In this paper we have systematically studied V-L equilibrium in ternary aqueous solutions containingvolatile electrolytes by introducing a ternary interaction term into Edwards generalized molecular thermody-namic mod...In this paper we have systematically studied V-L equilibrium in ternary aqueous solutions containingvolatile electrolytes by introducing a ternary interaction term into Edwards generalized molecular thermody-namic model and optimizing several adjustable parameters.The program PARA9 with flexible functions ofdoing a series of calculations has been developed and carried out on a TQ-16 computer.It can be usedeither for directly calculating the V-L equilibrium or for optimizing the adjustable parameters.For the sys-toms（NH3-CO3-H2O3,NH3-H2S-H2O and NH3-SO2-H2O）satisfactory results have been obtained withrelative mean deviation of 5-10%.Besides,several sets of adjustable parameters and valuable information ofactivity coefficients,equilibrium concentrations of ions and molecules in solutions are obtained.展开更多
Weakly solvating electrolyte(WSE)demonstrates superior compatibility with lithium(Li)metal batteries(LMBs).However,its application in fast-charging high-voltage LMBs is challenging.Here,we propose a diluent modified W...Weakly solvating electrolyte(WSE)demonstrates superior compatibility with lithium(Li)metal batteries(LMBs).However,its application in fast-charging high-voltage LMBs is challenging.Here,we propose a diluent modified WSE for fast-charging high-voltage LMBs,which is formed by adding diluent of 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether(TTE)into the tetrahydropyran(THP)based WSE.A relatively loose solvation structure is formed due to the formation of weak hydrogen bond between TTE and THP,which accelerates the de-solvation kinetics of Li~+.Besides,more anions are involved in solvation structure in the presence of TTE,yielding inorganic-rich interphases with improved stability.Li(30μm)||Li Ni_(0.5)Co_(0.2)Mn_(0.3)O_(2)(4.1 mAh/cm^(2))batteries with the TTE modified WSE retain over 64%capacity retention after 175 cycles under high rate of 3 C and high-voltage of 4.5 V,much better than that with pure THP based WSE.This work points out that the combination of diluent with weakly solvating solvent is a promising approach to develop high performance electrolytes for fast-charging high-voltage LMBs.展开更多
Development of advanced high-voltage electrolytes is key to achieving high-energy-density lithium metal batteries(LMBs).Weakly solvating electrolytes(WSE)can produce unique anion-driven interphasial chemistry via alte...Development of advanced high-voltage electrolytes is key to achieving high-energy-density lithium metal batteries(LMBs).Weakly solvating electrolytes(WSE)can produce unique anion-driven interphasial chemistry via altering the solvating power of the solvent,but it is difficult to dissolve the majority of Li salts and fail to cycle at a cut-off voltage above 4.5 V.Herein,we present a new-type WSE that is regulated by the anion rather than the solvent,and the first realize stable cycling of dimethoxyethane(DME)at 4.6 V without the use of the“solvent-in-salt”strategy.The relationships between the degree of dissociation of salts,the solvation structure of electrolytes,and the electrochemical performance of LMBs were systematically investigated.We found that LiBF_(4),which has the lowest degree of dissociation,can construct an anion-rich inner solvation shell,resulting in anion-derived anode/cathode interphases.Thanks to such unusual solvation structure and interphasial chemistry,the Li-LiCoO_(2)full cell with LiBF_(4)-based WSE could deliver excellent rate performance(115 mAh g^(-1)at 10 C)and outstanding cycling stability even under practical conditions,including high loading(10.7 mg cm^(-2)),thin Li(50μm),and limited electrolyte(1.2μL mg^(-1)).展开更多
Lithium(Li)batteries are major players in the power source market of electric vehicles and portable electronic devices.Electrolytes are critical to determining the performance of Li batteries.Conventional electrolytes...Lithium(Li)batteries are major players in the power source market of electric vehicles and portable electronic devices.Electrolytes are critical to determining the performance of Li batteries.Conventional electrolytes fall behind the ever-growing demands for fast-charging,wide-temperature operation,and safety properties of Li batteries.Despite the great success of(localized)high-concentration electrolytes,they still suffer from disadvantages,such as low ionic conductivity and high cost.Weakly solvating electrolytes(WSEs),also known as low-solvating electrolytes,offer another solution to these challenges,and they have attracted intensive research interests in recent years.This contribution reviews the working mechanisms,design principles,and recent advances in the development of WSEs.A summary and perspective regarding future research directions in this field is also provided.The insights will benefit academic and industrial communities in the design of safe and high-performance next-generation Li batteries.展开更多
