Transition metal oxysalts are evaluated as conversion electrode material. Anhydrous iron oxalate is investigated and a comparison with manganese carbonate is carried out to envisage the possible extension of these studies to a vast number of transition metal oxysalts. The dehydration process is studied by thermal analysis to prepare the anhydrous oxysalts. Both manganese carbonate and iron oxalate are interesting candidates for the active material of the negative electrode of lithium-ion batteries. A higher reversible capacity and lower irreversible capacity are observed for the oxalate compound. The reversible capacity cannot be exclusively ascribed to redox processes involving iron. The low temperature synthesis of these materials makes them an inexpensive option for this purpose.