Lithium(Li)metal batteries hold great promise due to their high energy density,yet severe side reactions between routine organic electrolytes and the Li metal anode hinder their practical implementation.Elucidating th...Lithium(Li)metal batteries hold great promise due to their high energy density,yet severe side reactions between routine organic electrolytes and the Li metal anode hinder their practical implementation.Elucidating the fundamental mechanisms that govern electrolyte stability on the Li metal anode is crucial to stabilizing the electrolyte-anode interface and promoting the practical applications of Li metal batteries.Herein,the regulation mechanism of the anode surface on the electrolyte stability is revealed at the atomic scale by density functional theory calculations.Indicated by the changes in the lowest unoccupied molecular orbital(LUMO)energy levels,solvents exhibit markedly lower reductive stability on Li metal surfaces compared with bulk molecules,making them more prone to parasitic reactions.Two major components in solid electrolyte interphase(SEI),i.e.,LiF and Li_(2)O,can passivate the solvent reduction through an average increase of 1.46 eV in their LUMO energy levels.The LUMO energy changes are further correlated with the Li-O distance between the solvents and SEI components,exhibiting an approximately linear relationship.This work reveals the role of the SEI in protecting Li metal anodes from electrolyte corrosion and identifies key factors regulating solvent stability,providing fundamental insights for the rational design of advanced electrolytes and robust SEI for practical Li metal batteries.展开更多
The temperature stability of supercapacitor（SC） is largely determined by the properties of the electrolyte.Hydrogel electrolytes（HGE）, due to their hydrophilic polymer skeleton, show different temperature stabilit...The temperature stability of supercapacitor（SC） is largely determined by the properties of the electrolyte.Hydrogel electrolytes（HGE）, due to their hydrophilic polymer skeleton, show different temperature stability to that of liquid aqueous electrolytes. In this study, symmetric activated carbon（AC） SCs had been assembled with in situ electrodeposited poly（vinyl alcohol） potassium borate（PVAPB） HGE. The electrochemical performance of the SCs was systematically studied at different temperatures. Results show that the conductivity of PVAPB HGE is comparable with that of liquid aqueous electrolytes at different temperatures. The operating temperature range of PVAPB HGE SCs is -5–60°C, while those of the 1 mol/L Na2SO4SCs and the 0.9 mol/L KClSCs are 20–80°C and 20–40°C, respectively. The specific capacitance of PVAPB HGE SC is higher than those of SCs using liquid aqueous electrolytes at any temperature. The excellent temperature stability of PVAPB HGE makes it possible to build stable aqueous SCs in the wider temperature range.展开更多
Solid-state electrolytes(SSEs)play a pivotal role in advancing next-generation lithium metal battery technology.However,they commonly encounter substantial interfacial resistance and poor stability when interfacing wi...Solid-state electrolytes(SSEs)play a pivotal role in advancing next-generation lithium metal battery technology.However,they commonly encounter substantial interfacial resistance and poor stability when interfacing with lithium metal,hindering practical applications.Herein,we introduce a flexible metal-organic framework(MOF:NUS-6)-incorporated polymeric layer,denoted as NP,designed to protect the sodium superionic conductor(NASICON)-type Li_(1.3)Al_(0.3)Ti_(1.7)(PO_(4))_(3)(LATP)electrolyte from Li metal anodes.The NP matrix establishes a soft interface with the LATP surface,effectively reducing voids and gaps that may arise between the LATP electrolyte and Li metal.Moreover,the MOF component in NP enhances ionic conductivity,offers abundant Li^(+)transport sites,and provides hierarchical ion channels,ensuring a homogeneous Li^(+)flow and thus effectively inhibiting Li dendrite formation.Utilizing NP,we fabricate Li symmetrical cells cycled for over 1600 h at 0.2 mA cm^(-2)and all-solid-state LiINP-LATPI LiFePO_(4)batteries,achieving a remarkable 99.3%capacity retention after 200 cycles at 0.2 C.This work outlines a general strategy for designing long-lasting and stable solid-state Li metal batteries.展开更多
