The structural and dielectric properties of Ba0.92Sr0.08Ti0.95Sn0.0503 （BSTS） ＋x（molar ratio, %） Y^3＋ceramics are investigated. Combining the lattice parameters and the distortion of crystal lattice, an alternat...The structural and dielectric properties of Ba0.92Sr0.08Ti0.95Sn0.0503 （BSTS） ＋x（molar ratio, %） Y^3＋ceramics are investigated. Combining the lattice parameters and the distortion of crystal lattice, an alternation of substitution preference of Y^3＋ ion for the host cations in perovskite lattice is found. Owing to Y^3- ion entering the A site, the maximum dielectric constant is 5 627 for 1.25% Y^3＋-doped samples; when Y^3- ion is more than 1.25%, it tends to occupy the B site in perovskite lattice, causing a drop in the dielectric constant. Owing to the appearance of oxygen vacancy, the optimized dielectric loss is 0.004 for 1.25% Y^3＋-doped samples. The thermal stability of BSTS ceramics is significantly improved and the Curie temperature shifts to lower value with the amount of Y2O3 increased, making it a superior candidate for capacitor applications.展开更多
采用改进的溶胶凝胶燃烧法成功合成了Y^(3+)掺杂的多孔Na_(3)V_(2)(PO_(4))_(3)/C(记为NVP/C)复合材料,运用XRD、BET、SEM、HRTEM和电化学测试等手段对其进行结构表征和储钠性能测试。结果表明,半径较大的Y^(3+)取代NVP晶体结构中的部分...采用改进的溶胶凝胶燃烧法成功合成了Y^(3+)掺杂的多孔Na_(3)V_(2)(PO_(4))_(3)/C(记为NVP/C)复合材料,运用XRD、BET、SEM、HRTEM和电化学测试等手段对其进行结构表征和储钠性能测试。结果表明,半径较大的Y^(3+)取代NVP晶体结构中的部分V^(3+)导致晶格膨胀,扩大了Na^(+)的传输通道,加快了Na^(+)的迁移。在制备改性样品过程中,Y^(3+)与PO_(4)^(3-)发生反应,生成新的导电相YPO_(4),提高了复合材料的电子电导率。此外,Y^(3+)掺杂使得不规则多边形NVP颗粒球化并且尺寸略有减小。得益于适当的Y^(3+)掺杂量以及均匀的无定形碳包覆层和多孔结构,NVP/C-Y0.10样品具有优异的储钠性能,其在5 C高倍率下的首次放电比容量高达96.3 m A·h/g,经1000次循环后仍能保持82.2 m A·h/g的可逆容量。展开更多
Li1.02YxMn2-xO4（x = 0, 0. 005, 0.01, 0.02, 0.04, 0. 1） were prepared by solid state reaction method with raw materials Li2CO3, electrolytic MnO2 and Y2O3. Li1.02YxMn2-x O4 with different Y^3＋ contents have good cry...Li1.02YxMn2-xO4（x = 0, 0. 005, 0.01, 0.02, 0.04, 0. 1） were prepared by solid state reaction method with raw materials Li2CO3, electrolytic MnO2 and Y2O3. Li1.02YxMn2-x O4 with different Y^3＋ contents have good crystal structure, Y^3＋ doping makes the lattice parameter and crystal volume small. Cyclic vohammogram testing result shows that a small quantity of Y^3＋ doping has no influence on the Li^＋ deinsertion-insertion process, but Y^3＋ doping decreases the interacting force among Li^＋ , and then availably avoids the energy level splitting. The electrochemical property testing indicates that the initial discharge ca- pacity at x =0.02 is 117.2 mAh·g^-1 and remains 96.9% with 113.6 mAhg^-1 after 20 cycles, which explains that Y^3＋ doping effectively restricts Jahn-Teller effect and stabilizes the crystal structure. AC analysis shows that conductivity of the samples is clearly improved due to Y^3＋ doping.展开更多
基金Supported by Chinese Doctor Foundation of Ministry of Education of China (No20040056055)
文摘The structural and dielectric properties of Ba0.92Sr0.08Ti0.95Sn0.0503 （BSTS） ＋x（molar ratio, %） Y^3＋ceramics are investigated. Combining the lattice parameters and the distortion of crystal lattice, an alternation of substitution preference of Y^3＋ ion for the host cations in perovskite lattice is found. Owing to Y^3- ion entering the A site, the maximum dielectric constant is 5 627 for 1.25% Y^3＋-doped samples; when Y^3- ion is more than 1.25%, it tends to occupy the B site in perovskite lattice, causing a drop in the dielectric constant. Owing to the appearance of oxygen vacancy, the optimized dielectric loss is 0.004 for 1.25% Y^3＋-doped samples. The thermal stability of BSTS ceramics is significantly improved and the Curie temperature shifts to lower value with the amount of Y2O3 increased, making it a superior candidate for capacitor applications.
