Preparation, characterization and electrochemical performance of γ-MnO2 and LiMn2O4 as cathodes for lithium batteries

Abstract

Abstract. The spinel LiMn204 is a very promising cathode material with economical and environmental advantages. LiMn204 materials have been synthesized by solid state method using 7-MNO2 as manganese source, and Li2CO 3 or LiNO3 as Li sources. T-MnO2 is a commercial battery grade electrolytic manganese dioxide (TOSOH-Hellas GH-S) and LiMn204 samples were synthesized at a calcinations temperature up to 800 ~ y-MnO2 and LiMn204 samples were characterized by X-ray diffraction, thermal and electrochemical measurements. X-ray powder diffraction of as prepared LiMn204 showed a well-defined highly pure spinel single phase. The electrochemical performance of LiMn204 and its starting material y-MnO2 was evaluated through cyclic voltammetry, galvanostatic (constant current charge-discharge cycling) The electrochemical properties in terms of cycle performance were also discussed.7-MnO2 showed fairly high initial capacity of about 200 mAhg -1 but poor cycle performance.LiMn204 samples showed fairly low initial capacity but good cycle performance.

Thermal stabilization of tin- and cobalt-doped manganese dioxide

“…The third weight loss (ca 3.1%) observed at 800°C corresponds to the transformation of Mn 2 O 3 to Mn 3 O 4 occurring with a release of oxygen. Thermal decomposition reactions of the starting α-MnO 2 are in good agreement with the phenomena given by [23,24] 2 MnO 2 ! Mn 2 O 3 1=2O 2 ; ð1Þ…”