Developing nonflammable electrolyte with a wide electrochemical window has become an urgent demand for high-energy-density and high-safe lithium-ion batteries(LIBs).Herein,a fluorinated nonflammable phosphate electrol...Developing nonflammable electrolyte with a wide electrochemical window has become an urgent demand for high-energy-density and high-safe lithium-ion batteries(LIBs).Herein,a fluorinated nonflammable phosphate electrolyte is developed to construct a safe 4.5 V-class LIB(Si-SiC-C/0.35Li2MnO3-0.65LiNi0.5Mn0.5O2).The proposed fluorinated phosphate electrolyte,0.8 M LiPF6/tris(2,2,2-trifluoroethyl)phosphate(TFEP)+5 vol%fluoroethylene carbonate(FEC)+5 vol%vinylene carbonate(VC),is not only completely nonflammable but also exhibits excellent oxidative/reductive stability on 0.35Li2MnO30.65LiNi0.5Mn0.5O2 cathode and Si-SiC-C anode.The in situ differential electrochemical mass spectrometry and X-ray photoelectron spectroscopy proved that TFEP-based electrolyte does not decompose into gases but forms a high-quality electrode-electrolyte interface on cathode surface at high working potential.The 4.5 V-class LIBs using 0.8 M LiPF6 TFEP-based nonflammable electrolyte shed some light on potential application for high-safe and low-cost larger-scale energy storage.展开更多
Lithium-based batteries have had a profound impact on modern society through their extensive use in portable electronic devices,electric vehicles,and energy storage systems.However,battery safety issues such as therma...Lithium-based batteries have had a profound impact on modern society through their extensive use in portable electronic devices,electric vehicles,and energy storage systems.However,battery safety issues such as thermal runaway,fire,and explosion hinder their practical application,especially for using metal anode.These problems are closely related to the high flammability of conventional electrolytes and have prompted the study of flameretardant and nonflammable electrolytes.Here,we review the recent research on nonflammable electrolytes used in lithium-based batteries,including phosphates,fluorides,fluorinated phosphazenes,ionic liquids,deep eutectic solvents,aqueous electrolytes,and solid-state electrolytes.Their flame-retardant mechanisms and efficiency are discussed,as well as their influence on cell electrochemical performance.We conclude with a summary of future prospects for the design of nonflammable electrolytes and the construction of safer lithium-based batteries.展开更多
Lithium metal batteries(LMBs)show great promise for achieving energy densities over 400 Wh·kg^(-1).However,highly flammable organic electrolytes are a long-lasting problem that triggers safety hazards and hinders...Lithium metal batteries(LMBs)show great promise for achieving energy densities over 400 Wh·kg^(-1).However,highly flammable organic electrolytes are a long-lasting problem that triggers safety hazards and hinders the commercial application of LMBs.Here,a nonflammable diluted highly concentrated electrolyte(DHCE)with ethoxy(pentafluoro)cyclotriphosphazene(PFPN)as a diluent is developed to simultaneously achieve high safety and cycling stability of high-voltage LMBs.The optimal DHCE not only ensures reversible Li deposition/dissolution behavior with a superior average Coulombic efficiency(CE)over 99.1%on lithium metal anode(LMA),but also suppresses side reactions and stress crack on the LiCoO_(2)(LCO)under high cut-off voltage.The newly developed DHCE exhibits high thermal stability,showing complete nonflammability and reduced heat generation between the electrolyte and delithiated LCO/cycled LMA.This work offers an opportunity for rational designing nonflammable electrolytes toward high-voltage and safe LMBs.展开更多
