Boosting of rechargeable lithium metal batteries(LMBs) holds challenges because of lithium dendrites germination and high-reactive surface feature.Separators may experience structure-determined chemical deterioration ...Boosting of rechargeable lithium metal batteries(LMBs) holds challenges because of lithium dendrites germination and high-reactive surface feature.Separators may experience structure-determined chemical deterioration and worsen Li plating-stripping behaviors when smoothly shifting from lithium-ion batteries(LIBs) to LMBs.This study precisely regulations the crystal structure of β-polypropylene and separator porous construction to investigate the intrinsic porous structure and mechanical properties determined electrochemical performances and cycling durability of LMBs.Crystal structure characterizations,porous structure analyses,and electrochemical cycling tests uncover appropriate annealing thermal stimulation concentrates β-lamellae thickness and enhances lamellae thermal stability by rearranging molecular chain in inferior β-lamellae,maximally homogenizing biaxial tensile deformation and resultant porous constructions.These even pores with high connectivity lower ion migration barriers,alleviate heterogeneous Li^(+) flux dispersion,stabilize reversible Li plating-stripping behaviors,and hinder coursing and branching of Li dendrites,endowing steady cell cycling durability,especially at higher currents due to the highlighted uncontrollable cumulation of dead Li,which offers new insights for the current pursuit of high-power density battery and fast charging technology.The suggested separator structure-chemical nature functions in ensuring cyclic cell stability and builds reliable relationships between separator structure design and practical LMBs applications.展开更多
Development of practical lithium(Li)metal batteries(LMBs)remains challenging despite promises of Li metal anodes(LMAs),owing to Li dendrite formation and highly reactive surface nature.Polyolefin separators used in LM...Development of practical lithium(Li)metal batteries(LMBs)remains challenging despite promises of Li metal anodes(LMAs),owing to Li dendrite formation and highly reactive surface nature.Polyolefin separators used in LMBs may undergo severe mechanical and chemical deterioration when contacting with LMAs.To identify the best polyolefin separator for LMBs,this study investigated the separator-deterministic cycling stability of LMBs under practical conditions,and redefined the key influencing factors,including pore structure,mechanical stability,and chemical affinity,using 12 different commercial separators,including polyethylene(PE),polypropylene(PP),and coated separators.At extreme compression triggered by LMA swelling,isotropic stress release by balancing the machine direction and transverse direction tensile strengths was found to be crucial for mitigating cell short-circuiting.Instead of PP separators,a PE separator that possesses a high elastic modulus and a highly connected pore structure can uniformly regulate LMA swelling.The ceramic coating reinforced short-circuiting resistance,while the cycling efficiency degraded rapidly owing to the detrimental interactions between ceramics and LMAs.This study identified the design principle of separators for practical LMBs with respect to mechanical stability and chemical affinity toward LMAs by elucidating the impacts of separator modification on the cycling performance.展开更多
Internal short circuits because of deformation or melting down of separators have been recognized as a root cause for many thermal runaway(TR)events of high-energy-density(HED)lithium-ion batteries(LIBs).Ceramic coati...Internal short circuits because of deformation or melting down of separators have been recognized as a root cause for many thermal runaway(TR)events of high-energy-density(HED)lithium-ion batteries(LIBs).Ceramic coating of the polyolefin separators is a promising strategy but generally hinders ionic conduction.In this study,we demonstrate that co-coating the separators with boehmite ceramics and Li_(1.5)Al_(0.5)Ti_(1.5)(PO_(4))_(3)(LATP)solid-state electrolytes could markedly improve the safety of LIBs while mitigating detrimental effects on electrochemical performance.We assembled HED(~350 Wh/kg)lithium-ion pouch cells with nickel-rich Li(Ni_(0.9)Co_(x)Mn_(0.1-x))O_(2) cathodes,silicon-based/graphite blended anodes,and co-coated separators of varying thicknesses.It is found that LATP reacts with the organic liquid electrolytes and lithium to generate a robust solid-electrolyte-interface-filled LATP layer during the formation,which can prevent the thermal deformation of separators.During the thermal abusive tests,the battery's TR failure thresholds raised from 146.2 to 162.0℃.Correspondingly,the direct failure cause of the cell TR hurdled the separator malfunction to the thermochemical reactions of the nickel-rich cathodes.Additionally,pouch cells exhibited impressive electrochemical performance,maintaining a capacity retention of 87.99%after 500 cycles at 1C.展开更多
