Lithium metal is one of the most promising anodes to develop high energy density and safe energy storage devices due to its highest theoretical capacity(3860 mAh·g^(−1))and lowest electrochemical potential,demons...Lithium metal is one of the most promising anodes to develop high energy density and safe energy storage devices due to its highest theoretical capacity(3860 mAh·g^(−1))and lowest electrochemical potential,demonstrating great potential to fulfill unprecedented demand from electronic gadgets,electric vehicles,and grid storage.Despite these good merits,lithium metal suffers from low Coulombic efficiency and dendritic growth,leading to internal short-circuiting of the cell and raising safety concerns about employing lithium metal as an anode.Recently,lithium-tin(Li-Sn)alloys,among other lithium alloys,have emerged as a potential alternative to lithium metal to efficiently suppress the lithium dendrite formation and reduce interfacial resistance for safer and longer-lasting lithium batteries.Accordingly,this work first reviews the fundamentals of Li-Sn alloys,and critically analyzes the failure mechanisms of pristine Li-metal anode and how Li-Sn alloys could overcome those challenges.The subsequent section examines various strategies to synthesize Li-Sn bulk and protection film alloys,followed by an evaluation of symmetric cell performance.Furthermore,the comparative electrochemical performance of full cells against different cathodes and solid electrolytes provides an overview of the present research.Subsequently,advanced characterization techniques were discussed to visualize lithium dendrites directly and quantify the mechanical performance of Li-Sn alloys.Last but not the least,the state-of-the-art progress of applying M-Sn(M=Na and Mg)beyond lithium batteries was summarized.In closing,this work identifies the critical challenges and provides future perspectives on Li-Sn alloy for lithium batteries and beyond.展开更多
Tin(Sn)holds great promise as an anode material for next-generation lithium(Li)ion batteries but suffers from massive volume change and poor cycling performance.To clarify the dynamic chemical and microstructural evol...Tin(Sn)holds great promise as an anode material for next-generation lithium(Li)ion batteries but suffers from massive volume change and poor cycling performance.To clarify the dynamic chemical and microstructural evolution of Sn anode during lithiation and delithiation,synchrotron X-ray energydispersive diffraction and X-ray tomography are simultaneously employed during Li/Sn cell operation.The intermediate Li-Sn alloy phases during de/lithiation are identified,and their dynamic phase transformation is unraveled which is further correlated with the volume variation of the Sn at particle-and electrode-level.Moreover,we find that the Sn particle expansion/shrinkage induced particle displacement is anisotropic:the displacement perpendicular to the electrode surface(z-axis)is more pronounced compared to the directions(x-and y-axis)along the electrode surface.This anisotropic particle displacement leads to an anisotropic volume variation at the electrode level and eventually generates a net electrode expansion towards the separator after cycling,which could be one of the root causes of mechanical detachment and delamination of electrodes during long-term operation.The unraveled chemical evolution of Li-Sn and deep insights into the microstructural evolution of Sn anode provided here could guide future design and engineering of Sn and other alloy anodes for high energy density Li-and Na-ion batteries.展开更多
The severe lithium(Li)dendrite growth leads to poor cycling stability and serious safety hazards of Li metal batteries,which completely impedes their practical applications.Herein,a novel Li nucleation-diffusion-growt...The severe lithium(Li)dendrite growth leads to poor cycling stability and serious safety hazards of Li metal batteries,which completely impedes their practical applications.Herein,a novel Li nucleation-diffusion-growth mechanism based on Li-Sn alloy/Li_(3) N electrolyte(LS/LN)composite interface layer is proposed,which synergistically guides the horizontal deposition of Li to suppress the vertical growth of Li dendrite and side reactions with the electrolyte.The lithiophilic Li-Sn alloy captures Li ions to nucleate preferentially on the alloy sites,and simultaneously the Li_(3) N with low diffusion energy barrier and high Li-ion conductivity efficiently transports Li ions to nucleation sites during Li plating,consequently promoting the Li horizontal deposition.As a result,the LS/LN-Li symmetric cells can stably cycle 1600 h even at a high current density of 5 mA cm^(-2) and deposition capacity of 5 mA h cm^(-2).The LiFePO_(4)|LS/LN-Li cells with a high loading of 8.2 mg cm^(-2) present a high capacity retention of 93.4%after 1000 cycles,much higher than that using bare Li(64.8%).Furthermore,the LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)|LS/LN-Li cells present more excellent cycling stability than the cells using bare Li.The Li nucleation-diffusion-growth mechanism opens a promising route to solve the challenge of the vertical growth of Li dendrite and achieve highly stable Li metal batteries.展开更多