The formation of lithium dendrites and the safety hazards arising from flammable liquid electrolytes have seriously hindered the development of high-energy-density lithium metal batteries.Herein,an emerging amide-base...The formation of lithium dendrites and the safety hazards arising from flammable liquid electrolytes have seriously hindered the development of high-energy-density lithium metal batteries.Herein,an emerging amide-based electrolyte is proposed,containing LiTFSI and butyrolactam in different molar ratios.1,1,2,2-Tetrafluoroethyl-2,2,3,3-tetrafluoropropylether and fluoroethylene carbonate are introduced into the amide-based electrolyte as counter solvent and additives.The well-designed amide-based electrolyte possesses nonflammability,high ionic conductivity,high thermal stability and electrochemical stability(>4.7 V).Besides,an inorganic/organic-rich solid electrolyte interphase with an abundance of LiF,Li3N and Li-N-C is in situ formed,leading to spherical lithium deposition.The formation mechanism and solvation chemistry of amide-based electrolyte are further inves-tigated by molecular dynamics simulations and density functional theory.When applied in Li metal batteries with LiFePO4 and LiMn2O4 cathode,the amide-based electrolyte can enable stable cycling performance at room temperature and 60℃.This study provides a new insight into the development of amide-based electrolytes for lithium metal batteries.展开更多
Rechargeable lithium-based battery is hailed as next-generation high-energy-density battery systems.However, growth of lithium dendrites, shuttle effect of lithium polysulfides intermediates and unstable interphase of...Rechargeable lithium-based battery is hailed as next-generation high-energy-density battery systems.However, growth of lithium dendrites, shuttle effect of lithium polysulfides intermediates and unstable interphase of high-voltage intercalation-type cathodes largely prevent their practical deployment.Herein, to fully conquer the three challenges via one strategy, a novel electrolyte with highlycoordinated solvation structure-in-nonsolvent is designed. On account of the particular electrolyte structure, the shuttle effect is completely suppressed by quasi-solid conversion of S species in Li-S batteries,with a stable cycle performance even at lean electrolyte(5μL mg^(-1)). Simultaneously, in-situ-formed highly-fluorinated interphases can not only lower Li+diffusion barrier to ensure uniform nucleation of Li but also improve stability of NCM cathodes, which enable excellent capacity retention of Lik LiNi(0.5)Co(0.2)Mn(0.3)O2 batteries under conditions toward practical applications(high loading of 2.7 m Ah cm^(-2) and lean electrolyte of 5 m L Ah^(-1)). Besides, the electrolyte is also nonflammable. This electrolyte structure offers useful guidelines for the design of novel organic electrolytes for practical lithium-based batteries.展开更多
The properties of trimethyl phosphate（TMP）-based nonflammable electrolytes with LiPF6 as solute were investigated using graphite anode and LiCoO2 cathode. The effect of TMP on non-flammability of electrolytes was al...The properties of trimethyl phosphate（TMP）-based nonflammable electrolytes with LiPF6 as solute were investigated using graphite anode and LiCoO2 cathode. The effect of TMP on non-flammability of electrolytes was also evaluated. It is found that the TMP reduction decomposition on graphite electrode at the potential of 1.3V （vs Li/Li+） is suppressed with ethylene carbonate（EC）, dimethyl carbonate（DMC） and ethylmethyl carbonate（EMC） cosolvents and vinylene carbonate（VC） additives. The results show that the non-flammable electrolyte of 1mol/L LiPF6 61%（EC1.5-DMC1.0-EMC1.0）-39% TMP has good electrochemical properties. The discharge capacities of half-cells after 20 cycles are 254.8mA·h/g for Li/graphite and 144.1mA·h/g for Li/LiCoO2. The （graphite/）（LiCoO2） prismatic lithium-ion cell delivers a discharge capacity of 131mA·h/g at first cycle. With an addition of 4%VC to this non-flammable electrolyte, a discharge capacity of 134mA·h/g at first cycle and a capacity ratio of （84.3%） after 50 cycles are obtained for prismatic lithium-ion batteries. Furthermore, a nail penetration test demonstrates that the safety of prismatic lithium-ion batteries is dramatically improved by using TMP-containing （non-）（flammable） electrolytes.展开更多
基金National Key R&D Program of China,Grant/Award Number:2016YFB0100200National Nature Science Foundation of China,Grant/Award Number:21972108+2 种基金supported by the National Key R&D Program of China(No.2016YFB0100200)National Nature Science Foundation of China(Nos.21972108 and 21673165)the Supercomputing Center of Wuhan University.
