Progress in the fast charging of high-capacity silicon monoxide(SiO)-based anode is currently hindered by insufficient conductivity and notable volume expansion.The construction of an interface conductive network effe...Progress in the fast charging of high-capacity silicon monoxide(SiO)-based anode is currently hindered by insufficient conductivity and notable volume expansion.The construction of an interface conductive network effectively addresses the aforementioned problems;however,the impact of its quality on lithium-ion transfer and structure durability is yet to be explored.Herein,the influence of an interface conductive network on ionic transport and mechanical stability under fast charging is explored for the first time.2D modeling simulation and Cryo-transmission electron microscopy precisely reveal the mitigation of interface polarization owing to a higher fraction of conductive inorganic species formation in bilayer solid electrolyte interphase is mainly responsible for a linear decrease in ionic diffusion energy barrier.Furthermore,atomic force microscopy and Raman shift exhibit substantial stress dissipation generated by a complete conductive network,which is critical to the linear reduction of electrode residual stress.This study provides insights into the rational design of optimized interface SiO-based anodes with reinforced fast-charging performance.展开更多
Inorganic hole transport materials, particularly NiO_X, have shown considerable promise in boosting the efficiency and stability of perovskite solar cells. However, a major barrier to commercialization of NiO_X-based ...Inorganic hole transport materials, particularly NiO_X, have shown considerable promise in boosting the efficiency and stability of perovskite solar cells. However, a major barrier to commercialization of NiO_X-based perovskite solar cells with positive-intrinsic-negative architectures is their direct contact with the absorbing layer, which can lead to losses of photovoltage and fill factor. Furthermore, highly positive under-coordinated Ni cations degrade the perovskite at the interface. Here, we address these issues with the use of an ionic compound(QAPyBF_(4)) as an additive to passivate defects throughout the perovskite layer and improve carrier conduction and interactions with under-coordinated Ni cations. Specifically,the highly electronegative inorganic anion [BF_(4)]~- interacts with the NiO_x/perovskite interface to passivate under-coordinated cations(Ni^(≥3+)). Accordingly, the decorated cells achieved a power conversion efficiency of 23.38% and a fill factor of 85.5% without a complex surface treatment or NiO_X doping.展开更多
Interfacial defects and energy barrier would result in serious interfacial non-radiative recombination losses.In addition,the quality of perovskite films is highly dependent on deposition substrates.Consequently,there...Interfacial defects and energy barrier would result in serious interfacial non-radiative recombination losses.In addition,the quality of perovskite films is highly dependent on deposition substrates.Consequently,there is an urgent desire to develop multifunctional interface modulators to manage the interface between electron transport layer and perovskite layer.Here,we report a multifunctional buried interface modulation strategy that 4-fluoro-phenylammonium tetrafluoroborate (FBABF_(4)) consisting of simultaneously fluorinated anion and cation is inserted between SnO_(2)layer and perovskite layer.It is uncovered by time-of-flight secondary ion mass spectroscopy that the anion and cation in modifier are mainly located at this interface,which is put down to coordination bond of the fluorine atom on BF_(4)^(-) with SnO_(2),and the hydrogen bond of the fluorine atom on FBA^(+) with formamidinium.This suggests that simultaneous fluorination of anion and cation in the ionic liquid molecule is of crucial importance to ameliorate interfacial contact through chemical linker.The interface modification approach enables the realization of interfacial defect passivation,interfacial energy band alignment modulation,and perovskite crystallization manipulation,which are translated into enhanced efficiency and stability as well as significantly suppressed hysteresis.The multiple functions of FBABF_(4) endow the modified solar cells excellent photovoltaic performance with an efficiency exceeding 23%along with appealing long-term stability.This work highlights the critical role of fluorination strategy in engineering multifunctional organic salt modulators for improving interfacial contact.展开更多
