Analytical Sciences

Abstract − Analytical Sciences, 21(7), 861 (2005).

Valence Determination of Manganese in Battery Cathode Materials by High-Resolution Mn Kα1 Spectra
Tokuzo KONISHI,*1 Toshio TSUBATA,*2 Masaoki OKU,*3 Yanko M. TODOROV,*4 and Masaki YOSHIO*4
*1 Analysis and Simulation Center, Asahi Kasei Corporation, 2-1 Samejima, Fuji 416-8501, Japan
*2 Battery Materials Business Development Dept., Asahi Kasei EMD Corporation, 2-1 Samejima, Fuji 416-8501, Japan
*3 Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
*4 Department of Applied Chemistry, Saga University, Saga 840-8502, Japan
High-resolution the Mn Kα1 X-ray fluorescence spectra (HRXRF) were measured for a variety of manganese compounds, the oxidation number (valence) of which was from II to VII. Plots of the valence against the full width at half maximum (FWHM) and the chemical shift of the Kα1 X-ray fluorescence spectra give a curve and a liniar relation, respectively. The coefficient of correlation (R2) for the latter plot was 0.989 between valency II and VII. More excellent linearlity from III to IV was obtained with R2 = 0.995, which enabled us to determine the oxidation number of manganese atom in a nickel ion doped spinel structure, LiMn2O4 (LiNixMn2-xO4, with 0.2 < x < 0.42). From the valence of manganese ion obtained from HRXRF, the oxidation number of nickel ion is concluded to be divalent.