文摘Developing nonflammable electrolyte with a wide electrochemical window has become an urgent demand for high-energy-density and high-safe lithium-ion batteries(LIBs).Herein,a fluorinated nonflammable phosphate electrolyte is developed to construct a safe 4.5 V-class LIB(Si-SiC-C/0.35Li2MnO3-0.65LiNi0.5Mn0.5O2).The proposed fluorinated phosphate electrolyte,0.8 M LiPF6/tris(2,2,2-trifluoroethyl)phosphate(TFEP)+5 vol%fluoroethylene carbonate(FEC)+5 vol%vinylene carbonate(VC),is not only completely nonflammable but also exhibits excellent oxidative/reductive stability on 0.35Li2MnO30.65LiNi0.5Mn0.5O2 cathode and Si-SiC-C anode.The in situ differential electrochemical mass spectrometry and X-ray photoelectron spectroscopy proved that TFEP-based electrolyte does not decompose into gases but forms a high-quality electrode-electrolyte interface on cathode surface at high working potential.The 4.5 V-class LIBs using 0.8 M LiPF6 TFEP-based nonflammable electrolyte shed some light on potential application for high-safe and low-cost larger-scale energy storage.
基金We acknowledge financial support from the National Key R&D Program of China(2018YFA0209600)the Natural Science Foundation of China(22022813,21878268)the Leading Innovative and Entrepreneur Team Introduction Program of Zhejiang(2019R01006).
文摘Lithium-based batteries have had a profound impact on modern society through their extensive use in portable electronic devices,electric vehicles,and energy storage systems.However,battery safety issues such as thermal runaway,fire,and explosion hinder their practical application,especially for using metal anode.These problems are closely related to the high flammability of conventional electrolytes and have prompted the study of flameretardant and nonflammable electrolytes.Here,we review the recent research on nonflammable electrolytes used in lithium-based batteries,including phosphates,fluorides,fluorinated phosphazenes,ionic liquids,deep eutectic solvents,aqueous electrolytes,and solid-state electrolytes.Their flame-retardant mechanisms and efficiency are discussed,as well as their influence on cell electrochemical performance.We conclude with a summary of future prospects for the design of nonflammable electrolytes and the construction of safer lithium-based batteries.
基金supported by the Science and Technology Project of State Grid Corporation of China(No.4000-202320087A-1-1-ZN).
文摘Lithium metal batteries(LMBs)show great promise for achieving energy densities over 400 Wh·kg^(-1).However,highly flammable organic electrolytes are a long-lasting problem that triggers safety hazards and hinders the commercial application of LMBs.Here,a nonflammable diluted highly concentrated electrolyte(DHCE)with ethoxy(pentafluoro)cyclotriphosphazene(PFPN)as a diluent is developed to simultaneously achieve high safety and cycling stability of high-voltage LMBs.The optimal DHCE not only ensures reversible Li deposition/dissolution behavior with a superior average Coulombic efficiency(CE)over 99.1%on lithium metal anode(LMA),but also suppresses side reactions and stress crack on the LiCoO_(2)(LCO)under high cut-off voltage.The newly developed DHCE exhibits high thermal stability,showing complete nonflammability and reduced heat generation between the electrolyte and delithiated LCO/cycled LMA.This work offers an opportunity for rational designing nonflammable electrolytes toward high-voltage and safe LMBs.
基金supported by the National Natural Science Foundation of China(21905069,52002094)the Shenzhen Science and Technology Innovation Committee(JCYJ20180507183907224,KQTD20170809110344233)+2 种基金the Economic,Trade and Information Commission of Shenzhen Municipality through the Graphene Manufacture Innovation Center(201901161514)the Guangdong Province Covid-19 Pandemic Control Research Fund(2020KZDZX1220)the School Research Startup Expenses of Harbin Institute of Technology(Shenzhen)(DD29100027).