How to completely remove the water from ionic liquids(ILs)is difficult for researchers because of the hygroscopicity of ILs.In order to study the hygroscopicity of ILs,two kinds of ILs,1-Butyl-3-methylimidazolium hexa...How to completely remove the water from ionic liquids(ILs)is difficult for researchers because of the hygroscopicity of ILs.In order to study the hygroscopicity of ILs,two kinds of ILs,1-Butyl-3-methylimidazolium hexafluorophosphate([Bmim][PF6])and 1-Butyl-3-methylimidazolium Bis(trifluoromethanesulfonyl)([Bmim][NTf_(2)])were investigated by molecular dynamics simulations.Although[Bmim][PF6]and[Bmim][NTf_(2)]are hydrophobic,both of the ILs could absorb water molecules from the vapor.In this work,the process of absorbing water from the vapor phase was studied,and the water molecules could disperse into the IL.Aggregation was observed with increasing the water concentration.Although the absorbed water increases obviously,the amount of free water and small cluster in the ILs does not change significantly and always stays at a certain level.The amount of free water and small cluster in[Bmim][PF6]is more than that in[Bmim][NTf_(2)],which is consistent with their hydrophobicity.In addition,the liquid-vacuum and liquid–liquid interfaces of the ILs were simulated and analyzed in detail.The number density distribution and angle distribution indicated that[Bmim]+cations arrangement regularly at the IL-vacuum interface.The butyl chain point to the vacuum,while the imidazlium ring is close to the IL phase region and perpendicular to the interface.While at the IL-water interface,the cations and anions are disordered.展开更多
Although ionic liquids(ILs)have been widely employed to heal the defects in perovskite solar cells(PSCs),the corresponding defect passivation mechanisms are not thoroughly understood up to now.Herein,we first reveal a...Although ionic liquids(ILs)have been widely employed to heal the defects in perovskite solar cells(PSCs),the corresponding defect passivation mechanisms are not thoroughly understood up to now.Herein,we first reveal an abnormal buried interface anion defect passivation mechanism depending on cationinduced steric hindrance.The IL molecules containing the same anion([BF4]^(-))and different sizes of imidazolium cations induced by substituent size are used to manipulate buried interface.It was revealed what passivated interfacial defects is mainly anions instead of cations.Theoretical and experimental results demonstrate that the large-sized cations can weaken the ionic bond strength between anions and cations,and facilitate the interaction between anions and SnO2as well as perovskites,which is conducive to interfacial defect passivation and ameliorating interfacial contact.It can be concluded that interfacial chemical interaction strength and defect passivation effect are positively correlated with the size of cations.The discovery breaks conventional thinking that large-sized modification molecules would weaken their chemical interaction with perovskite.Compared with the control device(21.54%),the device based on 1,3-Bis(1-adamantyl)-imidazolium tetrafluoroborate(BAIMBF4)with maximum size cations achieves a significantly enhanced efficiency of 23.61%along with much increased moisture,thermal and light stabilities.展开更多
The watermiscible room temperature ionic liquid 1butyl3methylimidazolium tetrafluorob orate （[bmim] [BF4]） is a model system for studying the interactions between ionic liquid and water molecules. In this work the o...The watermiscible room temperature ionic liquid 1butyl3methylimidazolium tetrafluorob orate （[bmim] [BF4]） is a model system for studying the interactions between ionic liquid and water molecules. In this work the orientational structure of the low concentrated aqueous solution of [bmim] [BF4] at the air/liquid interface was investigated by sum frequency gener ation vibrational spectroscopy. It has been found that at very low concentrations, the butyl chain exhibited a significant gauche defect, indicating a disordered conformation; and the cation ring oriented with a fairly small tilting angle at the surface. When the concentration increased, the cation ring tended to lie flat at the surface, and the gauche defects of the butyl chain decreased due to the intermolecular chainchain interactions and the consequent more ordered interfacial molecular arrangement. Additionally, the antisymmetric stretching mode in the PPP and SPS spectra exhibited a peak shift, showing that there exists more than one kind of orientation or chemical environment for the butyl CH3 group. These results may shed new light on understanding the surface behavior of watermiscible ionic liquids as well as the imidazolium based surfactants.展开更多
