In Situ Preparation of Sandwich MoO3/C Hybrid Nanostructures for High-Rate and Ultralong-Life Supercapacitors

This work presents a design of sandwich MoO3/C hybrid nanostructure via calcination of the dodecylamine-intercalated layered -MoO3, leading to the in situ production of the interlayered graphene layer. The sample with a high degree of graphitization of graphene layer and more interlayered void region exhibits the most outstanding energy storage performance. The obtained material is capable of delivering a high specific capacitance of 331 F g(-1) at a current density of 1 A g(-1) and retained 71% capacitance at 10 A g(-1). In addition, nearly no discharge capacity decay between 1000 and 10 000 continuous charge-discharge cycles is observed at a high current density of 10 A g(-1), indicating an excellent specific capacitance retention ability. The exceptional rate capability endows the electrode with a high energy density of 41.2 W h kg(-1) and a high power density of 12.0 kW kg(-1) simultaneously. The excellent performance is attributed to the sandwich hybrid nanostructure of MoO3/C with broad ion diffusion pathway, low charge-transfer resistance, and robust structure at high current density for long-time cycling. The present work provides an insight into the fabrication of novel electrode materials with both enhanced rate capability and cyclability for potential use in supercapacitor and other energy storage devices.