A Li/KNO_(3) composite(LKNO),with KNO_(3) uniformly implanted in bulk metallic Li,is fabricated for battery anode via a facile mechanical kneading approach,which exhibits high Coulombic efficiency and prolonged cycle ...A Li/KNO_(3) composite(LKNO),with KNO_(3) uniformly implanted in bulk metallic Li,is fabricated for battery anode via a facile mechanical kneading approach,which exhibits high Coulombic efficiency and prolonged cycle life.The mechanism behind the enhanced electrochemical performance of the“salt-in-metal”composite is investigated,where KNO_(3) in metallic Li composite electrode would be sustainably released into the electrolyte.The presence of NO_(3)-stabilizes the solid electrolyte interphase by producing functional Li_(3)N,LiNxOy,and Li_(2)O species.K^(+)from KNO_(3) also helps to form an electrostatic shield after its adsorption on the electrode protrusions,which suppresses the dendritic growth of metallic Li.With the above advantages,uniform Li plating with dense and planar structure is realized for the LKNO electrode.These findings reveal a deep understanding of the effect of the“saltin-metal”anode and provide new insights into the use of nitrate additives for high-energy-density Li metal batteries.展开更多
Non-aqueous lithium-oxygen （Li-O2） batteries have been considered as the superior energy storage system due to their high-energy density, however, some challenges limit the practical application of Li- O2 batteries....Non-aqueous lithium-oxygen （Li-O2） batteries have been considered as the superior energy storage system due to their high-energy density, however, some challenges limit the practical application of Li- O2 batteries. One of them is the lack of stable electrolyte. In this communication, a novel electrolyte with ethylene sulfite （ES） used as solvent for Li-O2 batteries was reported. ES solvent showed low volatility and high electrochemical stability. Without a catalyst in the air-electrode of Li-O2 batteries, the batteries showed high specific capacity, good round-trip efficiency and cycling stability.展开更多
Electrical double-layer capacitors(EDLCs)consist of energy storage devices that present high-power and moderate energy density.The electrolyte and electrode physicochemical properties are crucial for improving their o...Electrical double-layer capacitors(EDLCs)consist of energy storage devices that present high-power and moderate energy density.The electrolyte and electrode physicochemical properties are crucial for improving their overall energy storage capabilities.Therefore,the stability of the EDLCs’materials is the primary focus of this study.Since energy storage depends on the specific capacitance,and also on the square of the maximum capacitive cell voltage(UMCV).Thus,electrodes with high specific surface area(SSA)and electrolytes with excellent electrochemical stability are commonly reported in the literature.Aqueous electrolytes are safer and green devices compared to other organic-based solutions.On the other hand,their UMCVis reduced compared to other electrolytes(e.g.,organic-based and ionic liquids).In this sense,spanning the UMCVfor aqueous-based electrolytes is a’hot topic’research.Unfortunately,the lack of protocols to establish reliable UMCVvalues has culminated in the publishing of several conflicting results.Herein,we confirm that multiwalled carbon nanotubes(MWCNTs)housed in cells degrade and produce CO_(2) under abusive polarisation conditions.It is probed by employing electrochemical techniques,in-situ FTIR and in-situ Raman spectroscopies.From these considerations,the current study uses spectro-electrochemical techniques to support the correct determination of the electrode and electrolyte stability conditions as a function of the operating electrochemical parameters.展开更多
A novel electrolyte with chloromethyl pivalate （CP） used as solvent was first reported for non-aqueous lithium-oxygen （Li-O2） batteries. Since there are no α-H atoms in the structure of CP, the CP based electroly...A novel electrolyte with chloromethyl pivalate （CP） used as solvent was first reported for non-aqueous lithium-oxygen （Li-O2） batteries. Since there are no α-H atoms in the structure of CP, the CP based electrolyte in both superoxide radical solution and real LifO2 battery environment showed good chemical stability against superoxide radicals, which was confirmed by ^1H NMR and ^13C NMR measurements. Without a catalyst in the cathode of Li-O2 batteries, the batteries showed high specific capacity and cycling stability.展开更多
