The rapid expansion of the photovoltaic industry has generated heavily oxidized waste silicon(wSi),which hinders efficient recycling owing to its small particle size and uncontrolled surface oxidation.This study intro...The rapid expansion of the photovoltaic industry has generated heavily oxidized waste silicon(wSi),which hinders efficient recycling owing to its small particle size and uncontrolled surface oxidation.This study introduces a molten salt electrochemical strategy for converting photovoltaic wSi into NiSi_(2)-silicon nanorods(NiSi_(2)-SiNRs)as high-performance anode materials for lithium-ion batteries.A stable oxidized passivation layer is formed on the wSi surface via controlled oxidation,and further in situ generated highly active NiSi_(2) droplets.The molten salt electric field modulates the surface energy of silicon,while particle integration drives localized directional growth,enabling the self-assembly of NiSi_(2)-SiNRs composites.These NiSi_(2)-SiNRs anodes exhibit rapid ion transport and effective strain buffering.The high aspect ratio of SiNRs and the presence of retained NiSi_(2) facilitate both longitudinal and transverse Li^(+) diffusion.Owing to their robust structural design,the NiSi_(2)-SiNRs anode achieves an excellent initial Coulombic efficiency of 91.61%and retains 72.99%of its capacity after 800 cycles at 2 A·g^(−1).This study establishes a model system for investigating silicide/silicon interfaces in molten salt electrochemical synthesis and provides an effective strategy for upcycling photovoltaic wSi into high-performance lithium-ion battery anodes.展开更多
Sodium-ion batteries(SIBs) are promising electrochemical energy storage systems as lithium-ion batteries by virtue of their similar chemical properties and natural abundance and availability.However,the ionic radius o...Sodium-ion batteries(SIBs) are promising electrochemical energy storage systems as lithium-ion batteries by virtue of their similar chemical properties and natural abundance and availability.However,the ionic radius of Na^(+)is larger than that of Li^(+),leading to challenges in its insertion/extraction at anode side.As a class of anode materials,phosphorus allotropes(PAs,red,and black) and metal phosphides(MPs) have shown great prospects because of high theoretical gravimetric/volumetric capacity,high carrier mobility,and suitable redox potential.In this review,recent developments in the studies of PAs and MPs with particular emphasis on understanding sodium storage mechanisms,developing novel synthesis strategies,and performance validations have been manifested valuable solutions to address these challenges.We begin with the introduction and classification of the macroscopic sodiation mechanisms of PAs and MPs,and the various fabrication strategies of PAs and MPs are comprehensively summarized in second section.The third section thoroughly reviews the progresses on PAs and MPs-based advanced materials for their application in SIBs.Finally,we also discuss the significant challenges and outline a roadmap for future research directions.展开更多
Well ordered porous anodic alumina (PAA) film was prepared on pure Al substrate using sulfuric/oxalic acid mixture as electrolyte with different ratios, the best regular PAA film with an average diameter of 45 nm was ...Well ordered porous anodic alumina (PAA) film was prepared on pure Al substrate using sulfuric/oxalic acid mixture as electrolyte with different ratios, the best regular PAA film with an average diameter of 45 nm was obtained using 1∶1 sulfuric/oxalic (molar concentration) mixed acid at 26 V. Addition of oxalic acid into sulfuric acid electrolyte resulted in the increase of anodizing current density, indicating a faster formation rate of PAA film. In 1∶1 sulfuric/oxalic acid electrolyte, the current density was the biggest, which illustrated that the formed barrier layer was the thinnest. Besides, addition of oxalic acid increased the stress of oxide film, accordingly changed the self-organized process of PAA film. XPS results indicate that the PAA film is mainly composed of amorphous alumina independent of oxalic acid addition.展开更多
基金supported by the Yunnan Province Basic Research General Program,China(No.202201BE070001-002)the Major Science and Technology Projects in Yunnan Province,China(No.202402AF 080005).
文摘The rapid expansion of the photovoltaic industry has generated heavily oxidized waste silicon(wSi),which hinders efficient recycling owing to its small particle size and uncontrolled surface oxidation.This study introduces a molten salt electrochemical strategy for converting photovoltaic wSi into NiSi_(2)-silicon nanorods(NiSi_(2)-SiNRs)as high-performance anode materials for lithium-ion batteries.A stable oxidized passivation layer is formed on the wSi surface via controlled oxidation,and further in situ generated highly active NiSi_(2) droplets.The molten salt electric field modulates the surface energy of silicon,while particle integration drives localized directional growth,enabling the self-assembly of NiSi_(2)-SiNRs composites.These NiSi_(2)-SiNRs anodes exhibit rapid ion transport and effective strain buffering.The high aspect ratio of SiNRs and the presence of retained NiSi_(2) facilitate both longitudinal and transverse Li^(+) diffusion.Owing to their robust structural design,the NiSi_(2)-SiNRs anode achieves an excellent initial Coulombic efficiency of 91.61%and retains 72.99%of its capacity after 800 cycles at 2 A·g^(−1).This study establishes a model system for investigating silicide/silicon interfaces in molten salt electrochemical synthesis and provides an effective strategy for upcycling photovoltaic wSi into high-performance lithium-ion battery anodes.
基金financially supported by the Natural Science Foundation of China(Nos.22208214,22005190,and 21938005)the Science&Technology Commission of Shanghai Municipality(Nos.20QB1405700,and 19DZ1205500)Zhejiang Key Research and Development Program(No.2020C01128)
文摘Sodium-ion batteries(SIBs) are promising electrochemical energy storage systems as lithium-ion batteries by virtue of their similar chemical properties and natural abundance and availability.However,the ionic radius of Na^(+)is larger than that of Li^(+),leading to challenges in its insertion/extraction at anode side.As a class of anode materials,phosphorus allotropes(PAs,red,and black) and metal phosphides(MPs) have shown great prospects because of high theoretical gravimetric/volumetric capacity,high carrier mobility,and suitable redox potential.In this review,recent developments in the studies of PAs and MPs with particular emphasis on understanding sodium storage mechanisms,developing novel synthesis strategies,and performance validations have been manifested valuable solutions to address these challenges.We begin with the introduction and classification of the macroscopic sodiation mechanisms of PAs and MPs,and the various fabrication strategies of PAs and MPs are comprehensively summarized in second section.The third section thoroughly reviews the progresses on PAs and MPs-based advanced materials for their application in SIBs.Finally,we also discuss the significant challenges and outline a roadmap for future research directions.
文摘Well ordered porous anodic alumina (PAA) film was prepared on pure Al substrate using sulfuric/oxalic acid mixture as electrolyte with different ratios, the best regular PAA film with an average diameter of 45 nm was obtained using 1∶1 sulfuric/oxalic (molar concentration) mixed acid at 26 V. Addition of oxalic acid into sulfuric acid electrolyte resulted in the increase of anodizing current density, indicating a faster formation rate of PAA film. In 1∶1 sulfuric/oxalic acid electrolyte, the current density was the biggest, which illustrated that the formed barrier layer was the thinnest. Besides, addition of oxalic acid increased the stress of oxide film, accordingly changed the self-organized process of PAA film. XPS results indicate that the PAA film is mainly composed of amorphous alumina independent of oxalic acid addition.