Electrochemical behavior of Mg, Li and Sn on tungsten electrodes in LiC1-KC1-MgCI2- SnC12 melts at 873 K was investigated. Cyclic voltammograms （CVs） showed that the underpotential deposition （UPD） of magnesium on...Electrochemical behavior of Mg, Li and Sn on tungsten electrodes in LiC1-KC1-MgCI2- SnC12 melts at 873 K was investigated. Cyclic voltammograms （CVs） showed that the underpotential deposition （UPD） of magnesium on pre-deposited tin leads to the formation of a Mg-Sn alloy, and the succeeding underpotential deposition of lithium on pre-deposited Mg-Sn alloy leads to the formation of a Mg-Li-Sn alloy. Chronopo- tentiometric measurements indicated that the codepositon of Mg, Li and Sn occurs at current densities more negative than -1.16 A.cm-~. X-ray diffraction （XRD） in- dicated that Mg2Sn phase is formed via galvanostatic electrolysis. The element Mg distributes homogeneously and Sn locates mainly on the grain boundaries in the Mg- Li-Sn alloy.展开更多
The effects of Sn content on microstructure and tensile properties of as-cast and as-extruded Mg-8Li-3Al-(1,2,3)Sn(wt.%)alloys were investigated by X-ray diffractometry(XRD),optical microscopy(OM),scanning electron mi...The effects of Sn content on microstructure and tensile properties of as-cast and as-extruded Mg-8Li-3Al-(1,2,3)Sn(wt.%)alloys were investigated by X-ray diffractometry(XRD),optical microscopy(OM),scanning electron microscopy(SEM)and tensile test.It is found that,as-cast Mg-8Li-3Al-(1,2,3)Sn alloys consist ofα-Mg+β-Li duplex matrix,MgLiAl2 and Li2Mg Sn phases.Increasing Sn content leads to grain refinement ofα-Mg dendrites and increase in content of Li2MgSn phase.During hot extrusion,complete dynamic recrystallization(DRX)takes place inβ-Li phase while incomplete DRX takes place inα-Mg phase.As Sn content is increased,the volume fraction of DRXedα-Mg grains is increased and the average grain size of DRXedα-Mg grains is decreased.Increasing Sn content is beneficial to strength but harmful to ductility for as-cast Mg-8Li-3Al-(1,2,3)Sn alloys.Tensile properties of Mg-8Li-3Al-(1,2,3)Sn alloys are improved significantly via hot extrusion and Mg-8Li-3Al-2Sn alloy exhibits the best tensile properties.展开更多
基金supported by the Natural Sciences and Engineering Research Council of Canada(NSERC)Mitacs Accelerate,Canada Foundation for Innovation(CFI),B.C.Knowledge Development Fund(BCKDF)Fenix Advanced Materials,and the University of British Columbia(UBC).
文摘Lithium metal is one of the most promising anodes to develop high energy density and safe energy storage devices due to its highest theoretical capacity(3860 mAh·g^(−1))and lowest electrochemical potential,demonstrating great potential to fulfill unprecedented demand from electronic gadgets,electric vehicles,and grid storage.Despite these good merits,lithium metal suffers from low Coulombic efficiency and dendritic growth,leading to internal short-circuiting of the cell and raising safety concerns about employing lithium metal as an anode.Recently,lithium-tin(Li-Sn)alloys,among other lithium alloys,have emerged as a potential alternative to lithium metal to efficiently suppress the lithium dendrite formation and reduce interfacial resistance for safer and longer-lasting lithium batteries.Accordingly,this work first reviews the fundamentals of Li-Sn alloys,and critically analyzes the failure mechanisms of pristine Li-metal anode and how Li-Sn alloys could overcome those challenges.The subsequent section examines various strategies to synthesize Li-Sn bulk and protection film alloys,followed by an evaluation of symmetric cell performance.Furthermore,the comparative electrochemical performance of full cells against different cathodes and solid electrolytes provides an overview of the present research.Subsequently,advanced characterization techniques were discussed to visualize lithium dendrites directly and quantify the mechanical performance of Li-Sn alloys.Last but not the least,the state-of-the-art progress of applying M-Sn(M=Na and Mg)beyond lithium batteries was summarized.In closing,this work identifies the critical challenges and provides future perspectives on Li-Sn alloy for lithium batteries and beyond.
基金sponsored by the Helmholtz Association,the China Scholarship Council(CSC)partially funded by the German Research Foundation,DFG(Project No.MA 5039/4-1)。
文摘Tin(Sn)holds great promise as an anode material for next-generation lithium(Li)ion batteries but suffers from massive volume change and poor cycling performance.To clarify the dynamic chemical and microstructural evolution of Sn anode during lithiation and delithiation,synchrotron X-ray energydispersive diffraction and X-ray tomography are simultaneously employed during Li/Sn cell operation.The intermediate Li-Sn alloy phases during de/lithiation are identified,and their dynamic phase transformation is unraveled which is further correlated with the volume variation of the Sn at particle-and electrode-level.Moreover,we find that the Sn particle expansion/shrinkage induced particle displacement is anisotropic:the displacement perpendicular to the electrode surface(z-axis)is more pronounced compared to the directions(x-and y-axis)along the electrode surface.This anisotropic particle displacement leads to an anisotropic volume variation at the electrode level and eventually generates a net electrode expansion towards the separator after cycling,which could be one of the root causes of mechanical detachment and delamination of electrodes during long-term operation.The unraveled chemical evolution of Li-Sn and deep insights into the microstructural evolution of Sn anode provided here could guide future design and engineering of Sn and other alloy anodes for high energy density Li-and Na-ion batteries.
