EPR spectra of three new quaternary gadolinium complexes(I: [Gd(C6H5COO)2(NO3)(bipy)]2,Ⅱ: [Gd(m- CH3C6H4COO)2(NO3)(phen)]2 andⅢ: [Gd(p- CH3C6H4COO)(NO3)(phen)]2) with mixed anion ligands in polycrystalline powder...EPR spectra of three new quaternary gadolinium complexes(I: [Gd(C6H5COO)2(NO3)(bipy)]2,Ⅱ: [Gd(m- CH3C6H4COO)2(NO3)(phen)]2 andⅢ: [Gd(p- CH3C6H4COO)(NO3)(phen)]2) with mixed anion ligands in polycrystalline powders and solutions have been investigated at different temperatures and solvents.New behavior of EPR spectra of complexⅢ was first observed in polycrystalline powder at 77K and three types of EPR spectra for three complexes,symmetry resonance spectrum for the complexⅡ ,U spectrum for the complexⅢ ,and asymmetry resonance spectrum for the complex I.The relationship of EPR features between the crystal- field strength in the complexes and local symmetry around Gd(Ⅲ ) was discussed.The crystal- field parameters b20 and asymmetry parametersλ′ of the complexes I andⅢ were estimated.展开更多
以MoO_4^(2-)部分取代Li3Fe2(PO4)3中的PO_4^(3-),研究表明:加入的MoO_4^(2-)离子主要以固溶形式存在于Li3Fe2(PO4)3中,起到了显著改善其电化学性能的作用。其中,MoO_4^(2-)掺杂浓度为0.3的样品表现出最佳的电化学性能,其在0.5C倍率下...以MoO_4^(2-)部分取代Li3Fe2(PO4)3中的PO_4^(3-),研究表明:加入的MoO_4^(2-)离子主要以固溶形式存在于Li3Fe2(PO4)3中,起到了显著改善其电化学性能的作用。其中,MoO_4^(2-)掺杂浓度为0.3的样品表现出最佳的电化学性能,其在0.5C倍率下的首次放电容量为113.7 m Ah·g^(-1),这一数值比未掺杂的提高了20.7%;经过60次循环充放电,容量保持率为94%。将放电倍率从0.5C逐步增大至5C,再降至初始的0.5C,并在每个倍率循环10次,这一材料的最终放电容量可达首次0.5C的95%。这些优异的性能应归因于MoO_4^(2-)掺杂使材料的氧化还原能力增强,氧化还原电对的电势差减小,电池内部的电荷转移电阻减小,以及Li+扩散系数增加。展开更多
文摘EPR spectra of three new quaternary gadolinium complexes(I: [Gd(C6H5COO)2(NO3)(bipy)]2,Ⅱ: [Gd(m- CH3C6H4COO)2(NO3)(phen)]2 andⅢ: [Gd(p- CH3C6H4COO)(NO3)(phen)]2) with mixed anion ligands in polycrystalline powders and solutions have been investigated at different temperatures and solvents.New behavior of EPR spectra of complexⅢ was first observed in polycrystalline powder at 77K and three types of EPR spectra for three complexes,symmetry resonance spectrum for the complexⅡ ,U spectrum for the complexⅢ ,and asymmetry resonance spectrum for the complex I.The relationship of EPR features between the crystal- field strength in the complexes and local symmetry around Gd(Ⅲ ) was discussed.The crystal- field parameters b20 and asymmetry parametersλ′ of the complexes I andⅢ were estimated.
文摘以MoO_4^(2-)部分取代Li3Fe2(PO4)3中的PO_4^(3-),研究表明:加入的MoO_4^(2-)离子主要以固溶形式存在于Li3Fe2(PO4)3中,起到了显著改善其电化学性能的作用。其中,MoO_4^(2-)掺杂浓度为0.3的样品表现出最佳的电化学性能,其在0.5C倍率下的首次放电容量为113.7 m Ah·g^(-1),这一数值比未掺杂的提高了20.7%;经过60次循环充放电,容量保持率为94%。将放电倍率从0.5C逐步增大至5C,再降至初始的0.5C,并在每个倍率循环10次,这一材料的最终放电容量可达首次0.5C的95%。这些优异的性能应归因于MoO_4^(2-)掺杂使材料的氧化还原能力增强,氧化还原电对的电势差减小,电池内部的电荷转移电阻减小,以及Li+扩散系数增加。