Binary alloys have garnered significant attention for the development of the sodium-ion battery due to their ability to combine the advantages of single-phase alloys.However,these materials often demonstrate limited e...Binary alloys have garnered significant attention for the development of the sodium-ion battery due to their ability to combine the advantages of single-phase alloys.However,these materials often demonstrate limited electrochemical performance,and the relationship between their crystallization states and their sodium storage properties remains poorly understood.Here,we synthesize Bi-Sn binary alloys with various compositions via phase-separation metallurgy to explore the sodium storage properties of different crystalline structures.The results indicate that hypo-and hyper-eutectic Bi-Sn alloys readily form a“dendritic”primary phase at the non-eutectic interface,which aggravates structural degradation and increases internal resistance.In contrast,Bi-Sn alloys with optimized eutectic interfaces effectively control dendritic growth and reduce defects,resulting in enhanced microstructural stability and superior electrochemical performance.As results,the eutectic p-Bi_(57)Sn_(43)@C anode achieves a record-high specific capacity of 470.3 mAh g^(-1) at 1 C and exhibits remarkable long-term cycling stability,retaining 95.2%of its capacity after 1000 cycles at 20 C.The defect-free eutectic concept presented here establishes a valuable foundation for future studies of binary and polycrystalline eutectic alloys in electrochemical applications.展开更多
基金supported by the National Natural Science Foundation of China(22309056,52002297 and U2004210)Knowledge Innovation Project of Wuhan City(2022010801010303)+3 种基金National Key R&D Program of China(2022YF2404800)Key R&D Projects of Hubei Province(2022BCA061)Application Foundation Frontier Project of Wuhan Science and Technology Program(2020010601012199)Basic Research Program of Shenzhen Municipal Science and Technology Innovation Committee(JCYJ20210324141613032)。
文摘Binary alloys have garnered significant attention for the development of the sodium-ion battery due to their ability to combine the advantages of single-phase alloys.However,these materials often demonstrate limited electrochemical performance,and the relationship between their crystallization states and their sodium storage properties remains poorly understood.Here,we synthesize Bi-Sn binary alloys with various compositions via phase-separation metallurgy to explore the sodium storage properties of different crystalline structures.The results indicate that hypo-and hyper-eutectic Bi-Sn alloys readily form a“dendritic”primary phase at the non-eutectic interface,which aggravates structural degradation and increases internal resistance.In contrast,Bi-Sn alloys with optimized eutectic interfaces effectively control dendritic growth and reduce defects,resulting in enhanced microstructural stability and superior electrochemical performance.As results,the eutectic p-Bi_(57)Sn_(43)@C anode achieves a record-high specific capacity of 470.3 mAh g^(-1) at 1 C and exhibits remarkable long-term cycling stability,retaining 95.2%of its capacity after 1000 cycles at 20 C.The defect-free eutectic concept presented here establishes a valuable foundation for future studies of binary and polycrystalline eutectic alloys in electrochemical applications.
