Structure - Electrode Activity Relationship in Triphyllite - Related Compounds

闪石相关化合物的结构-电极活性关系

基本信息

批准号：
16350108
负责人：
YAMADA Atsuo
金额：
$ 10.18万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2006
项目状态：
已结题

项目摘要

A series of synthetic (Mn_yFe_<1-y_)PO_4(y<0.8) phases were obtained by chemical oxidation of crystallized isotypic Li(Mn_yFe_<1-y>)PO_4 under optimized conditions. All samples exhibit antiferromagnetism but the decrease in Neel temperature is more than 7 times larger in (Mn_yFe_<1-y>)PO_4 than in Li(Mn_yFe_<1-y>)PO_4. This was discussed in terms of the asymmetric superexchange interaction by an unusual synergetic effect of Jahn-Teller distortion and edge-shared interconnection with PO_4 tetrahedra.We provide firm experimental evidence that Li_xFePO_4 at room temperature can be described as a mixture of the Fe^<3+>/Fe^<2+> mixed-valent intermediate Li_αFePO_4 and Li_<1-β>FePO_4 phases with surprisingly large values of α and β. Using powder neutron diffraction, the site occupancy numbers for lithium in each phase were refined to be α=0.05 and 1-β=0.89. The corresponding solid solution ranges outside the miscibility gap (0<x<α, 1-β<x<1) were detected by the anomaly in the configurational … More entropy and also by the deviation of the open-circuit voltage from the constant equilibrium potential. These findings encourage further improvement of this important class of compounds at ambient temperatures.Rietveld analysis for the powder neutron diffraction profile for LiFePO_4 was performed. Tensor elements of the unisotropic thermal factor showed the principal axis of the lithium vibration is toward the face shared vacant tetrahedral space. This is consistent with the theoretical prediction ; lithium ions diffuse along curved one-dementional chain along b-axis. Impact of temperature on the phase diagram of LixFePO_4 with > 200nm particle size was slight under the unmixing line around 200 C. While the reduction in particle size down to <100 nm seems to have significant effect to the room temperature miscibility gap. The thermodynamic concepts for the extended solution in smaller particles are discussed, followed by a very high rate capability observed for the small spherical particles <80nm. Less

在优化条件下，通过结晶的同种型LI（Mn_yfe_ <1-y>）的化学氧化获得了一系列合成（Mn_yfe_ <1-y_）PO_4（y <0.8）阶段。所有样品均表现出抗铁磁性，但NEEL温度的降低（Mn_yfe_ <1-Y>）PO_4的降低是LI（Mn_yfe_ <1-y>）PO_4的7倍以上。通过不对称的超级交流的相互作用来讨论这一点，这是通过Jahn-Teller失真和与PO_4 Tetrahedra的边缘互连的异常协同效应。我们提供了坚定的实验证据，表明li_xfepo_4在室温下可以描述为Fe^<3+>/fe^<3+>/fe^<3+>/fe^<2 <2+>/fe^<2> <2+>/fe^<2 <2> <2 <2> <2 <2> <2 <2> <2 <2> <2> Li_ <1-β> FEPO_4相具有惊人的α和β值。使用粉末中子衍射，将每个相位的锂的位点占用数进行完善为α= 0.05和1-β= 0.89。相应的固体溶液范围范围范围（0 <x <α，1-β<x <1）在构型中的异常中被检测到……更多的熵，也是通过从恒定等效电位出发的开路电压出发的。这些发现鼓励在环境温度下进一步改善这种重要的化合物。进行LIFEPO_4的粉末中子衍射概况分析。 Unisropic热因子的张量元件显示锂振动的主要轴是朝向脸部共享空置的四面体空间。这与理论预测一致。锂离子沿B轴沿弯曲的一链链扩散。温度对200nm粒径的LIXFEPO_4相图的影响在200 C左右的未成线下方略有略有粘合线的影响，而粒度降低至<100 nm的降低似乎对室温混杂性差距产生了显着影响。讨论了较小颗粒中扩展溶液的热力学概念，然后观察到<80nm的小球粒子的速率能力很高。较少的

项目成果

期刊论文数量（25）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Electrochemical, magnetic, and structural investigation of the Li_<1-x>(Mn_yFe_<1-y>)PO_4 olivine phases

Li_<1-x>(Mn_yFe_<1-y>)PO_4橄榄石相的电化学、磁性和结构研究

DOI：
发表时间：
2006
期刊：
Chem. Mater. 18
影响因子：
0
作者：
A.Yamada;Y.Takei;et al.
通讯作者：
et al.

Magnetic properties of Li(Mn_yFe_<l-y>)PO_4 and its delithiated phases

Li(Mn_yFe_<l-y>)PO_4及其脱锂相的磁性

DOI：
发表时间：
2005
期刊：
Appl. Phys. Lett 87
影响因子：
0
作者：
A.Yamada;Y.Takei;et al.
通讯作者：
et al.

電池革新が拓く次世代電源

电池创新引领的下一代电源

DOI：
发表时间：
2006
期刊：
影响因子：
0
作者：
N.Arimitsu;A.Nakajima;K.Katsumata;T.Shiota;N.Yoshida;T.Watanabe;Y.Kameshima;K.Okada;M.K.I.Senevirathna;G.R.A.Kumara;G.R.A.Kumara;B.Onwona-Agyeman;辰巳国昭他
通讯作者：
辰巳国昭他

Magnetic properties of Li(Mn_yFe_<i-y>)PO4 and its delithiated phases

Li(Mn_yFe_<i-y>)PO4及其脱锂相的磁性