Li/garnet/LiFePO_(4) solid-state battery was fabricated.The cathode contains LiFePO_(4),Ketjen black,poly(vinylidene fluoride):LiTFSI polymer as active material,electric conductor and Li-ion conducting binder,respecti...Li/garnet/LiFePO_(4) solid-state battery was fabricated.The cathode contains LiFePO_(4),Ketjen black,poly(vinylidene fluoride):LiTFSI polymer as active material,electric conductor and Li-ion conducting binder,respectively.Polyvinylpyrrolidone was added into the cathode to improve cathode/electrolyte interfacial performance.When combined with polyvinylpyrrolidone additive,poly(vinylidene fluoride):polyvinylpyrrol idone:LiTFSI blend forms,and the cathode/electrolyte interfacial resistance reduces from 10.7 kΩto 3.2 kΩ.The Li/garnet/LiFePO_(4) solid-state battery shows 80%capacity retention after 100 cycles at 30℃and 0.05 C.This study offers a general strategy to improve cathode/electrolyte interfacial performance and may enable the practical application of solid-state Li-metal batteries.展开更多
Metal halide perovskite solar cells(PSCs)have shown great potential to become the next generation of photovoltaic devices due to their simple fabrication techniques,low cost,and soaring power conversion efficiency(PCE...Metal halide perovskite solar cells(PSCs)have shown great potential to become the next generation of photovoltaic devices due to their simple fabrication techniques,low cost,and soaring power conversion efficiency(PCE).However,mismatched with the quickly updated PCEs,the improvement of device stability is challenging and still remains a critical hurdle in the path to commercialization.Recently,ionic liquids(ILs)have been found to play multiple roles in obtaining efficient and stable PSCs.These ILs usually consist of large organic cations and organic or inorganic anions,which have weak electrostatic attraction and are generally liquid at around 100℃.ILs are almost non-volatile,non-flammable,with high ionic conductivity and excellent thermal and electrochemical stability.The roles of ILs in PSCs vary with their composition,that is,the types of anions and cations.In this review,we summarize the roles of anions and cations in terms of precursor solutions,additives,perovskite/charge transport layer interface engineering,and charge transport layers.This article aims to set up a structure–property-stability-performance correlations conferred by the IL in PSC and provide assistance for the anion and cation selection for improving the quality of perovskite film,optimizing interface contact,reducing defect states,and improving charge extraction and transport characteristics.Finally,the application of IL in PSCs is discussed and prospected.展开更多
Solid-aqueous interfaces and phenomena occurring at those interfaces are ubiquitously found in a plethora of chemical systems.When it comes to heterogeneous catalysis,however,our understanding of chemical transformati...Solid-aqueous interfaces and phenomena occurring at those interfaces are ubiquitously found in a plethora of chemical systems.When it comes to heterogeneous catalysis,however,our understanding of chemical transformations at solid-aqueous interfaces is relatively limited and primitive.This review phenomenologically describes a selection of water-engendered effects on the catalytic behavior for several prototypical acid-base-catalyzed reactions over solid catalysts,and critically assesses the general and special roles of water molecules,structural moieties derived from water,and ionic species that are dissolved in it,with an aim to extract novel concepts and principles that underpin heterogeneous acid-base catalysis in the aqueous phase.For alcohol dehydration catalyzed by solid Bronsted acids,rate inhibition by water is most typically related to the decrease in the acid strength and/or the preferential solvation of adsorbed species over the transition state as water molecules progressively solvate the acid site and form extended networks wherein protons are mobilized.Water also inhibits dehydration kinetics over most Lewis acid-base catalysts by competitive adsorption,but a few scattered reports reveal substantial rate enhancements due to the conversion of Lewis acid sites to Brønsted acid sites with higher catalytic activities upon the introduction of water.For aldol condensation on catalysts exposing Lewis acid-base pairs,the addition of water is generally observed to enhance the rate when C–C coupling is rate-limiting,but may result in rate inhibition by site-blocking when the initial unimolecular deprotonation is