A new electrode material for rechargeable sodium batteries: P2-type Na2/3[Mg0.28Mn0.72]O2 with anomalously high reversible capacity

Abstract
P2-type Na2/3[Mg0.28Mn0.72]O2 is prepared and electrode performance in Na cells is first provided. The sample surprisingly delivers a large reversible capacity (220 mA h g−1) even though electrochemically inactive magnesium ions are enriched in the host structure. This new electrode material is potentially utilized for rechargeable batteries made from only earth-abundant elements.