Sodium deficient transition metal oxides Na1/2Co1/3Ni1/3Mn1/3O2 as alternative electrode materials for lithium-ion batteries

Sodium-deficient transition metal oxides exhibit flexible layered structures which are able to adopt different layer stacking and symmetry. In this study, we provide new data on the structure and reversible lithium intercalation properties of oxides with composition Na1/2Co1/3Ni1/3Mn1/3O2. Novel properties of oxides determine their potential for using as alternative electrode materials for lithium-ion batteries. Between 700 and 800 degrees C, new layered oxide Na1/2Co1/3Ni1/3Mn1/3O2 with a P3-type of structure is obtained by a precursor-based method. A new structural feature of Na1/2Co1/3Ni1/3Mn1/3O2 as compared to well-known sodium stoichiometric oxides NaCo1/3Ni1/3Mn1/3O2 with an O-3-type of structure is the development of layer stacking ensuring prismatic site occupancy for Na+ ions with shared face on one side and shared edges on the other side with surrounding Co/Ni/MnO6 octahedra. The reversible lithium intercalation in Na1/2Co1/3Ni1/3Mn1/3O2 is demonstrated and discussed.