Electrochemical Properties of Monoclinic NaMnO2

Monoclinic α- NaMnO 2 is re-investigated electrochemically as a positive electrode material for sodium ion batteries. About 0.85 Na can be deintercalated from NaMnO 2 and 0.8 Na be intercalated back during potentiostatical intermittent charge and discharge. Galvanostatical cycling between 2.0 V and 3.8 V gives 185 mAh/g discharge capacity for the first cycle at C/10 rate and 132 mAh/g remains after 20 cycles. Charge and discharge curves are significantly different indicating more hysteresis than is typical for lithium intercalation compounds. We also explain the remarkable difference between layered LiMnO 2 and NaMnO 2 upon alkali removal.