The development of high-performance electrolyte-supported reversible solid oxide cells(RSOCs)is significantly hindered by the limitations of existing electrolyte materials,particularly in achieving high ionic conducti...The development of high-performance electrolyte-supported reversible solid oxide cells(RSOCs)is significantly hindered by the limitations of existing electrolyte materials,particularly in achieving high ionic conductivity and long-term stability under targeted operating conditions.While scandia stabilized zirconia(ScSZ)exhibits the highest ionic conductivity among zirconia-based electrolytes,ScSZ rapid conductivity degradation during prolonged operation remains a significant obstacle to commercialization.To address this pressing challenge,both binary and ternary co-doping were explored,incorporating Mg^(2+),In^(3+),Yb^(3+),and Sm^(3+)into the base composition of(Sc_(2)O_(3))_(0.11)(ZrO_(2))_(0.89)(11ScSZ).Among these,the optimized ternary co-doped composition,(In_(2)O_(3))_(0.0025)(Yb_(2)O_(3))_(0.0025)(Sc_(2)O_(3))_(0.11)(ZrO_(2))_(0.885)(0.25In0.25Yb11ScSZ),demonstrates significant enhancements in both ionic conductivity and stability.This ternary co-doped electrolyte exhibits superior conductivity and nearly double the stability of undoped 11ScSZ.In addition,it exhibits an enhanced flexural strength even higher than state-of-the-art electrolytes(161 MPa)and respectably wide electrolytic domain(10^(-16)-10^(-27)atm at 800℃).When implemented in 200μm-thick electrolyte-supported RSOC devices,the 0.25In0.25Yb11ScSZ electrolyte enables record-breaking performance,achieving a peak power density(PPD)of 1.02 W cm^(-2)in fuel cell(FC)mode and a current density of 1.05 A cm^(-2)at 1.3 V in electrolysis cell(EC)mode at 800℃both representing two-to three-fold improvement over state-of-the-art systems.These exceptional performance metrics,combined with excellent long-term durability,rank among the highest reported for electrolyte-supported cells,highlighting the potential of this novel ternary co-doped electrolyte for high-performance RSOC technologies capable of meeting the demanding requirements of next-generation energy systems.展开更多
Reversible solid oxide cells(SOCs)are very efficient and clean for storage and regeneration of renewable electrical energy by switching between electrolysis and fuel cell modes.One of the most critical factors governi...Reversible solid oxide cells(SOCs)are very efficient and clean for storage and regeneration of renewable electrical energy by switching between electrolysis and fuel cell modes.One of the most critical factors governing the efficiency and durability of SOCs technology is the stability of the interface between oxygen electrode and electrolyte,which is conventionally formed by sintering at a high temperature of~1000–1250℃,and which suffers from delamination problem,particularly for reversibly operated SOCs.On the other hand,our recent studies have shown that the electrode/electrolyte interface can be in situ formed by a direct assembly approach under the electrochemical polarization conditions at 800℃and lower.The direct assembly approach provides opportunities for significantly simplifying the cell fabrication procedures without the doped ceria barrier layer,enabling the utilization of a variety of high-performance oxygen electrode materials on barrier layer–free yttria-stabilized zirconia(YSZ)electrolyte.Most importantly,the in situ polarization induced interface shows a promising potential as highly active and durable interface for reversible SOCs.The objective of this progress report is to take an overview of the origin and research progress of in situ fabrication of oxygen electrodes based on the direct assembly approach.The prospect of direct assembly approach in the development of effective SOCs and in the fundamental studies of electrode/electrolyte interface reactions is discussed.展开更多
The building of safe and high energy-density lithium batteries is strongly dependent on the electrochemical performance of working electrolytes, in which ion–solvent interactions play a vital role. Herein, the ion–s...The building of safe and high energy-density lithium batteries is strongly dependent on the electrochemical performance of working electrolytes, in which ion–solvent interactions play a vital role. Herein, the ion–solvent chemistry is developed from mono-solvent to multi-solvent complexes to probe the solvation structure and the redox stability of practical electrolytes. The decrease in energies of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) of solvents in lithium-ion solvation shells becomes less significant as the number of coordinated solvents increases, but both the HOMO and LUMO energies of the coordinated solvents remain lower than those of free solvents. A positive and approximately linear relationship was found between the decrease in the HOMO/LUMO energy and the average binding energy between Li+ and the coordinated solvents. A binary-solvent complex model further highlight the significant importance of the electrolyte solvation environment in regulating electrolyte stability, and it is essential to consider electrolyte stability from the perspective of ion–solvent complexes. These fresh insights into the energy chemistry of multi-solvent complexes provide critical references for electrolyte design and cell optimization.展开更多