基金supported by the Key-Area Research and Development Program of Guangdong Province (2020B090919001)the National Natural Science Foundation of China (U2001220)+3 种基金Local Innovative Research Teams Project of Guangdong Pearl River Talents Program (2017BT01N111)Shenzhen Technical Plan Project (JCYJ20180508152210821, JCYJ20170817161221958, and JCYJ20180508152135822)the All-Solid-State Lithium Battery Electrolyte Engineering Research Center (XMHT202002030)Shenzhen Graphene Manufacturing Innovation Center (201901161513)
文摘The severe lithium(Li)dendrite growth leads to poor cycling stability and serious safety hazards of Li metal batteries,which completely impedes their practical applications.Herein,a novel Li nucleation-diffusion-growth mechanism based on Li-Sn alloy/Li_(3) N electrolyte(LS/LN)composite interface layer is proposed,which synergistically guides the horizontal deposition of Li to suppress the vertical growth of Li dendrite and side reactions with the electrolyte.The lithiophilic Li-Sn alloy captures Li ions to nucleate preferentially on the alloy sites,and simultaneously the Li_(3) N with low diffusion energy barrier and high Li-ion conductivity efficiently transports Li ions to nucleation sites during Li plating,consequently promoting the Li horizontal deposition.As a result,the LS/LN-Li symmetric cells can stably cycle 1600 h even at a high current density of 5 mA cm^(-2) and deposition capacity of 5 mA h cm^(-2).The LiFePO_(4)|LS/LN-Li cells with a high loading of 8.2 mg cm^(-2) present a high capacity retention of 93.4%after 1000 cycles,much higher than that using bare Li(64.8%).Furthermore,the LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)|LS/LN-Li cells present more excellent cycling stability than the cells using bare Li.The Li nucleation-diffusion-growth mechanism opens a promising route to solve the challenge of the vertical growth of Li dendrite and achieve highly stable Li metal batteries.
基金financially supported by National High Technical Research and Development Programme of China (Nos. 2011AA03A409 and 2009AA050702)National Basic Research Program of China (No. 2007CB200906)+1 种基金the National Natural Science Foundation of China (Nos. 21103033,21101040 and 21173060)the Fundamental Research Funds for the Central Universities
文摘Electrochemical behavior of Mg, Li and Sn on tungsten electrodes in LiC1-KC1-MgCI2- SnC12 melts at 873 K was investigated. Cyclic voltammograms （CVs） showed that the underpotential deposition （UPD） of magnesium on pre-deposited tin leads to the formation of a Mg-Sn alloy, and the succeeding underpotential deposition of lithium on pre-deposited Mg-Sn alloy leads to the formation of a Mg-Li-Sn alloy. Chronopo- tentiometric measurements indicated that the codepositon of Mg, Li and Sn occurs at current densities more negative than -1.16 A.cm-~. X-ray diffraction （XRD） in- dicated that Mg2Sn phase is formed via galvanostatic electrolysis. The element Mg distributes homogeneously and Sn locates mainly on the grain boundaries in the Mg- Li-Sn alloy.
基金Project(51601076)supported by the National Natural Science Foundation of ChinaProject(17KJA430005)supported by the Natural Science Fund for Colleges and Universities in Jiangsu Province,ChinaProject(2019M650096)supported by China Postdoctoral Science Foundation。
文摘The effects of Sn content on microstructure and tensile properties of as-cast and as-extruded Mg-8Li-3Al-(1,2,3)Sn(wt.%)alloys were investigated by X-ray diffractometry(XRD),optical microscopy(OM),scanning electron microscopy(SEM)and tensile test.It is found that,as-cast Mg-8Li-3Al-(1,2,3)Sn alloys consist ofα-Mg+β-Li duplex matrix,MgLiAl2 and Li2Mg Sn phases.Increasing Sn content leads to grain refinement ofα-Mg dendrites and increase in content of Li2MgSn phase.During hot extrusion,complete dynamic recrystallization(DRX)takes place inβ-Li phase while incomplete DRX takes place inα-Mg phase.As Sn content is increased,the volume fraction of DRXedα-Mg grains is increased and the average grain size of DRXedα-Mg grains is decreased.Increasing Sn content is beneficial to strength but harmful to ductility for as-cast Mg-8Li-3Al-(1,2,3)Sn alloys.Tensile properties of Mg-8Li-3Al-(1,2,3)Sn alloys are improved significantly via hot extrusion and Mg-8Li-3Al-2Sn alloy exhibits the best tensile properties.
