Ce1-xGdxO2-x/2的溶胶-凝胶法合成及其性质

利用溶胶-凝胶法合成了Ce₁-xGdxO_2-x/2(x=0.1～0.6)系列固体电解质,系统地研究了其结构、热膨胀系数和导电性.XRD结果表明,160℃即完全形成立方萤石结构.由于溶胶-凝胶法合成的物质粒度均匀,颗粒小,故在较低温度(1300℃)时即可形成高致密样品,此温度明显低于传统的高温固相法烧结温度(1600～1650℃).高温X射线衍射测得Ce_0.8Gd_0.2O_1.9的热膨胀系数为8.125×10^-6K₁.阻抗谱表明,溶胶-凝胶法合成可减少或消除固体电解质的晶界电阻,600℃时Ce_0.8Gd_0.2O_1.9的电导率为5.26×10^-3S/cm,活化能E_a=0.82eV.     

锂磷氧氮(LiPON)薄膜电解质和全固态薄膜锂电池研究

采用电子束热蒸发Li₃PO₄与氮等离子体辅助相结合的方法制备了含氮磷酸锂(LiPON)电解质薄膜,已测得该非晶态电解质薄膜在温度为300K时的离子导电率为6.0×10^-7 S/cm,电子电导率低于10^-10 S/cm,电化学稳定窗口为5.0V.以脉冲激光沉积法(PLD)制备的非晶态Ag_0.5V₂O₅薄膜为阴极,真空热蒸发法制备的金属锂为阳极,LiPON薄膜为电解质,成功地制备了一个新的Li/LiPON/Ag_0.5V₂O₅全固态薄膜锂电池.该电池以14μA/cm²电流充/放电时,首次放电容量达到62 μAh·cm^-2·μm^-1,10次循环后容量衰减缓慢,衰减率约为0.2%,循环寿命达到550次以上.     

La掺杂钛酸钙光催化剂在可见光下分解水制氢的影响因素

以柠檬酸为络合剂, 采用溶胶-凝胶法制备了钙钛矿型光催化剂Ca_0.99La_0.01TiO₃, 利用X射线衍射仪(XRD)、 扫描电子显微镜(SEM)、 紫外-可见漫反射光谱仪(UV-Vis DRS)等对光催化剂材料进行了表征, 并考察了N掺杂对光催化剂催化效果的影响, 探究了可见光条件下, Ca_0.99La_0.01TiO_3-xN_x在不同Pt负载量及不同种类牺牲剂中光催化分解水的产氢量, 并进行相关荧光猝灭分析. 结果表明, 在可见光条件下, Pt负载量为1%且掺杂N的钙钛矿光催化剂在Na₂SO₃/Na₂S作为牺牲剂时, 光催化分解水的产氢量最高.     

LiNi0.3Co0.7O2的结构及其锂电池行为的研究

利用XRD、XPS、CV等方法研究了LiNi_0.3Co_0.7O₂的结构及其锂电池行为。结果表明:LiNi_0.3Co_0.7O₂具有六方晶系空间群结构,其晶胞参数a=0.2826nm,c=1.4130nm;其表面存在Li₂O;Li⁺在其中的化学扩散系数为1～7×10^-8cm²·s^-1;其锂电池在4.30～3.00V间放电容量可达120～140mA·h·g^-1,放电机理为Li⁺在其中进行两步嵌入反应。     

以脲和硫氰酸盐为主体的高分子固体电解质的研究

在熔盐体系相图指导下研制出以脲和硫氰酸铵(钾)为主体的高分子固体电解质(PSE),其室温电导率分别为1.20×10^-2和2.65×10^-3S/cm.考察了影响该PSE电导率的因素,讨论了PSE的导电机理.结果表明,所研制的PSE为无定形固熔体,主要通过硫氰酸盐的电离导电,电导率-温度关系服从VTF方程.     