The continuous lithium consumption during cycling severely reduces the energy density of the lithium battery,and thus,lithium compensation is essential.Herein,Li_(x)C_(6)O_(6)(x=2,4)was proposed as an air-stable high-...The continuous lithium consumption during cycling severely reduces the energy density of the lithium battery,and thus,lithium compensation is essential.Herein,Li_(x)C_(6)O_(6)(x=2,4)was proposed as an air-stable high-efficiency sacrificial additive in the cathode to compensate for the lost lithium ions in solid-state lithium batteries.Below a delithiation(oxidation)potential as low as 3.8 V,Li_(2)C_(6)O_(6) can release most of its Li^(+)ions(294.8 mAh g^(−1) in theory).Similarly,Li_(4)C_(6)O_(6) is also characteristic of low oxidation potential and high delithiation capacity(547.8 mAh g^(−1) in theory).The feasibility of using Li_(x)C_(6)O_(6) as the self-sacrificial additive in the cathode was verified with the marked increase of the initial charge capacity of the Li||LiFePO_(4)(half)cells and the initial discharge capacity of Cu||LiFePO_(4)(full)cells,and the improved electrolyte/cathode interface stability and interface contact,in the solid-state poly(ethylene oxide)-lithium bis(trifluoromethane)sulfonimide(PEO-LiTFSI)electrolyte.In addition,the structure and delithiation of Li_(x)C_(6)O_(6) and the impacts of its decomposition product on the PEO-LiTFSI solid electrolyte were also evaluated on the basis of the comprehensive physical characterizations and the density functional theory(DFT)calculations.These findings open a new avenue for elevating the energy density and/or elongate the lifespan of the solid-state secondary batteries.展开更多
基金National Key Research and Development Program(2021YFB2500300)National Natural Science Foundation of China(T2322015,92472101,22393903,22393900,and 52394170)+2 种基金Beijing Municipal Natural Science Foundation(L247015 and L233004)Tsinghua University Initiative Scientific Research ProgramTsinghua Xuetang Talents Program of Tsinghua University。
文摘Lithium(Li)metal batteries hold great promise due to their high energy density,yet severe side reactions between routine organic electrolytes and the Li metal anode hinder their practical implementation.Elucidating the fundamental mechanisms that govern electrolyte stability on the Li metal anode is crucial to stabilizing the electrolyte-anode interface and promoting the practical applications of Li metal batteries.Herein,the regulation mechanism of the anode surface on the electrolyte stability is revealed at the atomic scale by density functional theory calculations.Indicated by the changes in the lowest unoccupied molecular orbital(LUMO)energy levels,solvents exhibit markedly lower reductive stability on Li metal surfaces compared with bulk molecules,making them more prone to parasitic reactions.Two major components in solid electrolyte interphase(SEI),i.e.,LiF and Li_(2)O,can passivate the solvent reduction through an average increase of 1.46 eV in their LUMO energy levels.The LUMO energy changes are further correlated with the Li-O distance between the solvents and SEI components,exhibiting an approximately linear relationship.This work reveals the role of the SEI in protecting Li metal anodes from electrolyte corrosion and identifies key factors regulating solvent stability,providing fundamental insights for the rational design of advanced electrolytes and robust SEI for practical Li metal batteries.
文摘The temperature stability of supercapacitor（SC） is largely determined by the properties of the electrolyte.Hydrogel electrolytes（HGE）, due to their hydrophilic polymer skeleton, show different temperature stability to that of liquid aqueous electrolytes. In this study, symmetric activated carbon（AC） SCs had been assembled with in situ electrodeposited poly（vinyl alcohol） potassium borate（PVAPB） HGE. The electrochemical performance of the SCs was systematically studied at different temperatures. Results show that the conductivity of PVAPB HGE is comparable with that of liquid aqueous electrolytes at different temperatures. The operating temperature range of PVAPB HGE SCs is -5–60°C, while those of the 1 mol/L Na2SO4SCs and the 0.9 mol/L KClSCs are 20–80°C and 20–40°C, respectively. The specific capacitance of PVAPB HGE SC is higher than those of SCs using liquid aqueous electrolytes at any temperature. The excellent temperature stability of PVAPB HGE makes it possible to build stable aqueous SCs in the wider temperature range.
