First-principles computational studies on layered Na2Mn3O7 as a high-rate cathode material for sodium ion batteries

By first-principles computations, we propose Na2Mn3O7 as a high-rate cathode material for sodium ion batteries. Na2Mn3O7 has a voltage window of 3.6-3.1 V and a theoretical reversible capacity of 124 mA h g(-1). Na2Mn3O7 is a semiconductor and turns metallic after Na extraction; moreover, the calculated Na migration barrier in Na2Mn3O7 is 0.18 eV, ensuring ideal conductivity and rate capability.