基金the Natural Science Foundation of Shandong Province (ZR2022QB050)the Liaocheng University Doctoral Initial Fund (318052137) for Financial Support。
文摘Boosting of rechargeable lithium metal batteries(LMBs) holds challenges because of lithium dendrites germination and high-reactive surface feature.Separators may experience structure-determined chemical deterioration and worsen Li plating-stripping behaviors when smoothly shifting from lithium-ion batteries(LIBs) to LMBs.This study precisely regulations the crystal structure of β-polypropylene and separator porous construction to investigate the intrinsic porous structure and mechanical properties determined electrochemical performances and cycling durability of LMBs.Crystal structure characterizations,porous structure analyses,and electrochemical cycling tests uncover appropriate annealing thermal stimulation concentrates β-lamellae thickness and enhances lamellae thermal stability by rearranging molecular chain in inferior β-lamellae,maximally homogenizing biaxial tensile deformation and resultant porous constructions.These even pores with high connectivity lower ion migration barriers,alleviate heterogeneous Li^(+) flux dispersion,stabilize reversible Li plating-stripping behaviors,and hinder coursing and branching of Li dendrites,endowing steady cell cycling durability,especially at higher currents due to the highlighted uncontrollable cumulation of dead Li,which offers new insights for the current pursuit of high-power density battery and fast charging technology.The suggested separator structure-chemical nature functions in ensuring cyclic cell stability and builds reliable relationships between separator structure design and practical LMBs applications.
基金supported by the National Research Foundation of Korea(NRF),Government of Korea(MSIT)(2020R1A4A4079810 and 2020R1C1C1009159).
文摘Development of practical lithium(Li)metal batteries(LMBs)remains challenging despite promises of Li metal anodes(LMAs),owing to Li dendrite formation and highly reactive surface nature.Polyolefin separators used in LMBs may undergo severe mechanical and chemical deterioration when contacting with LMAs.To identify the best polyolefin separator for LMBs,this study investigated the separator-deterministic cycling stability of LMBs under practical conditions,and redefined the key influencing factors,including pore structure,mechanical stability,and chemical affinity,using 12 different commercial separators,including polyethylene(PE),polypropylene(PP),and coated separators.At extreme compression triggered by LMA swelling,isotropic stress release by balancing the machine direction and transverse direction tensile strengths was found to be crucial for mitigating cell short-circuiting.Instead of PP separators,a PE separator that possesses a high elastic modulus and a highly connected pore structure can uniformly regulate LMA swelling.The ceramic coating reinforced short-circuiting resistance,while the cycling efficiency degraded rapidly owing to the detrimental interactions between ceramics and LMAs.This study identified the design principle of separators for practical LMBs with respect to mechanical stability and chemical affinity toward LMAs by elucidating the impacts of separator modification on the cycling performance.
基金supported by the National Natural Science Foundation of China(No.U21A2080)National Key Research and Development Program of China(No.2022YFE0202400)+3 种基金Beijing Natural Science Foundation(No.JQ22028)Jilin Province Science and Technology Major Project(No.20210301021GX)Youth Talent Support Program(No.SQ2022QB02427)Youth Foundation of China GRINM Group Corporation Limited(No.2023HX012).
文摘Internal short circuits because of deformation or melting down of separators have been recognized as a root cause for many thermal runaway(TR)events of high-energy-density(HED)lithium-ion batteries(LIBs).Ceramic coating of the polyolefin separators is a promising strategy but generally hinders ionic conduction.In this study,we demonstrate that co-coating the separators with boehmite ceramics and Li_(1.5)Al_(0.5)Ti_(1.5)(PO_(4))_(3)(LATP)solid-state electrolytes could markedly improve the safety of LIBs while mitigating detrimental effects on electrochemical performance.We assembled HED(~350 Wh/kg)lithium-ion pouch cells with nickel-rich Li(Ni_(0.9)Co_(x)Mn_(0.1-x))O_(2) cathodes,silicon-based/graphite blended anodes,and co-coated separators of varying thicknesses.It is found that LATP reacts with the organic liquid electrolytes and lithium to generate a robust solid-electrolyte-interface-filled LATP layer during the formation,which can prevent the thermal deformation of separators.During the thermal abusive tests,the battery's TR failure thresholds raised from 146.2 to 162.0℃.Correspondingly,the direct failure cause of the cell TR hurdled the separator malfunction to the thermochemical reactions of the nickel-rich cathodes.Additionally,pouch cells exhibited impressive electrochemical performance,maintaining a capacity retention of 87.99%after 500 cycles at 1C.