基金supported by the National Key R&D Program of China(2022YFB2404700)the Natural Science Foundation of China(22109186)+1 种基金the Guangdong Innovative and Entrepreneurial Research Team Program(2021ZT09L227)supported by the Fundamental Research Funds for the Central Universities,Sun Yat-sen University(22hytd01)。
文摘Solid-state electrolytes(SSEs)play a pivotal role in advancing next-generation lithium metal battery technology.However,they commonly encounter substantial interfacial resistance and poor stability when interfacing with lithium metal,hindering practical applications.Herein,we introduce a flexible metal-organic framework(MOF:NUS-6)-incorporated polymeric layer,denoted as NP,designed to protect the sodium superionic conductor(NASICON)-type Li_(1.3)Al_(0.3)Ti_(1.7)(PO_(4))_(3)(LATP)electrolyte from Li metal anodes.The NP matrix establishes a soft interface with the LATP surface,effectively reducing voids and gaps that may arise between the LATP electrolyte and Li metal.Moreover,the MOF component in NP enhances ionic conductivity,offers abundant Li^(+)transport sites,and provides hierarchical ion channels,ensuring a homogeneous Li^(+)flow and thus effectively inhibiting Li dendrite formation.Utilizing NP,we fabricate Li symmetrical cells cycled for over 1600 h at 0.2 mA cm^(-2)and all-solid-state LiINP-LATPI LiFePO_(4)batteries,achieving a remarkable 99.3%capacity retention after 200 cycles at 0.2 C.This work outlines a general strategy for designing long-lasting and stable solid-state Li metal batteries.
基金Y.Sun acknowledges the financial support of the National Natural Science Foundation of China(No.52072137)Z.W.Seh acknowledges the support of the Singapore National Research Foundation(NRF-NRFF2017-04).
文摘A Li/KNO_(3) composite(LKNO),with KNO_(3) uniformly implanted in bulk metallic Li,is fabricated for battery anode via a facile mechanical kneading approach,which exhibits high Coulombic efficiency and prolonged cycle life.The mechanism behind the enhanced electrochemical performance of the“salt-in-metal”composite is investigated,where KNO_(3) in metallic Li composite electrode would be sustainably released into the electrolyte.The presence of NO_(3)-stabilizes the solid electrolyte interphase by producing functional Li_(3)N,LiNxOy,and Li_(2)O species.K^(+)from KNO_(3) also helps to form an electrostatic shield after its adsorption on the electrode protrusions,which suppresses the dendritic growth of metallic Li.With the above advantages,uniform Li plating with dense and planar structure is realized for the LKNO electrode.These findings reveal a deep understanding of the effect of the“saltin-metal”anode and provide new insights into the use of nitrate additives for high-energy-density Li metal batteries.
基金supported by the National Key Basic Research Program of China (No. 2014CB932303)the National Natural Science Foundation of China (No. 21573145)
文摘Non-aqueous lithium-oxygen （Li-O2） batteries have been considered as the superior energy storage system due to their high-energy density, however, some challenges limit the practical application of Li- O2 batteries. One of them is the lack of stable electrolyte. In this communication, a novel electrolyte with ethylene sulfite （ES） used as solvent for Li-O2 batteries was reported. ES solvent showed low volatility and high electrochemical stability. Without a catalyst in the air-electrode of Li-O2 batteries, the batteries showed high specific capacity, good round-trip efficiency and cycling stability.
