拟废水,持续电解3 h后,制备的粒子电极通过三维电解对CAP去除率为72.8%,对TOC去除率低于3.7%,说明负载型γ-Al₂O₃粒子电极对氯霉素矿化作用较小。三维粒子电极对氯霉素的降解过程近似符合一级动力学方程,CAP初始浓度对去除率影响较小。粒子电极电催化氧化CAP的关键因素之一为·OH,外加叔丁醇对·OH进行清洗,相同条件下,氯霉素去除率降低至30%左右,表明氯霉素的降解是由阳极氧化和·OH间接氧化两种途径协同作用的。     

含钪赤泥氯化钠离析焙烧-弱磁选-盐酸浸出分离铁、钪试验研究

针对云南含钪赤泥原矿含TFe 25.68%、Sc₂O₃ 70.66 g/t,钪主要以类质同象形式分散于金红石、辉石、长石、白云母、方解石等矿物中,铁、钪分离困难,提出了氯化钠离析焙烧-弱磁选-盐酸浸出的选冶联合工艺处理该含钪赤泥,使铁从赤铁矿转为以金属铁、磁铁矿为主的新物相,破坏载钪矿物的晶体结构,为铁、钪分离创造有利条件。试验结果表明：在离析焙烧温度950 ℃、离析焙烧时间60 min、氯化钠用量10%、焦炭用量15%、焦炭粒度-0.5～0.25 mm、弱磁选磁场强度H=0.12 T、弱磁选磨矿细度为<0.045 mm占95%、盐酸用量30%、浸出温度55 ℃、浸出时间120 min、浸出液固比 R =2∶3的综合工艺条件下,获得了铁品位为73.99%,含钪5.22 g/t,铁回收率为88.99%的铁精矿;钪浸出率为96.78%,浸出渣中的钪含量为6.37 g/t,铁、钪分离效果显著。MLA、SEM、EPMA分析结果显示：含钪赤泥经过氯化钠离析焙烧后,铁从赤铁矿（Fe₂O₃）转变为以金属铁（Fe）、磁铁矿（Fe₃O₄）为主的新铁物相及少量的氧化亚铁（FeO）、硅酸铁（Fe₂SiO₄）;浸出渣主要成分为SiO₂、CaO、Al₂O₃,与浸出前相比较,CaO、Al₂O₃降低比较明显,浸出渣中没有明显的Sc谱线峰值,这表明弱磁选尾矿经盐酸浸出后,钪绝大部分被溶解掉进入浸出液中,且钪的溶解较为彻底,也进一步验证了含钪赤泥采用氯化钠离析焙烧-弱磁选-盐酸浸出分离铁、钪比较合理,且铁、钪分离效果显著。     

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．     

块体SmCo7/Nd2Fe14B异质纳米复合永磁体的微结构和磁性能

采用高压热压缩变形技术对高能球磨的SmCo基非晶-纳米晶粉体与商用的Nd-Fe-B纳米晶粉体的混合物冷压块进行变形处理,成功制备出块体各向异性SmCo₇/Nd₂Fe₁₄B异质纳米复合永磁体。通过X射线衍射仪（XRD）、透射电子显微镜（TEM）以及振动样品磁强计（VSM）对块体SmCo₇/Nd₂Fe₁₄B异质纳米复合永磁体的微结构和磁性能进行分析研究得出：所制备磁体的微结构由SmCo₇/Nd₂Fe₁₄B纳米晶区域组成,且SmCo₇/Nd₂Fe₁₄B纳米晶具有沿其（00l）方向（平行于压力方向）的择优取向;磁体具有明显的磁各向异性,室温下沿压力方向具有16 MGOe的最大磁能积;磁体具有较好的温度稳定性,其矫顽力温度系数β_{（RT-250℃）}=-0.26%℃^-1。研究结果表明,所制备磁体具有较高的潜力,可应用于国防军工、轨道交通等科技领域。     

SO2浸出软锰矿体系连二硫酸锰的生成机制

副产物连二硫酸锰(MnS₂O₆)生成是限制废气二氧化硫还原浸出软锰矿副产硫酸锰工艺工业化应用的技术瓶颈和关键科学问题。迄今,MnS₂O₆的生成机制尚未明确,难以为探究其工艺控制措施提供有效理论依据。基于此,本文研究了SO₂浸出软锰矿体系MnS₂O₆的生成机制,阐明了MnS₂O₆生成速率控制步骤和动力学过程。首先基于反应体系理论分析,提出基于表面吸附和电化学模型的自由基生成机制可用于解释MnS₂O₆的生成机制,其生成速率微观上取决于自由基HSO₃形成速率,宏观上主要取决于体系H^₊和HSO- 3浓度,两者的反应级数均为1,推导的理论生成速率方程为 。随后通过动力学实验考察了体系SO₂浓度、pH和温度对MnS₂O₆生成的影响,研究结果表明,MnS₂O₆生成速率随体系酸度和温度的升高呈现先快速减小后趋势趋缓,随体系SO₂浓度的升高而升高,H^₊和SO₂浓度对MnS₂O₆生成速率的反应级数分别为-0.057和0.9954,反应的活化能为6894.05 J/mol。最后基于液相SO₂解离平衡关系,推导得到H^₊浓度和HSO- 3浓度对MnS₂O₆生成速率的反应级数分别为0.943和0.996,与理论速率方程的级数非常接近。研究结果验证了对MnS₂O₆生成机制的解释和动力学推导过程, 可为该工艺工业化应用时MnS₂O₆生成特性及抑制方法研究提供理论依据和有效途径。     

Ba3La2Ti2Ta2O15: A new microwave dielectric of A5B4O15-type cation-deficient perovskites

The synthesis, structure and properties of a new A5B4O15-type cation-deficient perovskite Ba3La2Ti2Ta2O15 were discribed. The compound was prepared by the conventional solid-state reaction route. The phase and structure of the ceramics were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）. The results reveal that the compound is successfully synthesized. The compound crystallizes in the trigonal system with unit cell parameter a=5.6730（2） A, c=11.6511（2） A, V=324.93（1） A^3 and Z=1. The microwave dielectric properties of the ceramic are studied using a network analyzer, and it shows a high dielectric constant of 45.1, a high quality factors with Q×fof21 029 GHz, and a positive τf of 5.3 ppm℃^-1.     

