Synthesis, ion exchange and electrochemical properties of lamellar phyllomanganates of the birnessite group

Synthesis of various X-birnessites was performed using the ion exchange properties of the sodium birnessite Na0.32MnO2,yH2O. Their structural and electro-chemical characteristics are investigated and discussed in comparison with previous data obtained for some compounds and in relation with mechanism invoked for Li electrochemical insertion into sol-gel and chemical birnessites. Two main groups of materials are obtained with a monoclinic or hexagonal structure depending on the kind of inserted cation.