石榴石Li7La3Zr2O12固态电解质电导率优化策略研究进展

近几年,应用碳材料负极和有机电解液的液态锂离子电池(LIBs)的弊端日益凸显,电解液泄漏和过热燃烧等安全事故频发。另外,传统的LIBs也无法满足当今社会对高能量密度电池的需求。由于上述LIBs存在的诸多缺点,市场急需开发兼顾高能量密度与高安全性能的新型电池,现已发现可通过引入固态电解质的途径来实现。固态锂电池(SSLBs)相较于传统的LIBs,具有较高的能量密度、较宽的工作温度范围和更高的安全性。其中,固态电解质作为固态电池的重要元件之一,对电池性能的影响至关重要。石榴石Li₇La₃Zr₂O₁₂凭借其高锂离子电导率(1×10^-4～1×10^-3 S/cm)、宽电化学窗口(9 V)以及对锂负极的高稳定性等优点,在众多固态电解质中脱颖而出。本综述就提高石榴石基电解质锂离子电导率的研究予以总结：首先,介绍了Li₇La₃Zr₂O₁₂晶体结构并分析了结构与电导率之间的关系;然后,综...     

芳香查尔酮衍生物的合成、理论计算及三阶非线性光学性质

合成了2种新的具有潜在应用价值的非线性光学(NLO)有机材料芳香查尔酮衍生物1-(呋喃-2-基)-3-(4-甲氧基苯基)丙烯酮(1)和1-(噻吩-2-基)-3-(4-甲氧基苯基)丙烯酮(2),并对其进行了NMR、IR和HR-MS结构表征。 采用4f相位相干成像技术测定了化合物1和2的三阶NLO性质并确定了相关参数:脉冲宽度4 nm,激光波长440 nm,化合物1:非线性吸收系数β=5.5×10^-10 m/W,非线性折射系数n₂=-2.1×10^-17 m²/W,三阶非线性极化率χ⁽³⁾=1.58×10^-11 esu;化合物2:β=-2.4×10^-10 m/W,n₂=0.3×10^-17 m²/W,χ⁽³⁾=0.50×10^-11 esu;并测定了紫外光谱和DSC曲线。 采用密度泛函方法计算了化合物1和2的轨道能量和极化率,结果表明电子转移能在分子内部进行,说明比较易于极化,展示了良好的非线性光学性质。     

Integrated interface between composite electrolyte and cathode with low resistance enables ultra-long cycle-lifetime in solid-state lithium-metal batteries

We report a three-dimensional(3D)nanofiber-reinforced solid composite electrolyte with a 3D Li⁺-conducting ceramic network of Li_6.25Ga_0.25La₃Zr₂O₁₂(LLZO)nanofibers.Benefiting from the 3D structure,the composite shows a high ionic conductivity of 3.2×10^-4S cm^-1and Li-ion transference number of 0.32 at room temperature.The interfacial resistance between the composite solid electrolyte and cathode is mitigated by creating an integrated interfacial structure,in which the polyethylene oxide(PEO)-lithiumbis(trifluoromethylsulphonyl)imide(LiTFSI)binder and ionic liquids(ILs)form a viscoelastic interface.Therefore,intimate contact,low interfacial impedance,and fast ion-transport between the cathode and the solid electrolyte are simultaneously achieved.Solid-state lithium metal batteries with the Li Fe PO₄ cathode deliver a superior capacity(158.0 m A h g^-1)and significant capacity retention(90.4%retention after 800 cycles)at 60℃.Moreover,the smooth and uniform Li surface after long-term cycling confirms the successful suppression of the dendrite formation.The integrated interfacial structure provides a solution to the interfacial problem and improves the cycling performance in solid-state Li-metal batteries.     

新型室温熔盐二(三氟甲基磺酸酰)亚胺锂-乙酰胺/乙烯脲体系的研究

制备了二(三氟甲基磺酸酰)亚胺锂[LiN(SO₂CF₃)₂,LiTFSI]与乙酰胺和乙烯脲形成的新型室温熔盐,分析了其热学和电化学性能.LiTFSI-乙酰胺体系的热学稳定性好,低共熔温度为-62.18℃.电化学测试表明,LiTFSI-乙酰胺体系的电导率较高,n(LiTFSI):n(Acetamide)=1:6.5样品的室温电导率为1.08×10^-3S/cm,60℃时电导率为5.35×10^-3S/cm;摩尔比为1:4.0样品的电化学稳定电位窗为3V左右.     