基金the financial support from the Brazilian funding agencies CNPq(301486/2016-6)FAEPEX(2426/17)+7 种基金FAPESP(2020/04431-0,2020/04281-8,2016/25082-8,2017/11986-5,2017/11958-1,2014/02163-7,2018/20756-6,2018/02713-8)CAPES(1740195)the financial support from CNPq(Processes 131234/2020-0 and 130741/2021-3)the Fundação ao AmparoàPesquisa do Estado de Minas Gerais(FAPEMIGCNPq for the PQ-2 grant(Process 310544/20190)the support of Shell,the strategic importance of the support given by Brazil’s National Oil,Natural Gas,and Biofuels Agency(ANP)through the R&D levy regulationthe Center for Innovation on New Energies(CINE)the LNLS/CNPEM。
文摘Electrical double-layer capacitors(EDLCs)consist of energy storage devices that present high-power and moderate energy density.The electrolyte and electrode physicochemical properties are crucial for improving their overall energy storage capabilities.Therefore,the stability of the EDLCs’materials is the primary focus of this study.Since energy storage depends on the specific capacitance,and also on the square of the maximum capacitive cell voltage(UMCV).Thus,electrodes with high specific surface area(SSA)and electrolytes with excellent electrochemical stability are commonly reported in the literature.Aqueous electrolytes are safer and green devices compared to other organic-based solutions.On the other hand,their UMCVis reduced compared to other electrolytes(e.g.,organic-based and ionic liquids).In this sense,spanning the UMCVfor aqueous-based electrolytes is a’hot topic’research.Unfortunately,the lack of protocols to establish reliable UMCVvalues has culminated in the publishing of several conflicting results.Herein,we confirm that multiwalled carbon nanotubes(MWCNTs)housed in cells degrade and produce CO_(2) under abusive polarisation conditions.It is probed by employing electrochemical techniques,in-situ FTIR and in-situ Raman spectroscopies.From these considerations,the current study uses spectro-electrochemical techniques to support the correct determination of the electrode and electrolyte stability conditions as a function of the operating electrochemical parameters.
基金supported by the National Basic Research Program of China (No. 2014CB932303)National Natural ScienceFoundation of China (No. 21573145)
文摘A novel electrolyte with chloromethyl pivalate （CP） used as solvent was first reported for non-aqueous lithium-oxygen （Li-O2） batteries. Since there are no α-H atoms in the structure of CP, the CP based electrolyte in both superoxide radical solution and real LifO2 battery environment showed good chemical stability against superoxide radicals, which was confirmed by ^1H NMR and ^13C NMR measurements. Without a catalyst in the cathode of Li-O2 batteries, the batteries showed high specific capacity and cycling stability.
基金Korea Evaluation Institute of Industrial Technology(KEIT)and the Ministry of Trade,Industry&Energy(MOTIE)of the Republic of Korea(No.20020284)Materials&Components Technology Development(R&D)Program(No.00432124)funded by the Ministry of Trade,Industry&Energy(MOTIE,Korea)。
文摘The development of high-performance electrolyte-supported reversible solid oxide cells(RSOCs)is significantly hindered by the limitations of existing electrolyte materials,particularly in achieving high ionic conductivity and long-term stability under targeted operating conditions.While scandia stabilized zirconia(ScSZ)exhibits the highest ionic conductivity among zirconia-based electrolytes,ScSZ rapid conductivity degradation during prolonged operation remains a significant obstacle to commercialization.To address this pressing challenge,both binary and ternary co-doping were explored,incorporating Mg^(2+),In^(3+),Yb^(3+),and Sm^(3+)into the base composition of(Sc_(2)O_(3))_(0.11)(ZrO_(2))_(0.89)(11ScSZ).Among these,the optimized ternary co-doped composition,(In_(2)O_(3))_(0.0025)(Yb_(2)O_(3))_(0.0025)(Sc_(2)O_(3))_(0.11)(ZrO_(2))_(0.885)(0.25In0.25Yb11ScSZ),demonstrates significant enhancements in both ionic conductivity and stability.This ternary co-doped electrolyte exhibits superior conductivity and nearly double the stability of undoped 11ScSZ.In addition,it exhibits an enhanced flexural strength even higher than state-of-the-art electrolytes(161 MPa)and respectably wide electrolytic domain(10^(-16)-10^(-27)atm at 800℃).When implemented in 200μm-thick electrolyte-supported RSOC devices,the 0.25In0.25Yb11ScSZ electrolyte enables record-breaking performance,achieving a peak power density(PPD)of 1.02 W cm^(-2)in fuel cell(FC)mode and a current density of 1.05 A cm^(-2)at 1.3 V in electrolysis cell(EC)mode at 800℃both representing two-to three-fold improvement over state-of-the-art systems.These exceptional performance metrics,combined with excellent long-term durability,rank among the highest reported for electrolyte-supported cells,highlighting the potential of this novel ternary co-doped electrolyte for high-performance RSOC technologies capable of meeting the demanding requirements of next-generation energy systems.
基金The authors thank the funding support by National Natural Science Foundation of China(21875038 and 22005055)Joint Independent Innovation Fund of Tianjin University and Fuzhou University(TF2020-10)and Australian Research Council(DP180100731 and DP180100568).
