Engineering a homogeneous,stable and nitrogen-rich carbon coating on micro-/nano-sized hierarchical architectures still remains challenging due to the complex multiple procedures involved,the independent carbon and ni...Engineering a homogeneous,stable and nitrogen-rich carbon coating on micro-/nano-sized hierarchical architectures still remains challenging due to the complex multiple procedures involved,the independent carbon and nitrogen sources,and the possibility of structure collapse at elevated annealing temperatures.In this study,nitrogen-enriched carbon-coated flower-like bismuth sulfide(N–C@Bi_(2)S_(3))architectures were successfully synthesized by a facile hydrothermal method and post-heat treatment at mild temperatures.Due to the effective interaction between the catechol-/amine-groups and the inorganic materials,dopamine molecules were introduced and polymerized on the surface of the three-dimensional flowerlike Bi2S3 architectures,which were then converted into a homogeneous and thin nitrogen-enriched carbon layer with an average thickness of 5.0 nm.This thin layer played key roles in accelerating the fast electronic conduction,buffering the volume change of Bi_(2)S_(3)during cycling,and physically/chemically immobilizing the soluble polysulfide species.As expected,the as-prepared N–C@Bi_(2)S_(3)electrode offered a high reversible capacity of 1001.7 mA h g^(−1)(a high capacity retention of 78.5%)even after 224 cycles at 0.2 A g^(−1),an improved rate capability of 543 mA h g^(−1)at 2.5 A g^(−1)and a satisfactory capacity of 616.7 mA h g^(−1)at 1 A g^(−1)after 950 cycles.This feasible approach of engineering a homogeneous and thin nitrogen-enriched carbon layer can also be applied to a broad range of active materials with hierarchical structures for energy storage applications.展开更多
基金supported by the National Natural Science Foundation of China(No.51672146,21805157)the Natural Science Foundation of Shandong Province(ZR2018BEM011).
文摘Engineering a homogeneous,stable and nitrogen-rich carbon coating on micro-/nano-sized hierarchical architectures still remains challenging due to the complex multiple procedures involved,the independent carbon and nitrogen sources,and the possibility of structure collapse at elevated annealing temperatures.In this study,nitrogen-enriched carbon-coated flower-like bismuth sulfide(N–C@Bi_(2)S_(3))architectures were successfully synthesized by a facile hydrothermal method and post-heat treatment at mild temperatures.Due to the effective interaction between the catechol-/amine-groups and the inorganic materials,dopamine molecules were introduced and polymerized on the surface of the three-dimensional flowerlike Bi2S3 architectures,which were then converted into a homogeneous and thin nitrogen-enriched carbon layer with an average thickness of 5.0 nm.This thin layer played key roles in accelerating the fast electronic conduction,buffering the volume change of Bi_(2)S_(3)during cycling,and physically/chemically immobilizing the soluble polysulfide species.As expected,the as-prepared N–C@Bi_(2)S_(3)electrode offered a high reversible capacity of 1001.7 mA h g^(−1)(a high capacity retention of 78.5%)even after 224 cycles at 0.2 A g^(−1),an improved rate capability of 543 mA h g^(−1)at 2.5 A g^(−1)and a satisfactory capacity of 616.7 mA h g^(−1)at 1 A g^(−1)after 950 cycles.This feasible approach of engineering a homogeneous and thin nitrogen-enriched carbon layer can also be applied to a broad range of active materials with hierarchical structures for energy storage applications.