LiCoO2 sintering aid towards cathode-interface-enhanced garnet electrolytes

Garnet-type Li₇La₃Zr₂O₁₂(LLZO) has high ionic conductivity and good compatibility with lithium metal.High-temperature processing has been proven an effective method to decrease the interface resistance of cathodeILLZO.However,its application is still hindered by the interlayer co-diffusion with the cathode and high sintering temperature(>1200℃).In this work,a new garnet-type composite solid-state electrolyte(SSE) Li_6.54La_2.96Ba...     

Synthesis of Monoclinic Li_(0.33)MnO_2 and Its Electrochemical Properties in Different Potential Windows

Li0.33MnO2 cathode material was synthesized by solid state reaction. The material showed a small coherent domain size about 10 nm determined by X-ray diffraction and transmission electron microscopy. The electrochemical properties of the material were studied in different potential windows of 3.5―2.0 V and 4.3―2.0 V. An irreversible transformation to spinel phase was observed in the initial several cycles, which was more prominent on cycling at 4.3―2.0 V. Electrochemical impedance spectroscopy showed that the Li+ diffusion coefficient of the material was about 2×10–9 cm2/s. Li0.33MnO2 showed a reversible discharge capacity of 140 and 200 mA·h/g in the potential windows of 3.5―2.0 V and 4.3―2.0 V, respectively. But the capacity retention at 4.3―2.0 V was poor due to the thicker spinel layer formed on the material surface.     

Studies on a New System of Lithium Fast Ion Conductors Based on Kaolinite and LiZr_2(PO_4)_3

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Effect of promoter Ce on silver-molybdenum-phosphate catalysts for selective oxidation of propane to acrolein

A series of Me_nAg_0.3Mo_0.5P_0.3O_y (Me=Cu, Zn, Mn, W, Ce, Pr, Nd) and Ag_0.3Mo_0.5P_0.3O_x catalysts were prepared. The addition of Ce to Ag_0.3Mo_0.5P_0.3O_x catalysts improved the catalytic performance in selective oxidation of propane to acrolein, and Ce_0.1Ag_0.3Mo_0.5P_0.3O_x catalysts showed the highest acrolein selectivity (28.7%) and yield (4.4%). The physicochemical properties of Ag_0.3Mo_0.5P_0.3O_x and Ce_nAg_0.3Mo_0.5P_0.3O_x (n=0.1–0.5) catalysts have been comparatively characterized by BET, XRD, H₂-TPR, XPS, EPR and C₃H₈(C₃H₆)-TPD. Significant differences in physicochemical properties between Ag_0.3Mo_0.5P_0.3O_x and Ce doped Ag_0.3Mo_0.5P_0.3O_x catalysts have been observed, which is due to the formation of the redox cycle (Ce³⁺+Mo⁶⁺Ce⁴⁺+Mo⁵⁺) in the Ce_nAg_0.3Mo_0.5P_0.3O_y catalyst. Such effect modified the reducibility, the concentration of Mo⁵⁺, the activation of propane and the transformation of possible intermediate propene to acroelin, which in return greatly influenced the catalytic performance of Ce doped Ag_0.3Mo_0.5P_0.3O_x catalysts in selective oxidation of propane to acroelin. The proper addition of Ce to Ag_0.3Mo_0.5P_0.3O_x catalyst improved the acrolein selectivity and yield.     

Na掺杂Li2-xNaxMnSiO4/C正极材料的微波辅助合成与电化学性能

采用溶胶-凝胶法并辅以微波热处理合成了Na掺杂改性的Li_2-xNa_xMnSiO₄/C(x=0, 0.05, 0.09, 0.13)复合正极材料. 利用X射线衍射(XRD)、 扫描电子显微镜(SEM)、 恒电流充放电测试、 循环伏安(CV)和交流阻抗(EIS)测试等对材料进行了表征. 结果表明, 经微波辐射后得到的电极材料具有Pmn2₁型空间结构, 其碳层分布均匀, 粒径细小均匀, 约为15~30 nm. 在微波辅助原位碳包覆和Na掺杂共同作用下, 复合材料的电荷转移电阻明显降低, Li⁺扩散速率增大, 展现出优良的电化学性能. 在0.1C倍率下Li_1.91Na_0.09MnSiO₄/C样品首次放电比容量为211 mA∙h/g, 50次循环后仍保持80 mA∙h/g的可逆容量; 0.5C和2.0C倍率下的放电比容量分别为106和53 mA∙h/g, 大电流下的可逆容量明显提高.     