rate-limiting.Water can also promote aldol condensation on Brønsted acidic catalysts by facilitating inter-site communication between acid sites through hydrogen-bonding interactions.For metallozeolite-catalyzed sugar isomerization in aqueous media,the nucleation and networking of intrapore waters regulated by hydrophilic entities causes characteristic enthalpy-entropy tradeoffs as these water moieties interact with kinetically relevant hydride transfer transition states.The discussed examples collectively highlight the utmost importance of hydrogen-bonding interactions and ionization of covalently bonded surface moieties as the main factors underlying the uniqueness of water-mediated interfacial acid-base chemistries and the associated solvation effects in the aqueous phase or in the presence of water.A perspective is also provided for future research in this vibrant field.展开更多
The energy barrier at the CH3NH3Pb Br3/TiO2interface hinders the electron transfer from CH3NH3Pb Br3to compact TiO2（cp-TiO2）.Ionic liquid（IL）,that forms dipoles pointing away from TiO2,can adjust the work function...The energy barrier at the CH3NH3Pb Br3/TiO2interface hinders the electron transfer from CH3NH3Pb Br3to compact TiO2（cp-TiO2）.Ionic liquid（IL）,that forms dipoles pointing away from TiO2,can adjust the work function of TiO2resulting in suitable energy level for charge transfer from CH3NH3Pb Br3to TiO2.The time-resolved photoluminescence spectroscopy（TRPL）measurements confirm faster electron transfer from the CH3NH3Pb Br3film to TiO2after modification by IL.Solar cells based on IL modified cp-TiO2demonstrate efficiency of～6%,much higher than the devices（0.2%）fabricated using untreated cp-TiO2as the electron transport layer.展开更多
Perovskite solar cells(PSCs)have attracted much attention due to their rapidly increased power conversion efficiencies,however,their inherent poor long-term stability hinders their commercialization.The degradation of...Perovskite solar cells(PSCs)have attracted much attention due to their rapidly increased power conversion efficiencies,however,their inherent poor long-term stability hinders their commercialization.The degradation of PSCs first comes from the degradation of hole transport materials(HTMs).Here,we report the construction of periodicπ-columnar arrays and ionic interfaces over the skeletons by introducing cationic covalent organic frameworks(C-COFs)to the HTM.Periodicπ-columnar arrays can optimize the charge transport ability and energy levels of the hole transport layer and suppress the degradation of HTM,and ionic interfaces over the skeletons can produce stronger electric dipole and electrostatic interactions,as well as higher charge densities.The C-COFs were designed and synthesized via Schiff base reaction by using 1,3,5-triformylphloroglucinol as a neutral knot and dimidium bromide as cationic linker.The neutral COFs(N-COFs)were also synthesized as a reference by using 3,8-diamino-6-phenylphenanthridine as neutral linker.PSCs with cationic COF exhibit the highest efficiency of 23.4%with excellent humidity and thermal stability.To the best of our knowledge,this is the highest efficiency among the meso-structured PSCs fabricated by a sequential process.展开更多
The pursuit of high energy density has promoted the development of high-performance lithium metal batteries.However,it faces a serious security problem.Ionic liquids have attracted great attention due to their high io...The pursuit of high energy density has promoted the development of high-performance lithium metal batteries.However,it faces a serious security problem.Ionic liquids have attracted great attention due to their high ionic conductivity,non-flammability,and the properties of promoting the formation of stable SEI films.Deeply understanding the problems existing in lithium metal batteries and the role of ionic liquids in them is of great significance for improving the performance of lithium metal batteries.This article reviews the effects of the molecular structure of ionic liquids on ionic conductivity,Li^(+)ion transference number,electrochemical stability window,and lithium metal anode/electrolyte interface,as well as the application of ionic liquids in Li-high voltage cathode batteries,Li-O_(2) batteries and Li-S batteries.The molecular design,composition and polymerization will be the main strategies for the future development of ionic liquid-based electrolytes for high performance lithium metal battery.展开更多