Ether electrolytes for potassium-ion batteries exhibit a broader electrochemical window and greater applicability,yet most of them are high-concentration electrolytes with elevated cost.In this study,we propose the us...Ether electrolytes for potassium-ion batteries exhibit a broader electrochemical window and greater applicability,yet most of them are high-concentration electrolytes with elevated cost.In this study,we propose the use of a weakly solvating cyclic ether electrolyte with tetrahydropyran(THP)as the solvent.This approach induces the formation of a thin and dense inorganic-rich solid electrolyte interphase(SEI)film,which is accompanied by a decrease in the activation energy of electrode interfacial reactions due to the weak ligand binding of THP with K^(+).Density functional theory(DFT)simulations also corroborate the hypothesis that K^(+)has a lower binding energy with THP.During potassium storage process,the phenomenon of solvent co-intercalation of graphite does not occur,which greatly reduces the destruction of the graphite structure and enables a superior electrochemical performance and enhanced cycling stability at a lower concentration(2 M).At a current density of 0.2 C(55.8 mA·g^(-1)),the battery can be stably cycled for 800 cycles(approximately 8 months)with a specific capacity of 171.8 mAh·g^(-1).This study provides a new ether-based electrolyte for potassium ion batteries and effectively reduces the electrolyte cost,which is expected to inspire further development of energy storage batteries.展开更多
The solid-state polymer electrolyte fabricated by ring-opening polymerization(ROP)of cyclic ether has been known as an efficient means to increase high-voltage stability despite the challenges of uncontrolled degrees ...The solid-state polymer electrolyte fabricated by ring-opening polymerization(ROP)of cyclic ether has been known as an efficient means to increase high-voltage stability despite the challenges of uncontrolled degrees of polymerization and low ionic conductivity.Here,through unveiling the ROP mechanism of a conventional cyclic ether(1,3-dioxolane),we found that through molecular engineering of the methoxyl(–OCH_(3))on the skeleton of the ring,the ROP is not thermodynamically favorable due to its dispersed electron density.Simultaneously,the electron-withdrawing characteristics of–OCH_(3) increase the high-voltage stability,enabling compatibility with the high-voltage cathode without the need for polymerization.Moreover,using lithium bis(fluorosulfonyl)imide(LiFSI)as a single salt,the merits of weak solvation capability promote the formation of inorganic rich solid electrolyte interphase and provide the coulombic efficiency of 99.36%for lithium striping/plating.The lithium metal batteries using a LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2) cathode and thin lithium(50μm)can maintain ultralong cycling performance up to 1180 cycles(80%capacity retention)or calendar life over 6500 h(more than nine months).Our work deepens the fundamental understanding of how ROP regulates electrochemical reactions and affords an effective approach to designing cyclic ether electrolytes for energy-dense battery systems.展开更多
文摘In this paper we have systematically studied V-L equilibrium in ternary aqueous solutions containingvolatile electrolytes by introducing a ternary interaction term into Edwards generalized molecular thermody-namic model and optimizing several adjustable parameters.The program PARA9 with flexible functions ofdoing a series of calculations has been developed and carried out on a TQ-16 computer.It can be usedeither for directly calculating the V-L equilibrium or for optimizing the adjustable parameters.For the sys-toms（NH3-CO3-H2O3,NH3-H2S-H2O and NH3-SO2-H2O）satisfactory results have been obtained withrelative mean deviation of 5-10%.Besides,several sets of adjustable parameters and valuable information ofactivity coefficients,equilibrium concentrations of ions and molecules in solutions are obtained.
基金supported by Hengyang City,Hunan Province Science and Technology Innovation Project(No.202250045319)the National Natural Science Foundation of China(Nos.11375084,21808125)the Scientific Research Planning Project of Jilin Provincial Education Department(No.JJKH20241249KJ)。
文摘Weakly solvating electrolyte(WSE)demonstrates superior compatibility with lithium(Li)metal batteries(LMBs).However,its application in fast-charging high-voltage LMBs is challenging.Here,we propose a diluent modified WSE for fast-charging high-voltage LMBs,which is formed by adding diluent of 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether(TTE)into the tetrahydropyran(THP)based WSE.A relatively loose solvation structure is formed due to the formation of weak hydrogen bond between TTE and THP,which accelerates the de-solvation kinetics of Li~+.Besides,more anions are involved in solvation structure in the presence of TTE,yielding inorganic-rich interphases with improved stability.Li(30μm)||Li Ni_(0.5)Co_(0.2)Mn_(0.3)O_(2)(4.1 mAh/cm^(2))batteries with the TTE modified WSE retain over 64%capacity retention after 175 cycles under high rate of 3 C and high-voltage of 4.5 V,much better than that with pure THP based WSE.This work points out that the combination of diluent with weakly solvating solvent is a promising approach to develop high performance electrolytes for fast-charging high-voltage LMBs.
基金supported by the Key Program for International S&T Cooperation Projects of China(No.2017YFE0124300)National Natural Science Foundation of China(Nos.51971002,52171205 and 52171197)+1 种基金Natural Science Foundation of Anhui Provincial Education Department(KJ2021A0393)Anhui Provincial Natural Science Foundation for Excellent Youth Scholars(No.2108085Y16).