文摘Reversible solid oxide cells(SOCs)are very efficient and clean for storage and regeneration of renewable electrical energy by switching between electrolysis and fuel cell modes.One of the most critical factors governing the efficiency and durability of SOCs technology is the stability of the interface between oxygen electrode and electrolyte,which is conventionally formed by sintering at a high temperature of~1000–1250℃,and which suffers from delamination problem,particularly for reversibly operated SOCs.On the other hand,our recent studies have shown that the electrode/electrolyte interface can be in situ formed by a direct assembly approach under the electrochemical polarization conditions at 800℃and lower.The direct assembly approach provides opportunities for significantly simplifying the cell fabrication procedures without the doped ceria barrier layer,enabling the utilization of a variety of high-performance oxygen electrode materials on barrier layer–free yttria-stabilized zirconia(YSZ)electrolyte.Most importantly,the in situ polarization induced interface shows a promising potential as highly active and durable interface for reversible SOCs.The objective of this progress report is to take an overview of the origin and research progress of in situ fabrication of oxygen electrodes based on the direct assembly approach.The prospect of direct assembly approach in the development of effective SOCs and in the fundamental studies of electrode/electrolyte interface reactions is discussed.
基金This work was supported by the National Natural Science Foundation of China(21825501)Beijing Municipal Natural Science Foundation(Z20J00043)+2 种基金National Key Research and Development Program(2016YFA0200102)Grant 2020GQG1006 from the Guoqiang Institute at Tsinghua UniversityX.Chen appreciates the support from the Shuimu Tsinghua Scholar Program of Tsinghua University and the Project funded by China Postdoctoral Science Foundation(2021TQ0161 and 2021M691709).
文摘The building of safe and high energy-density lithium batteries is strongly dependent on the electrochemical performance of working electrolytes, in which ion–solvent interactions play a vital role. Herein, the ion–solvent chemistry is developed from mono-solvent to multi-solvent complexes to probe the solvation structure and the redox stability of practical electrolytes. The decrease in energies of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) of solvents in lithium-ion solvation shells becomes less significant as the number of coordinated solvents increases, but both the HOMO and LUMO energies of the coordinated solvents remain lower than those of free solvents. A positive and approximately linear relationship was found between the decrease in the HOMO/LUMO energy and the average binding energy between Li+ and the coordinated solvents. A binary-solvent complex model further highlight the significant importance of the electrolyte solvation environment in regulating electrolyte stability, and it is essential to consider electrolyte stability from the perspective of ion–solvent complexes. These fresh insights into the energy chemistry of multi-solvent complexes provide critical references for electrolyte design and cell optimization.
基金financially supported by the National Natural Science Foundation of China(NSFC No.22075316,U23A20577,22005334,and 52172257)the Natural Science Foundation of Beijing(Grant No.Z200013).
文摘The continuous lithium consumption during cycling severely reduces the energy density of the lithium battery,and thus,lithium compensation is essential.Herein,Li_(x)C_(6)O_(6)(x=2,4)was proposed as an air-stable high-efficiency sacrificial additive in the cathode to compensate for the lost lithium ions in solid-state lithium batteries.Below a delithiation(oxidation)potential as low as 3.8 V,Li_(2)C_(6)O_(6) can release most of its Li^(+)ions(294.8 mAh g^(−1) in theory).Similarly,Li_(4)C_(6)O_(6) is also characteristic of low oxidation potential and high delithiation capacity(547.8 mAh g^(−1) in theory).The feasibility of using Li_(x)C_(6)O_(6) as the self-sacrificial additive in the cathode was verified with the marked increase of the initial charge capacity of the Li||LiFePO_(4)(half)cells and the initial discharge capacity of Cu||LiFePO_(4)(full)cells,and the improved electrolyte/cathode interface stability and interface contact,in the solid-state poly(ethylene oxide)-lithium bis(trifluoromethane)sulfonimide(PEO-LiTFSI)electrolyte.In addition,the structure and delithiation of Li_(x)C_(6)O_(6) and the impacts of its decomposition product on the PEO-LiTFSI solid electrolyte were also evaluated on the basis of the comprehensive physical characterizations and the density functional theory(DFT)calculations.These findings open a new avenue for elevating the energy density and/or elongate the lifespan of the solid-state secondary batteries.