Physical models of ion diffusion at different interfaces are reviewed. The use of impedance spectroscopy （IS）, nuclear magnetic resonance （NMR）, and secondary ion mass spectrometry （SIMS） techniques are also dis...Physical models of ion diffusion at different interfaces are reviewed. The use of impedance spectroscopy （IS）, nuclear magnetic resonance （NMR）, and secondary ion mass spectrometry （SIMS） techniques are also discussed. The diffusion of ions is fundamental to the operation of lithium-ion batteries, taking place not only within the grains but also across different interfaces. Interfacial ion transport usually contributes to the majority of the resistance in lithium-ion batteries. A greater understanding of the interfacial diffusion of ions is crucial to improving battery performance.展开更多
Interface engineering is an effective way to improve efficiency and long-term stability of perovskite solar cells(PSCs).Herein,an ionic compound tetrabutylammonium hexafluorophosphate(TP6)is adopted to passivate surfa...Interface engineering is an effective way to improve efficiency and long-term stability of perovskite solar cells(PSCs).Herein,an ionic compound tetrabutylammonium hexafluorophosphate(TP6)is adopted to passivate surface defects of the perovskite film.It is found that TP6 effectively reduced the surface defects,especially at the grain boundaries where the defects are abundant.Meanwhile,the exposed long alkyl chains and fluorine atoms in the TP6 enhanced the moisture stability of the perovskite film due to its strong hydrophobicity.In addition,the driving force of charge carrier separation and transport is increased by enlarged built-in potential.Consequently,the power conversion efficiency(PCE)of PSCs is significantly improved from 20.59% to 22.41%by increased open-circuit voltage(V_(oc))and fill factor(FF).The unencapsulated device with TP6 treatment exhibits better stability than the control device,and the PCE retains-80%of its initial PCE after 30 days under 15%-25%relative humidity in storage,while the PCE of the control device declines by more than 50%.展开更多
基金the National Natural Science Foundation of China(Nos.22209095 and 22238004).
文摘Progress in the fast charging of high-capacity silicon monoxide(SiO)-based anode is currently hindered by insufficient conductivity and notable volume expansion.The construction of an interface conductive network effectively addresses the aforementioned problems;however,the impact of its quality on lithium-ion transfer and structure durability is yet to be explored.Herein,the influence of an interface conductive network on ionic transport and mechanical stability under fast charging is explored for the first time.2D modeling simulation and Cryo-transmission electron microscopy precisely reveal the mitigation of interface polarization owing to a higher fraction of conductive inorganic species formation in bilayer solid electrolyte interphase is mainly responsible for a linear decrease in ionic diffusion energy barrier.Furthermore,atomic force microscopy and Raman shift exhibit substantial stress dissipation generated by a complete conductive network,which is critical to the linear reduction of electrode residual stress.This study provides insights into the rational design of optimized interface SiO-based anodes with reinforced fast-charging performance.
基金supported by the National Key Research and Development Project from the Ministry of Science and Technology of China (No. 2021YFB3800103)National Natural Science Foundation of China (22209068)+1 种基金General Program of Basic Research in Shenzhen (JCYJ20220530112801004)the Major Program of Guangdong Basic and Applied Research Foundation (Nos. 2019B1515120083, 2019B121205001 and 2019B030302009)。
文摘Inorganic hole transport materials, particularly NiO_X, have shown considerable promise in boosting the efficiency and stability of perovskite solar cells. However, a major barrier to commercialization of NiO_X-based perovskite solar cells with positive-intrinsic-negative architectures is their direct contact with the absorbing layer, which can lead to losses of photovoltage and fill factor. Furthermore, highly positive under-coordinated Ni cations degrade the perovskite at the interface. Here, we address these issues with the use of an ionic compound(QAPyBF_(4)) as an additive to passivate defects throughout the perovskite layer and improve carrier conduction and interactions with under-coordinated Ni cations. Specifically,the highly electronegative inorganic anion [BF_(4)]~- interacts with the NiO_x/perovskite interface to passivate under-coordinated cations(Ni^(≥3+)). Accordingly, the decorated cells achieved a power conversion efficiency of 23.38% and a fill factor of 85.5% without a complex surface treatment or NiO_X doping.