多环芳烃芴、苊的无保护流体室温磷光性质研究

我们[1,2 ]曾报道丹磺酰氯及其衍生物在无保护性介质亦无有机溶剂存在的水溶液中能诱导出强而稳定的室温磷光 (ＲＴＰ) ,并命名为ＮＰ ＲＴＰ[37].此后 ,Ｃａｒｒｅｔｅｒｏ等[810 ]亦发现了萘唑啉、萘氧乙酸和苊溶液在无任何有序介质时的ＲＴＰ发射现象 .在已有的研究中至少有两个问题需进一步探索 :其一 ,除苊外 ,已实现ＮＰ ＲＴＰ发射的化合物都仅具双环结构 ,即萘系化合物 ,对于多环化合物是否有类似的发射特性和随环的增多是否会出现新的特性 ;其二 ,对于无水溶性取代基的多环芳烃 ,因其在水中的溶解度很小 ,所引入的有机溶剂的种类和…     

Zn-Al-[V_(10)O_(28)]~(6-)双层氢氧化物掺杂对LY12铝合金表面溶胶-凝胶涂层性能的影响

采用共沉淀法制备Zn-Al-[V10O28]6-双层氢氧化物(以下简称LDH-V),研究不同添加浓度(0.0、0.25×10-3、0.75×10-3、1.5×10-3、3.0×10-3mol·L-1)的LDH-V对LY12铝合金溶胶-凝胶涂层形貌、耐蚀性的影响.采用扫描电子显微镜(SEM)和傅里叶变换红外(FTIR)光谱研究LDH-V对涂层形貌和结构的影响.运用中性盐雾实验对涂层进行耐蚀性评估.利用电化学方法对涂层在0.05 mol·L-1的NaCl溶液中的腐蚀行为进行研究.探讨加入LDH-V后溶胶-凝胶涂层的耐蚀机理.结果表明,一定量LDH-V的加入不仅可以提高溶胶-凝胶涂层的耐蚀性能,还可对涂层被破坏区域进行自修复,起到延缓铝合金基体腐蚀的作用.然而,当LDH-V的添加溶度超过一定值时,会破坏涂层的完整性并降低涂层的腐蚀防护性能.实验结果表明LDH-V最佳的添加浓度为1.5×10-3mol·L-1.     

Mechanism of Lithium and Cobalt Recovery from Spent Lithium-ion Batteries by Sulfation Roasting Process

Different from the traditional pyrometallurgical recovery process of Li and Co from spent lithium-ion batteries, a new recovery method for Li and Co was established by converting LiCoO₂ into water-soluble metal sulfates by roasting a mixture of LiCoO₂ and NaHSO₄·H₂O. The evolution law of the mixture with increased roasting temperature was investigated by thermogravimetry-differential scanning calorimetry(TG-DSC), in situ X-ray diffraction(XRD), XRD, and X-ray photoelectron spectroscopy(XPS). The results show that the phase transition of LiCoO₂ mixed with NaHSO₄·H₂O with increased temperature proceeded as follows:LiCoO₂, NaHSO₄·H₂O→LiCoO₂, NaHSO₄→Li_1-xCoO₂, LiNaSO₄, Na₂S₂O₇, Na₂SO₄→Li_1-xCoO₂, Co₃O₄, LiNaSO₄, Na₂SO₄→Co₃O₄, LiNaSO₄. The reaction mechanism of this roasting process may be as follows:LiCoO₂+NaHSO₄·H₂O→1/2Li₂SO₄+ 1/2Na₂SO₄+1/3Co₃O₄+1/12O₂+3/2H₂O, Li₂SO₄+Na₂SO₄=2LiNaSO₄.     

锂钠复合超价氧化物的电子结构和稳定性

采用6-31G^*基组,用B3LYP密度泛函方法,对OLi_nNa₂(n=1-4)及OLi₂Na系列分子的所有可能结构进行了几何优化和频率计算,得到各分子的几种能量极小点.除OLi₄Na₂采取D_2d对称性外,该系列其它4种分子都采取C_2v对称作为它们的能量最低点.OLi_nNa₂(n=2,3,4)分子解离出一个Li原子的离解能分别为212.25432,68.49208和245.55896kJ/mol,表明此类分子在热力学上是相当稳定的.