Distinctive Pseudocapacitive Behavior in Sodium Storage Mechanism of Molybdenum Dioxide Anodes

Abstract: Compared to cathode materials, anode part for sodium rechargeable batteries has showed relatively low progress in the research fields. To bring sodium rechargeable batteries to a next level, it is necessary to explore feasible anode materials as well as understand clearly the reaction mechanism during electrochemical cycling. We herein introduce mesoporous and bulk molybdenum dioxide materials as anode part for sodium rechargeable batteries, which show excellent sodium storage performances under ether based electrolyte conditions. Furthermore, pseudocapacitive behavior in sodium storage mechanism of molybdenum dioxide anodes were systematically demonstrated by using quantitative analysis of CV response along with synchrotron radiation based analyses, XPS, STEM and ab initio MD simulation. This comprehensive information on the electrochemical characterization as well as sodium storage mechanism of this transition metal oxide will provide practical strategy to the further advancement of anode materials for sodium rechargeable batteries.