基金supported by the National Natural Science Foundation of China (Grant Nos. 62004058, U21A2076, 21701041, 52071048)the Nature Science Foundation of Hebei Province (Grant No. F2020202022)+4 种基金the Open Fund of the State Key Laboratory of Integrated Optoelectronics (Grant No. IOSKL2020KF09)the State Key Laboratory of Reliability and Intelligence of Electrical Equipment (Grant No. EERI_PI20200005)supported by the Support plan for Overseas Students to Return to China for Entrepreneurship and Innovation (Grant No. cx2020003)the Fundamental Research Funds for the Central Universities (Grant No. 2020CDJ-LHZZ-074)the Natural Science Foundation of Chongqing (Grant No. cstc2020jcyjmsxmX0629)。
文摘Interfacial defects and energy barrier would result in serious interfacial non-radiative recombination losses.In addition,the quality of perovskite films is highly dependent on deposition substrates.Consequently,there is an urgent desire to develop multifunctional interface modulators to manage the interface between electron transport layer and perovskite layer.Here,we report a multifunctional buried interface modulation strategy that 4-fluoro-phenylammonium tetrafluoroborate (FBABF_(4)) consisting of simultaneously fluorinated anion and cation is inserted between SnO_(2)layer and perovskite layer.It is uncovered by time-of-flight secondary ion mass spectroscopy that the anion and cation in modifier are mainly located at this interface,which is put down to coordination bond of the fluorine atom on BF_(4)^(-) with SnO_(2),and the hydrogen bond of the fluorine atom on FBA^(+) with formamidinium.This suggests that simultaneous fluorination of anion and cation in the ionic liquid molecule is of crucial importance to ameliorate interfacial contact through chemical linker.The interface modification approach enables the realization of interfacial defect passivation,interfacial energy band alignment modulation,and perovskite crystallization manipulation,which are translated into enhanced efficiency and stability as well as significantly suppressed hysteresis.The multiple functions of FBABF_(4) endow the modified solar cells excellent photovoltaic performance with an efficiency exceeding 23%along with appealing long-term stability.This work highlights the critical role of fluorination strategy in engineering multifunctional organic salt modulators for improving interfacial contact.
基金financial support from the National Science Fund for Excellent Young Scholars(21722610)Taishan Scholars Program of Shandong Province(tsqn201909091)。
文摘How to completely remove the water from ionic liquids(ILs)is difficult for researchers because of the hygroscopicity of ILs.In order to study the hygroscopicity of ILs,two kinds of ILs,1-Butyl-3-methylimidazolium hexafluorophosphate([Bmim][PF6])and 1-Butyl-3-methylimidazolium Bis(trifluoromethanesulfonyl)([Bmim][NTf_(2)])were investigated by molecular dynamics simulations.Although[Bmim][PF6]and[Bmim][NTf_(2)]are hydrophobic,both of the ILs could absorb water molecules from the vapor.In this work,the process of absorbing water from the vapor phase was studied,and the water molecules could disperse into the IL.Aggregation was observed with increasing the water concentration.Although the absorbed water increases obviously,the amount of free water and small cluster in the ILs does not change significantly and always stays at a certain level.The amount of free water and small cluster in[Bmim][PF6]is more than that in[Bmim][NTf_(2)],which is consistent with their hydrophobicity.In addition,the liquid-vacuum and liquid–liquid interfaces of the ILs were simulated and analyzed in detail.The number density distribution and angle distribution indicated that[Bmim]+cations arrangement regularly at the IL-vacuum interface.The butyl chain point to the vacuum,while the imidazlium ring is close to the IL phase region and perpendicular to the interface.While at the IL-water interface,the cations and anions are disordered.
