The high degree of crystallinity of discharging in termediates of Li-S batteries(Li_(2)S_(2)/Li_(2)S)causes a severe capacity attenuation at low temperatures.Herein,a sulfur-rich polymer is fabricated,which enables al...The high degree of crystallinity of discharging in termediates of Li-S batteries(Li_(2)S_(2)/Li_(2)S)causes a severe capacity attenuation at low temperatures.Herein,a sulfur-rich polymer is fabricated,which enables all the discharging in termediates to exist in an amorphous state without long-range order,promoti ng the substantial conversion of discharging intermediates and enhancing Li-S batteries'performance at low temperatures greatly.This cathode material exhibits excellent performance both at room and low temperatures.Even under an extremely low temperature(-40℃),the discharge capacity can remain 67% of that at room temperature.Besides,in-situ UV/Vis spectroscopy and density functional theory calculations reveal that this organosulfur cathode undergoes a new mechanism during discharge.Li_(2)S_(6) and Li_(2)S_(3) are the primary discharging intermediates that are quite different from conventional Li-S batteries.These results provide a new directi on for a broader range of applications of Li-S batteries.展开更多
Using a functionally selective solid electrolyte interphase(SEI)as an anodic protection layer can effectively avoid the subsequent settlement of uneven lithium electrodeposits for lithium sulfur(Li-S)batteries.To addr...Using a functionally selective solid electrolyte interphase(SEI)as an anodic protection layer can effectively avoid the subsequent settlement of uneven lithium electrodeposits for lithium sulfur(Li-S)batteries.To address the issues of single functional,mechanical crushing and peeling of the conventional rigid LiF SEI,a unique functional-selected rigid-flexible-coupled LiF-intercalated-graphene(LiF-GN)SEI as anodic protection is constructed,which is verified by in-operando X-ray photoelectron spectroscopy(XPS)spectra.Owing to the synergistic effect of the LiF and graphene layer,this intercalated functionalselected SEI architecture exhibits a dramatic elastic modulus(rigid-flexible coupling with a shallow Young’s modulus(~430 MPa)and a tremendous Young’s modulus of~20 GPa),high mechanical strength,and can be repulsive to polysulfides,accompanied unprecedented trafficability of Li ions.Consequently,the forceful exclusion of polysulfides from the LiF-GN SEI,as confirmed by means of in-situ UV/vis analysis,Li2 S nucleation tests,and visual permeation experiments,is of profound significance for the effective protection of Li anodes and enables Li-S batteries to achieve remarkable electrochemical performance(ultralow capacity decay rate of 0.022%during 300 cycles at 1 C and high discharge capacity of 1092 mAh/g at 0.5 C).展开更多
基金support from the National Natural Science Foundations of China (grants 52071226 and 51872193)the Natural Science Foundations of Jiangsu Province (BE2020003-3 and BK20201171)the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD).
文摘The high degree of crystallinity of discharging in termediates of Li-S batteries(Li_(2)S_(2)/Li_(2)S)causes a severe capacity attenuation at low temperatures.Herein,a sulfur-rich polymer is fabricated,which enables all the discharging in termediates to exist in an amorphous state without long-range order,promoti ng the substantial conversion of discharging intermediates and enhancing Li-S batteries'performance at low temperatures greatly.This cathode material exhibits excellent performance both at room and low temperatures.Even under an extremely low temperature(-40℃),the discharge capacity can remain 67% of that at room temperature.Besides,in-situ UV/Vis spectroscopy and density functional theory calculations reveal that this organosulfur cathode undergoes a new mechanism during discharge.Li_(2)S_(6) and Li_(2)S_(3) are the primary discharging intermediates that are quite different from conventional Li-S batteries.These results provide a new directi on for a broader range of applications of Li-S batteries.
基金the support from the National Natural Science Foundation of China(Nos.51872193,21703149,and 51622208)the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘Using a functionally selective solid electrolyte interphase(SEI)as an anodic protection layer can effectively avoid the subsequent settlement of uneven lithium electrodeposits for lithium sulfur(Li-S)batteries.To address the issues of single functional,mechanical crushing and peeling of the conventional rigid LiF SEI,a unique functional-selected rigid-flexible-coupled LiF-intercalated-graphene(LiF-GN)SEI as anodic protection is constructed,which is verified by in-operando X-ray photoelectron spectroscopy(XPS)spectra.Owing to the synergistic effect of the LiF and graphene layer,this intercalated functionalselected SEI architecture exhibits a dramatic elastic modulus(rigid-flexible coupling with a shallow Young’s modulus(~430 MPa)and a tremendous Young’s modulus of~20 GPa),high mechanical strength,and can be repulsive to polysulfides,accompanied unprecedented trafficability of Li ions.Consequently,the forceful exclusion of polysulfides from the LiF-GN SEI,as confirmed by means of in-situ UV/vis analysis,Li2 S nucleation tests,and visual permeation experiments,is of profound significance for the effective protection of Li anodes and enables Li-S batteries to achieve remarkable electrochemical performance(ultralow capacity decay rate of 0.022%during 300 cycles at 1 C and high discharge capacity of 1092 mAh/g at 0.5 C).
