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 Mo3N2 nanowires (Meso-Mo3N2-NWs). The sodium-ion storage mechanism of Mo3N2 is systematically investigated through in-situ XRD, ex-situ experimental characterizations and detailed kinetics analysis. Briefly, the Mo3N2 undergoes a surface pseudocapacitive redox charge storage process. Benefiting from the rapid surface redox reaction, the Meso-Mo3N2-NWs anode delivers high specific capacity (282 mAh g(-1) at 0.1 A g(-1)), excellent rate capability (87 mAh g(-1) at 16 A g(-1)) and long cycling stability (a capacity retention of 78.6% after 800 cycles at 1 A g(-1)). 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. (C) 2020 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.