基金financially supported by the Support Plan for Overseas Students to Return to China for Entrepreneurship and Innovation(cx2020003)the Fundamental Research Funds for the Central Universities(2020CDJ-LHZZ-074 and 2021CDJQY-022)Natural Science Foundation of Chongqing(cstc2020jcyjmsxmX0629)。
文摘Although ionic liquids(ILs)have been widely employed to heal the defects in perovskite solar cells(PSCs),the corresponding defect passivation mechanisms are not thoroughly understood up to now.Herein,we first reveal an abnormal buried interface anion defect passivation mechanism depending on cationinduced steric hindrance.The IL molecules containing the same anion([BF4]^(-))and different sizes of imidazolium cations induced by substituent size are used to manipulate buried interface.It was revealed what passivated interfacial defects is mainly anions instead of cations.Theoretical and experimental results demonstrate that the large-sized cations can weaken the ionic bond strength between anions and cations,and facilitate the interaction between anions and SnO2as well as perovskites,which is conducive to interfacial defect passivation and ameliorating interfacial contact.It can be concluded that interfacial chemical interaction strength and defect passivation effect are positively correlated with the size of cations.The discovery breaks conventional thinking that large-sized modification molecules would weaken their chemical interaction with perovskite.Compared with the control device(21.54%),the device based on 1,3-Bis(1-adamantyl)-imidazolium tetrafluoroborate(BAIMBF4)with maximum size cations achieves a significantly enhanced efficiency of 23.61%along with much increased moisture,thermal and light stabilities.
文摘The watermiscible room temperature ionic liquid 1butyl3methylimidazolium tetrafluorob orate （[bmim] [BF4]） is a model system for studying the interactions between ionic liquid and water molecules. In this work the orientational structure of the low concentrated aqueous solution of [bmim] [BF4] at the air/liquid interface was investigated by sum frequency gener ation vibrational spectroscopy. It has been found that at very low concentrations, the butyl chain exhibited a significant gauche defect, indicating a disordered conformation; and the cation ring oriented with a fairly small tilting angle at the surface. When the concentration increased, the cation ring tended to lie flat at the surface, and the gauche defects of the butyl chain decreased due to the intermolecular chainchain interactions and the consequent more ordered interfacial molecular arrangement. Additionally, the antisymmetric stretching mode in the PPP and SPS spectra exhibited a peak shift, showing that there exists more than one kind of orientation or chemical environment for the butyl CH3 group. These results may shed new light on understanding the surface behavior of watermiscible ionic liquids as well as the imidazolium based surfactants.
基金Funded by the National Natural Science Foundation of China(Nos.51772314,51532002,51771222 and 51702346)the Natural Science Foundation of Shanghai City(17ZR1434600)。
文摘Li/garnet/LiFePO_(4) solid-state battery was fabricated.The cathode contains LiFePO_(4),Ketjen black,poly(vinylidene fluoride):LiTFSI polymer as active material,electric conductor and Li-ion conducting binder,respectively.Polyvinylpyrrolidone was added into the cathode to improve cathode/electrolyte interfacial performance.When combined with polyvinylpyrrolidone additive,poly(vinylidene fluoride):polyvinylpyrrol idone:LiTFSI blend forms,and the cathode/electrolyte interfacial resistance reduces from 10.7 kΩto 3.2 kΩ.The Li/garnet/LiFePO_(4) solid-state battery shows 80%capacity retention after 100 cycles at 30℃and 0.05 C.This study offers a general strategy to improve cathode/electrolyte interfacial performance and may enable the practical application of solid-state Li-metal batteries.
基金financial support from the National Natural Science Foundation of China(22075094)the Fundamental Research Funds for the Central Universities。
文摘Metal halide perovskite solar cells(PSCs)have shown great potential to become the next generation of photovoltaic devices due to their simple fabrication techniques,low cost,and soaring power conversion efficiency(PCE).However,mismatched with the quickly updated PCEs,the improvement of device stability is challenging and still remains a critical hurdle in the path to commercialization.Recently,ionic liquids(ILs)have been found to play multiple roles in obtaining efficient and stable PSCs.These ILs usually consist of large organic cations and organic or inorganic anions,which have weak electrostatic attraction and are generally liquid at around 100℃.ILs are almost non-volatile,non-flammable,with high ionic conductivity and excellent thermal and electrochemical stability.The roles of ILs in PSCs vary with their composition,that is,the types of anions and cations.In this review,we summarize the roles of anions and cations in terms of precursor solutions,additives,perovskite/charge transport layer interface engineering,and charge transport layers.This article aims to set up a structure–property-stability-performance correlations conferred by the IL in PSC and provide assistance for the anion and cation selection for improving the quality of perovskite film,optimizing interface contact,reducing defect states,and improving charge extraction and transport characteristics.Finally,the application of IL in PSCs is discussed and prospected.
