Study on disordered structure and ionic diffusion in amorphous solids with non linear ultrasonic resonance

非线性超声共振研究非晶固体中的无序结构和离子扩散

• 批准号: 18540321
• 负责人: NAKAMURA Koichi
• 金额: $ 2.22万
• 依托单位: The University of Tokushima
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2006
• 资助国家: 日本
• 起止时间: 2006 至 2007
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-18540321/
• 关键词: Lithium ion secondary battery; Piezoelectric material; Mechanical milling; NMR; Electrical conductivity; LiCoO_2; LiNbO_2

lithium cobalt oxide has been used as a cathode material of lithium ionic rechargeable battery so far and advanced cathode material with higher charge/discharge properties has been expected. In this study, our aim is to obtain new insights into structural change and ionic diffusion in amorphous like lithium compounds by using fly-AIRS-Al milling (MM) method to control disorder of crystal structure. Electrical resistivity of milled lithium cobalt oxide is analyzed by a Delve model on the basis of a single ion hopping process The results indicate that in lithium cobalt oxide prepared by MM the moderate MM condition with short milling time stimulates the lithium ionic diffusion through the defects, while the excessive MM condition with long milling time degrades the lithium ionic diffusion becalm a large number of defects induced by excessive MM effectively cut off diffusion path fir migrating lithium ions In lithium cobalt oxide, it hind that the NMR line width of ^7Li NMR spectrum becom … More es broader with increasing milling time. The MM process changes magnetic state of cobalt which is primitively a low spin configuration in the CoO_6 octahedron so that the line broadening is ascribed to the magnetic width due to tee magnetic moment of cobalt induced by MM.On the other hand, piezoelectric material LiNbO_3 and LiTaO_3 milled fir several hours show the motional narrowing of ^7Li-NMR line width at mom temperature. This means that disordered crystal structure induces a fast ionic diffusion in these materials. From the NMR spectrum analysis by decomposing spectrum, it hind that several percent of lithium in the materials would diffuse with much lower activation energy of 0.3 eV than primitive activation energy of 1.6 eV in non-milled LiNbO_3 from the analysis by decomposing NMR spectrum, consisting of a narrow and broad spectrum.Echo decay time, T_2 of propagating wave in a SiO_2 particle was measured over the temperature range from room temperature to 500 K by two-pulse phonon echo technique. The values of T_2 are temperature independent so that SiO_2 might be a standard material to detect energy loss out of particles contacting other fine powder samples. Phonon echo of SiO_2 particles is strongly affected by mixing fine particles. Only 0.5 mol% of LiNbO_3 fine powder suppresses phonon echo intensity at room temperature in the air, because the wet fine powder prevent from vibration of SiO_2 particles. Phonon echo intensity increases due to dehydrating fine powder at 393K because it makes vibration of SiO_2 particles better. However, a large amount of mixed fine powder has suppressed phonon echo intensity even at high temperatures so that disappearance of phonon echo does not depend only on humidity. A further study will plan to study an origin of disappearance of phonon echo in mixed particle system. Less

到目前为止，氧化锂已被用作锂离子可充电电池的阴极材料，到目前为止，已经预计具有较高充电/放电性能的高级阴极材料。在这项研究中，我们的目的是通过使用Fly-Air-Al-Al铣削（MM）方法来控制晶体结构障碍，从而获得对无定形（如锂化合物）的结构变化和离子扩散的新见解。 Electrical resistant of milled lithium cobalt oxide is analyzed by a Delve model on the basis of a single ion hopping process The results indicate that in lithium cobalt oxide prepared by MM the moderate MM condition with short milling time stimulates the lithium ionic diffusion through the defects, while the excess MM condition with long milling time degrades the lithium ionic diffusion becalm a large number of defects通过过量的MM有效切断扩散路径FIR迁移的锂离子在氧化锂中的迁移，这阻碍了 ^7li NMR光谱的NMR线宽度变得更加宽。 MM过程会改变钴的磁状态，这是COO_6八面体中原始的低自旋构型，因此，由于Mm.on诱导的Tee磁矩，将线扩展分配给了磁性宽度，另一方面是mm.on，另一方面，压电材料linbo_3和Litao_3磨机的FIR几个小时显示了 ^7li-nmer not fir nequations not fir n ^7li n.li nmr nmr nmr nmr nmr at nmr nmr nmr nmr nmr nmr nmr。这意味着无序的晶体结构在这些材料中诱导了快速的离子扩散。从分解频谱的NMR频谱分析中，它阻碍了材料中的几个百分之几的锂会比非植物linbo_3中的1.6 eV的活化能低得多，而分解NMR光谱中的非植物linbo_3中的原始激活能量为1.6 eV，由狭窄和宽光谱的温度降低了狭窄的温度。通过两脉冲声子回声技术到500 k。 T_2的值独立于温度，因此SIO_2可能是从接触其他细粉末样品的颗粒中检测能量损失的标准材料。 SIO_2颗粒的声子回声会受到混合细颗粒的强烈影响。 linbo_3的仅0.5 mol％的细粉末在空气中的室温下抑制了声子回声强度，因为湿的细粉末可以防止SIO_2颗粒的振动。声子回声强度由于在393K处脱水的细粉而增加，因为它使SIO_2颗粒的振动更好。但是，大量的混合细粉即使在高温下也抑制了声子回声强度，因此声子Echo的消失不仅取决于湿度。一项进一步的研究将计划研究混合粒子系统中声子ECHO消失的起源。较少的

项目成果

リチウム化合物における結晶構造変化とイオンダイナミクス

锂化合物的晶体结构变化和离子动力学

• 发表时间: 2007
• 作者: K. Nakamura;et. al.;中村浩一他
• 通讯作者: 中村浩一他

Lithium ionic diffusion in lithium cobalt cxides prepared by mechanical milling

机械研磨制备的钴酸锂中的锂离子扩散

• 发表时间: 2007
• 作者: K. Nakamura;et. al.
• 通讯作者: et. al.

NMR Study on Lit Ionic Motion in Li_XV_20_5(0.4<x<1.4)

Li_XV_20_5(0.4<x<1.4)中锂离子运动的NMR研究

• 发表时间: 2008
• 期刊: Journal of the Physical Society of Japan 77
• 作者: D. Nishioka;et. al.
• 通讯作者: et. al.

Changes of the structure and electrical conductivity in LiCoO_2 prepared by mechanical milling

机械球磨制备LiCoO_2结构和电导率的变化

• 发表时间: 2007
• 作者: H. Hirano;et. al.
• 通讯作者: et. al.

NMR Study on Lit Ionic Motion in Li_xV_2O_5 (0.4<x<1.4)

Li_xV_2O_5 (0.4<x<1.4)中锂离子运动的NMR研究

• 发表时间: 2008
• 期刊: Journal of the Physical Society of Japan 77
• 作者: D. Nishioka;et. al.
• 通讯作者: et. al.