Preparation and electrochemical performance of composite oxide of alpha manganes

2019-09-13 05:53:33

composite alpha manganese oxide spinel

责任者: Komaba, Shinichi;Sasaki, Tomoya;Kumagai, Naoaki 单位: Dept. Frontier Mat. and Funct. Eng., Graduate School of Engineering, Iwate University, Morioka, Iwate 020-8551, Japan 来源出处: Electrochimica Acta,2005,50(11):2297-2305 摘要: Nano-sized composite powder which consisted of two manganese-based oxides, alpha manganese dioxide (α-MnO2) and spinel Li-Mn-O, was successfully formed by intergrowth of the spinel phase inside α-MnO 2. This composite oxide was synthesized by precipitation and heat treatment in air; α-manganese dioxide powder was firstly prepared by oxidative precipitation of Mn(II) with K2S2O8 in an aqueous solution, and then a mixture of the obtained manganese oxide powder and LiOH methanol solution was heat-treated in air. Electron microscopy and diffraction observations confirmed that the manganese oxide composite consisted of nano-sized grains of the spinel LiMn2O4 and α-MnO2 phases. It was found that this α-MnO 2/spinel LiMn2O4 composite electrode exhibited highly reversible lithium insertion compared to the pristine α-MnO 2 and conventional LiMn2O4, that is, the composite demonstrated high discharge capacity of 148 mAh g-1 as a cathode material of lithium cells in the potential range of 2.5-4.3 V with no significant capacity fading. It was thought that the intimately mixing of two oxides on a nanometer scale helped to maintain structural integrity on charge-discharge cycling, which leads to excellent capacity retention for both of the spinel and alpha-type manganese oxide. © 2004 Elsevier Ltd. All rights reserved. 关键词: Electrochemistry;Manganese compounds;Lithium compounds;Composite materials;Nanostructured materials;Synthesis (chemical);Precipitation (chemical);Heat treatment;Electrochemical electrodes;Lithium batteries;Intercalation compounds;LiMn2O4;7alpha;-MnO2;Lithium intercalation;Nanocomposites