Surface pseudocapacitance of mesoporous Mo3N2 nanowire anode toward reversible high-rate sodium-ion storage

Sodium-ion storage devices are highly desirable for large-scale energy storage applications owing to the wide availability of sodium resources and low cost. Transition metal nitrides(TMNs) are promising anode materials for sodium-ion storage, while their detailed reaction mechanism remains unexplored. Herein,we synthesize the mesoporous MoNnanowires(Meso- MoN-NWs). The sodium-ion storage mechanism of MoNis systematically investigated through in-situ XRD, ex-situ experimental characterizations and detailed kinetics analysis. Briefly, the MoNundergoes a surface pseudocapacitive redox charge storage process. Benefiting from the rapid surface redox reaction, the Meso- MoN-NWs anode delivers high specific capacity(282 m Ah gat 0.1 A g), excellent rate capability(87 m Ah gat 16 A g) and long cycling stability(a capacity retention of 78.6% after 800 cycles at 1 A g). The present work highlights that the surface pseudocapacitive sodium-ion storage mechanism enables to overcome the sluggish sodium-ion diffusion process, which opens a new direction to design and synthesize high-rate sodiumion storage materials.