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Polymorphism in Li2MSiO4 ( M = Fe, Mn): A Variable Temperature Diffraction Study
DOI:10.1002/zaac.201400081.png)
摘要
En 中文
Lithium transition metal silicates, Li2MSiO4 (M = Fe, Mn, Co), have attracted much interest as positive electrodes for Li-ion batteries due to their high theoretical capacities and their rich crystal chemistry. Low () and high () temperature forms of these tetrahedral structures differ in the ordering/distribution of cations within tetrahedral sites of an hcp based packing of oxygen. We have carried out VT powder neutron and X-ray diffraction on Li2MSiO4 (M = Fe, Mn) to characterize the rich polymorphism observed across the Li2MSiO4 (M = Fe, Mn) system as a function of temperature. For Li2FeSiO4 below 500 degrees C a (II) phase was observed with slight Li/Fe disorder. Above this temperature there was a sluggish transition to the (s) phase, which was observed up to ca. 820 degrees C, with the (II) polymorph seen at highest temperatures. Excellent agreement with phases obtained by quenching was observed, except that the phases exhibit a statistical distribution of Li/Fe, in contrast to the well-ordered structures of quenched phases. The Li2MnSiO4 polymorphism is less complex, the (II) phase is stable from room temperature to 750 degrees C, at which temperature it transforms to the structure with disordered Li/Mn.
Keyword:
Lithium
Transition metals
Silicates
Temperature diffraction
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期刊
Z
IF:
1.1
论文数:
193
被引数:
7.3K
机构
引用论文
Beyond one-electron reaction in Li cathode materials:: Designing Li2MnxFe1-xSiO4超越Li阴极材料中的单电子反应:: 设计Li2MnxFe1-xSiO4
Crystal Structure, Energetics, And Electrochemistry of Li2FeSiO4 Polymorphs from First Principles Calculations通过第一性原理计算得出的Li2FeSiO4多晶型物的晶体结构,能量学和电化学
Structure and Lithium Transport Pathways in Li2FeSiO4 Cathodes for Lithium Batteries锂电池正极Li2FeSiO4的结构和锂传输途径
Synthesis and electrochemical performance of Li2CoSiO4 as cathode material for lithium ion batteries锂离子电池正极材料Li2CoSiO4的合成及电化学性能研究

