12162-79-7Relevant articles and documents
Fernandez-Rodriguez, J. M.,Morales, J.,Tirado, J. L.
, p. 365 - 370 (1989)
Nanostructured lithium manganese oxide cathodes obtained by reducing lithium permanganate with methanol
Im,Manthiram
, p. A1001-A1014 (2002)
Reduction of lithium permanganate with methanol in acetonitrile and acetonitrile-water media has been investigated to obtain nanocrystalline lithium manganese oxides. The products have been characterized by wet-chemical analysis. Fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray diffraction, and transmission electron microscopy. The samples synthesized in acetonitrile medium consist of a considerable amount of organic residue even after firing at 250°C in vacuum, which could be lowered by introducing water into the synthesis and washing media (acetonitrile-water mixture). Additionally, introduction of lithium hydroxide into the synthesis medium helps to increase the lithium content and Li/Mn ratio in the product and thereby to improve the electrochemical performance. Optimum compositions synthesized in the acetonitrile-water exhibit capacities of >200 mAh/g with good cyclability and charge efficiency.
Dependence of the structures of manganese dioxides on their chemical properties
Wang, Wen-Lou,Wu, Minchang,Liu, Xianming
, p. 5 - 11 (2008/10/08)
Chemical properties of four manganese dioxides from different sources were investigated by means of a solvothermal method. The reactions of manganese dioxides with lithium chloride were carried out in 1-hexanol at 170°C. All manganese dioxides used in this work consist of two kinds of building blocks, i.e., the 2 × 1 tunnel and the 1 × 1 tunnel. The tunnel structure strongly affects chemical behaviors: manganese dioxide with the 1 × 1 tunnel results in the formation of the spinel lithium manganese oxide; a novel structural LixMnO2 can be made from manganese dioxide with the 2 × 1 tunnel. The concentration of each product is sensitive to the content of the corresponding building block in a precursor. On the other hand, the microtwinning and the surface reaction may also affect the formation of the products. Both products were formed by different paths. Insertion of lithium ions into the 2 × 1 tunnels was observed; however, insertion into the 1 × 1 tunnels was not detected. The difference between them may he explained by the space and the energy of the building blocks.
