Abstract
Resolving low sulfur reaction activity and severe polysulfide dissolution remains challenging in metal-sulfur batteries.Motivated by a theoretical prediction,herein,we strategically propose nitrogen-vacancy tantalum nitride(Ta3N5-x)impregnated inside the interconnected nanopores of nitrogen-decorated carbon matrix as a new electrocatalyst for regulating sulfur redox reactions in room-temperature sodium-sulfur batteries.Through a pore-constriction mechanism,the nitrogen vacancies are controllably constructed during the nucleation of Ta3N5-x.The defect manipulation on the local envi-ronment enables well-regulated Ta 5d-orbital energy level,not only modulating band structure toward enhanced intrinsic conductivity of Ta-based materials,but also promoting polysulfide stabilization and achieving bifunctional catalytic capability toward completely reversible polysulfide conversion.Moreover,the interconnected continuous Ta3N5-x-in-pore structure facilitates electron and sodium-ion transport and accommodates volume expansion of sulfur species while suppressing their shuttle behav-ior.Due to these attributes,the as-developed Ta3N5-x-based electrode achieves superior rate capability of 730 mAh g-1 at 3.35 A g-1,long-term cycling stability over 2000 cycles,and high areal capacity over 6 mAh cm-2 under high sulfur loading of 6.2 mg cm-2.This work not only presents a new sulfur electro-catalyst candidate for metal-sulfur batteries,but also sheds light on the controllable material design of defect structure in hopes of inspiring new ideas and directions for future research.
基金项目
University of Waterloo,Waterloo Institute for Nanotechnology,and Natural Sciences and Engineering Research Council of Canada(NSE()
Outstanding Youth Project of Guangdong Natural Science Foundation(2021B1515020051)
Department of Science and Technology of Guangdong Province(2019JC01L203)
Department of Science and Technology of Guangdong Province(2020B0909030004)
Natural Science Foundation of Ningxia(2023AAC01003)
Foundation of State Key Laboratory of High Efficiency Utilization of Coal and Green Chemical Engineering(2022-K79)
NETL
NSTL
维普
万方数据