文摘Development of advanced high-voltage electrolytes is key to achieving high-energy-density lithium metal batteries(LMBs).Weakly solvating electrolytes(WSE)can produce unique anion-driven interphasial chemistry via altering the solvating power of the solvent,but it is difficult to dissolve the majority of Li salts and fail to cycle at a cut-off voltage above 4.5 V.Herein,we present a new-type WSE that is regulated by the anion rather than the solvent,and the first realize stable cycling of dimethoxyethane(DME)at 4.6 V without the use of the“solvent-in-salt”strategy.The relationships between the degree of dissociation of salts,the solvation structure of electrolytes,and the electrochemical performance of LMBs were systematically investigated.We found that LiBF_(4),which has the lowest degree of dissociation,can construct an anion-rich inner solvation shell,resulting in anion-derived anode/cathode interphases.Thanks to such unusual solvation structure and interphasial chemistry,the Li-LiCoO_(2)full cell with LiBF_(4)-based WSE could deliver excellent rate performance(115 mAh g^(-1)at 10 C)and outstanding cycling stability even under practical conditions,including high loading(10.7 mg cm^(-2)),thin Li(50μm),and limited electrolyte(1.2μL mg^(-1)).
基金supported by the Hong Kong Polytechnic University(No.CDBJ)Z.Wang thanks the funding support from the Centrally Funded Postdoctoral Fellowship Scheme of the Hong Kong Polytechnic University(No.1-YXAU).
文摘Lithium(Li)batteries are major players in the power source market of electric vehicles and portable electronic devices.Electrolytes are critical to determining the performance of Li batteries.Conventional electrolytes fall behind the ever-growing demands for fast-charging,wide-temperature operation,and safety properties of Li batteries.Despite the great success of(localized)high-concentration electrolytes,they still suffer from disadvantages,such as low ionic conductivity and high cost.Weakly solvating electrolytes(WSEs),also known as low-solvating electrolytes,offer another solution to these challenges,and they have attracted intensive research interests in recent years.This contribution reviews the working mechanisms,design principles,and recent advances in the development of WSEs.A summary and perspective regarding future research directions in this field is also provided.The insights will benefit academic and industrial communities in the design of safe and high-performance next-generation Li batteries.
基金financial support from the National Key Research and Development Program of China(No.2022YFB2404300)the National Natural Science Foundation of China(Nos.22409153 and 52101269).
文摘Ether electrolytes for potassium-ion batteries exhibit a broader electrochemical window and greater applicability,yet most of them are high-concentration electrolytes with elevated cost.In this study,we propose the use of a weakly solvating cyclic ether electrolyte with tetrahydropyran(THP)as the solvent.This approach induces the formation of a thin and dense inorganic-rich solid electrolyte interphase(SEI)film,which is accompanied by a decrease in the activation energy of electrode interfacial reactions due to the weak ligand binding of THP with K^(+).Density functional theory(DFT)simulations also corroborate the hypothesis that K^(+)has a lower binding energy with THP.During potassium storage process,the phenomenon of solvent co-intercalation of graphite does not occur,which greatly reduces the destruction of the graphite structure and enables a superior electrochemical performance and enhanced cycling stability at a lower concentration(2 M).At a current density of 0.2 C(55.8 mA·g^(-1)),the battery can be stably cycled for 800 cycles(approximately 8 months)with a specific capacity of 171.8 mAh·g^(-1).This study provides a new ether-based electrolyte for potassium ion batteries and effectively reduces the electrolyte cost,which is expected to inspire further development of energy storage batteries.
基金supported by the National Natural Science Foundation of China(grant nos.22372083,52201259,and 22393900)the Young Elite Scientist Sponsorship Program by China Association for Science and Technology,the National Key R&D Program of China(grant no.2021YFB2500300)the Natural Science Foundation of Tianjin(grant no.22JCZDJC00380).
文摘The solid-state polymer electrolyte fabricated by ring-opening polymerization(ROP)of cyclic ether has been known as an efficient means to increase high-voltage stability despite the challenges of uncontrolled degrees of polymerization and low ionic conductivity.Here,through unveiling the ROP mechanism of a conventional cyclic ether(1,3-dioxolane),we found that through molecular engineering of the methoxyl(–OCH_(3))on the skeleton of the ring,the ROP is not thermodynamically favorable due to its dispersed electron density.Simultaneously,the electron-withdrawing characteristics of–OCH_(3) increase the high-voltage stability,enabling compatibility with the high-voltage cathode without the need for polymerization.Moreover,using lithium bis(fluorosulfonyl)imide(LiFSI)as a single salt,the merits of weak solvation capability promote the formation of inorganic rich solid electrolyte interphase and provide the coulombic efficiency of 99.36%for lithium striping/plating.The lithium metal batteries using a LiNi_(0.6)Co_(0.2)Mn_(0.2)O_(2) cathode and thin lithium(50μm)can maintain ultralong cycling performance up to 1180 cycles(80%capacity retention)or calendar life over 6500 h(more than nine months).Our work deepens the fundamental understanding of how ROP regulates electrochemical reactions and affords an effective approach to designing cyclic ether electrolytes for energy-dense battery systems.
