کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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1331871 | 979020 | 2006 | 10 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Synthesis and phase transition of Li–Mn–O spinels with high Li/Mn ratio by thermo-decomposition of LiMnC2O4(Ac) Synthesis and phase transition of Li–Mn–O spinels with high Li/Mn ratio by thermo-decomposition of LiMnC2O4(Ac)](/preview/png/1331871.png)
LiMnC2O4(Ac) precursor in which Li+ and Mn2+ were amalgamated in one molecule was prepared by solid-state reaction at room-temperature using manganese acetate, lithium hydroxide and oxalic acid as raw materials. By thermo-decomposition of LiMnC2O4(Ac) at various temperatures, a series of Li1+y[Mn2−xLix]16dO4 spinels were prepared with Li2MnO3 as impurities. The structure and phase transition of these spinels were investigated by XRD, TG/DTA, average oxidation state of Mn and cyclic voltammeric techniques. Results revealed that the Li–Mn–O spinels with high Li/Mn ratio were unstable at high temperature, and the phase transition was associated with the transfer of Li+ from octahedral 16c sites to 16d sites. With the sintering temperature increasing from 450 to 850 °C, the phase structure varied from lithiated-spinel Li2Mn2O4 to Li4Mn5O12-like to LiMn2O4-like and finally to rock-salt LiMnO2-like. A way of determining x with average oxidation state of Mn and the content of Li2MnO3 was also demonstrated.
Function of the average oxidation state of Mn with the fraction of Li+ in the octahedral 16d sites (x∼n) and octahedral 16c sites (y∼n) for Li1+y[Mn2−xLix]16dO4 spinels (Li:Mn=1, at the case of 2x+y=12x+y=1).Figure optionsDownload as PowerPoint slide
Journal: Journal of Solid State Chemistry - Volume 179, Issue 4, April 2006, Pages 1100–1109