文摘The formation of lithium dendrites and the safety hazards arising from flammable liquid electrolytes have seriously hindered the development of high-energy-density lithium metal batteries.Herein,an emerging amide-based electrolyte is proposed,containing LiTFSI and butyrolactam in different molar ratios.1,1,2,2-Tetrafluoroethyl-2,2,3,3-tetrafluoropropylether and fluoroethylene carbonate are introduced into the amide-based electrolyte as counter solvent and additives.The well-designed amide-based electrolyte possesses nonflammability,high ionic conductivity,high thermal stability and electrochemical stability(>4.7 V).Besides,an inorganic/organic-rich solid electrolyte interphase with an abundance of LiF,Li3N and Li-N-C is in situ formed,leading to spherical lithium deposition.The formation mechanism and solvation chemistry of amide-based electrolyte are further inves-tigated by molecular dynamics simulations and density functional theory.When applied in Li metal batteries with LiFePO4 and LiMn2O4 cathode,the amide-based electrolyte can enable stable cycling performance at room temperature and 60℃.This study provides a new insight into the development of amide-based electrolytes for lithium metal batteries.
基金financial support from the National Key Research and Development Program of China (2018YFB0104200)。
文摘Rechargeable lithium-based battery is hailed as next-generation high-energy-density battery systems.However, growth of lithium dendrites, shuttle effect of lithium polysulfides intermediates and unstable interphase of high-voltage intercalation-type cathodes largely prevent their practical deployment.Herein, to fully conquer the three challenges via one strategy, a novel electrolyte with highlycoordinated solvation structure-in-nonsolvent is designed. On account of the particular electrolyte structure, the shuttle effect is completely suppressed by quasi-solid conversion of S species in Li-S batteries,with a stable cycle performance even at lean electrolyte(5μL mg^(-1)). Simultaneously, in-situ-formed highly-fluorinated interphases can not only lower Li+diffusion barrier to ensure uniform nucleation of Li but also improve stability of NCM cathodes, which enable excellent capacity retention of Lik LiNi(0.5)Co(0.2)Mn(0.3)O2 batteries under conditions toward practical applications(high loading of 2.7 m Ah cm^(-2) and lean electrolyte of 5 m L Ah^(-1)). Besides, the electrolyte is also nonflammable. This electrolyte structure offers useful guidelines for the design of novel organic electrolytes for practical lithium-based batteries.
文摘The properties of trimethyl phosphate（TMP）-based nonflammable electrolytes with LiPF6 as solute were investigated using graphite anode and LiCoO2 cathode. The effect of TMP on non-flammability of electrolytes was also evaluated. It is found that the TMP reduction decomposition on graphite electrode at the potential of 1.3V （vs Li/Li+） is suppressed with ethylene carbonate（EC）, dimethyl carbonate（DMC） and ethylmethyl carbonate（EMC） cosolvents and vinylene carbonate（VC） additives. The results show that the non-flammable electrolyte of 1mol/L LiPF6 61%（EC1.5-DMC1.0-EMC1.0）-39% TMP has good electrochemical properties. The discharge capacities of half-cells after 20 cycles are 254.8mA·h/g for Li/graphite and 144.1mA·h/g for Li/LiCoO2. The （graphite/）（LiCoO2） prismatic lithium-ion cell delivers a discharge capacity of 131mA·h/g at first cycle. With an addition of 4%VC to this non-flammable electrolyte, a discharge capacity of 134mA·h/g at first cycle and a capacity ratio of （84.3%） after 50 cycles are obtained for prismatic lithium-ion batteries. Furthermore, a nail penetration test demonstrates that the safety of prismatic lithium-ion batteries is dramatically improved by using TMP-containing （non-）（flammable） electrolytes.