文摘采用改进的溶胶凝胶燃烧法成功合成了Y^(3+)掺杂的多孔Na_(3)V_(2)(PO_(4))_(3)/C(记为NVP/C)复合材料,运用XRD、BET、SEM、HRTEM和电化学测试等手段对其进行结构表征和储钠性能测试。结果表明,半径较大的Y^(3+)取代NVP晶体结构中的部分V^(3+)导致晶格膨胀,扩大了Na^(+)的传输通道,加快了Na^(+)的迁移。在制备改性样品过程中,Y^(3+)与PO_(4)^(3-)发生反应,生成新的导电相YPO_(4),提高了复合材料的电子电导率。此外,Y^(3+)掺杂使得不规则多边形NVP颗粒球化并且尺寸略有减小。得益于适当的Y^(3+)掺杂量以及均匀的无定形碳包覆层和多孔结构,NVP/C-Y0.10样品具有优异的储钠性能,其在5 C高倍率下的首次放电比容量高达96.3 m A·h/g,经1000次循环后仍能保持82.2 m A·h/g的可逆容量。
文摘采用高温固相反应法制备了Sr_(1-x)Ca_xSi_2O_2N_2∶Eu^(2+)系列荧光粉,研究Y^(3+)离子掺入对荧光粉发光性能的影响。对于Sr Si_2O_2N_2∶Eu^(2+),Y^(3+)离子掺入主要起到稳定Eu^(2+)价态的作用,避免Eu^(2+)氧化为Eu^(3+),从而提高Sr Si_2O_2N_2∶Eu^(2+)的发光性能。对于Ca Sr Si_2O_2N_2∶Eu^(2+),Y^(3+)离子掺入除了稳定Eu^(2+)价态作用外,还能有效减小Eu^(2+)取代Ca^(2+)后晶格膨胀引起的应力,提高Eu^(2+)在晶格中的溶解度。Sr_(1-x)Ca_xSi_2O_2N_2∶Eu^(2+)(x=0,0.15,0.3,0.6,0.75,0.95)系列荧光粉中随着Ca含量的增加,共掺Y^(3+)离子对样品发光强度的提高程度也随之增加(20%~80%)。
文摘Li1.02YxMn2-xO4（x = 0, 0. 005, 0.01, 0.02, 0.04, 0. 1） were prepared by solid state reaction method with raw materials Li2CO3, electrolytic MnO2 and Y2O3. Li1.02YxMn2-x O4 with different Y^3＋ contents have good crystal structure, Y^3＋ doping makes the lattice parameter and crystal volume small. Cyclic vohammogram testing result shows that a small quantity of Y^3＋ doping has no influence on the Li^＋ deinsertion-insertion process, but Y^3＋ doping decreases the interacting force among Li^＋ , and then availably avoids the energy level splitting. The electrochemical property testing indicates that the initial discharge ca- pacity at x =0.02 is 117.2 mAh·g^-1 and remains 96.9% with 113.6 mAhg^-1 after 20 cycles, which explains that Y^3＋ doping effectively restricts Jahn-Teller effect and stabilizes the crystal structure. AC analysis shows that conductivity of the samples is clearly improved due to Y^3＋ doping.
