Cobalt Additives Influence on Phase Composition and Defect Structure of Manganese Dioxide Prepared from Fluorine Containing Electrolytes

Manganese dioxide samples were prepared from fluorine containing electrolytes with additives of $Co^{2+}$ ions. Atomic absorption spectroscopy, thermogravimetric analysis, X-ray diffraction, scanning electron microscopy with energy dispersive X-ray analysis were the methods of the samples characterisation. Manganese dioxide at the presence of cobalt forms nanosized ramsdellite structure crystallites of mostly needle-like morphology with significant content of hydroxide groups. The main phase state in manganese dioxide samples obtained at the presence of cobalt is $γ-MnO_{2}$ with ramsdellite structure and low content of intergrowth defects. The sample doped both with lithium and cobalt can be indexed to a hollandite-type structure (tetragonal; space group I4/m) of $α-MnO_{2}$.