纳米复合材料
材料科学
价(化学)
光谱学
电子能量损失谱
电极
分析化学(期刊)
离子
过渡金属
金属
无机化学
化学
纳米技术
透射电子显微镜
冶金
物理化学
催化作用
生物化学
物理
有机化学
色谱法
量子力学
作者
F. Cosandey,Jafar F. Al‐Sharab,Fadwa Badway,Glenn G. Amatucci,PA Stadelmann
标识
DOI:10.1017/s1431927607070183
摘要
A new type of positive electrode for Li-ion batteries has been developed recently based on FeF3/C and FeF2/C nanocomposites. The microstructural and redox evolution during discharge and recharge processes was followed by electron energy loss spectroscopy (EELS) to determine the valence state of Fe by measuring the Fe L3 line energy shift and from Fe L3/L2 line intensity ratios. In addition, transition metal fluorides were found to be electron beam sensitive, and the effect of beam exposure on EELS spectra was also investigated. The EELS results indicate that for both FeF3/C and FeF2/C nanocomposite systems, a complete reduction of iron to FeO is observed upon discharge to 1.5 V with the formation of a finer FeO/LiF subnanocomposite ( approximately 7 nm). Upon complete recharging to 4.5 V, EELS data reveal a reoxidation process to a Fe2+ state with the formation of a carbon metal fluoride nanocomposite related to the FeF2 structure.
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