Electrical conductivity of （Na3AlF6-40%K3AlF6）-AlF3-Al2O3 melts

The effects of contents of AlF3 and Al2O3, and temperature on electrical conductivity of （Na3AlF6-40%K3AlF6）- AlF3-Al2O3 were studied by continuously varying cell censtant （CVCC） technique. The results show that the conductivities of melts increase with the increase of temperature, but by different extents. Every increasing 10 ℃ results in an increase of 1.85 × 10^-2, 1.86× 10^-2, 1.89 × 10^-2 and 2.20 × 10^-2 S/cm in conductivity for the （Na3AlF6-40%K3AlF6）-AlF3 melts containing 0%, 20%, 24%, and 30% AlF3, respectively. An increase of every 10 ℃ in temperature results an increase about 1.89× 10^-2, 1.94 × 10^-2, 1.95 × 10^-2, 1.99× 10^-2 and 2.10× 10^-2 S/cm for （Na3AlF6-40%K3AlF6）-AlF3-Al2O3 melts containing 0%, 1%, 2%, 3% and 4% Al2O3, respectively. The activation energy of conductance was calculated based on Arrhenius equation. Every increasing 1% of AlF3 results in a decrease of 0.019 and 0.020 S/cm in conductivity for （Na3AlF6-40%K3AlF6）-AlF3 melts at 900 and 1 000 ℃, respectively. Every increase of 1% Al2O3 results in a decrease of 0.07 S/cm in conductivity for （Na3AlF6-40%K3AlF6）-AlF3-Al2O3 melts. The activation energy of conductance increases with the increase in content of AlF3 and Al2O3.     

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     

Ca0.9Ce0.1Ti0.8Al0.2SiO5在水热作用下的化学稳定性

通过固相法合成掺铈榍石固溶体(Ca0.9 Ce0.1Ti0.8Al0.2SiO5),采用PCT粉末浸泡试验法,借助X射线衍射(XRD)、扫描电镜(SEM)、电感耦合等离子体发射光谱(ICP-OES)等分析测试手段,研究掺铈榍石固溶体在热液作用下的稳定性.实验结果表明,掺铈榍石固化体在不同条件下(温度150～ 200℃,0.476～1.554 MPa,pH值5～9),都具有良好的稳定性.随着浸泡时间的增加,各元素的归一化浸出率逐渐降低并保持在较低水平.     

Preparation and electrical-magnetic properties of Co0.6Cu0.16Ni0.24Fe2O4/MWCNTs composites

Co0.6Cu0.16Ni0.24Fe2O4/multi-walled carbon nanotube nanocomposites (CCNF/MWCNTs) were synthesized by solution filling method.The phase structure,thermal stability,morphology and electrical-magnetic properties of the samples were characterized by means of modern testing technology.The effect of iron concentration,filling time,sintering temperature on their electrical and magnetic performance was discussed.The results indicated that conductivity was related to the content of MWCNTs,while the magnetism correlated with the volume fraction of the filled CCNF in the composites.When the optimal condition satisfied the filling time of 18 h,ferric concentration of 0.25 mol L-1 and sintering temperature of 350°C,the prepared composite had the best magnetic loss performance,and its minimum reflection loss reached-22.47 dB on 9.76 GHz,the available bandwidth was beyond 2.0 GHz.Hence,the obtained composite can be used as advancing absorption and shielding material due to its favorable microwave absorbing property.     

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.     

Electrolysis expansion performance of semigraphitic cathode in [K3AlF6/Na3AlF6]-AlF3-Al2O3 bath system

The electrolysis expansion of semigraphitic cathode in [K₃AlF₆/Na₃AlF₆]-AlF₃-Al₂O₃ bath system was tested by self-made modified Rapoport apparatus. A mathematical model was introduced to discuss the effects of α _CR (cryolite ratio) and β _KR (elpasolite content divided by the total amount of elpasolite and sodium cryolite) on performance of cathode electrolysis expansion. The results show that K and Na (potassium and sodium) penetrate into the cathode together and have an obvious influence on the performance of cathode electrolysis expansion. The electrolysis expansion and K/Na penetration rate increase with the increase of α _CR. When α _CR=1.9 and β _KR=0.5, the electrolysis expansion is the highest, which is 3.95%; and when α _CR=1.4 and β _KR=0.1, the electrolysis expansion is the lowest, which is 1.28%. But the effect of β _KR is correlative with α _CR. When α _CR=1.6 and 1.9, with the increase of β _KR, the electrolysis expansion and K/Na penetration rate increase. However, when α _CR=1.4, the electrolysis expansion and K/Na penetration rate firstly increase and then decrease with the increase of β _KR. Foundation item: Project (2005CB623703) supported by the Major State Basic Research and Development Program of China; Project (2008AA030502) supported by the National High-Tech Research and Development Program of China     

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)     

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.     

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.