文摘Solid-aqueous interfaces and phenomena occurring at those interfaces are ubiquitously found in a plethora of chemical systems.When it comes to heterogeneous catalysis,however,our understanding of chemical transformations at solid-aqueous interfaces is relatively limited and primitive.This review phenomenologically describes a selection of water-engendered effects on the catalytic behavior for several prototypical acid-base-catalyzed reactions over solid catalysts,and critically assesses the general and special roles of water molecules,structural moieties derived from water,and ionic species that are dissolved in it,with an aim to extract novel concepts and principles that underpin heterogeneous acid-base catalysis in the aqueous phase.For alcohol dehydration catalyzed by solid Bronsted acids,rate inhibition by water is most typically related to the decrease in the acid strength and/or the preferential solvation of adsorbed species over the transition state as water molecules progressively solvate the acid site and form extended networks wherein protons are mobilized.Water also inhibits dehydration kinetics over most Lewis acid-base catalysts by competitive adsorption,but a few scattered reports reveal substantial rate enhancements due to the conversion of Lewis acid sites to Brønsted acid sites with higher catalytic activities upon the introduction of water.For aldol condensation on catalysts exposing Lewis acid-base pairs,the addition of water is generally observed to enhance the rate when C–C coupling is rate-limiting,but may result in rate inhibition by site-blocking when the initial unimolecular deprotonation is rate-limiting.Water can also promote aldol condensation on Brønsted acidic catalysts by facilitating inter-site communication between acid sites through hydrogen-bonding interactions.For metallozeolite-catalyzed sugar isomerization in aqueous media,the nucleation and networking of intrapore waters regulated by hydrophilic entities causes characteristic enthalpy-entropy tradeoffs as these water moieties interact with kinetically relevant hydride transfer transition states.The discussed examples collectively highlight the utmost importance of hydrogen-bonding interactions and ionization of covalently bonded surface moieties as the main factors underlying the uniqueness of water-mediated interfacial acid-base chemistries and the associated solvation effects in the aqueous phase or in the presence of water.A perspective is also provided for future research in this vibrant field.
基金the financial support from the Institute for Critical Technology and Applied Science(ICTAS)the financial support from Office of Naval Research(I.Perez)through grant number N000141613043the supports of National Natural Science Foundation of China under grant no.61604152
文摘The energy barrier at the CH3NH3Pb Br3/TiO2interface hinders the electron transfer from CH3NH3Pb Br3to compact TiO2（cp-TiO2）.Ionic liquid（IL）,that forms dipoles pointing away from TiO2,can adjust the work function of TiO2resulting in suitable energy level for charge transfer from CH3NH3Pb Br3to TiO2.The time-resolved photoluminescence spectroscopy（TRPL）measurements confirm faster electron transfer from the CH3NH3Pb Br3film to TiO2after modification by IL.Solar cells based on IL modified cp-TiO2demonstrate efficiency of～6%,much higher than the devices（0.2%）fabricated using untreated cp-TiO2as the electron transport layer.
基金This work was supported by the National Natural Science Foundation of China(No.52203359)Fundamental Research Funds for the Central Universities(No.NS2022092)+5 种基金National Key Research and Development Program of China(No.2019YFA0705400)Natural Science Foundation of Jiangsu Province(No.BK20212008)the Research Fund of State Key Laboratory of Mechanics and Control of Mechanical Structures(Nos.MCMS-I-0421K01 and MCMS-I-0422K01)the Fundamental Research Funds for the Central Universities(No.NJ2022002)the National Natural Science Foundation of China(Nos.52073119 and 21774040)A Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions.
文摘Perovskite solar cells(PSCs)have attracted much attention due to their rapidly increased power conversion efficiencies,however,their inherent poor long-term stability hinders their commercialization.The degradation of PSCs first comes from the degradation of hole transport materials(HTMs).Here,we report the construction of periodicπ-columnar arrays and ionic interfaces over the skeletons by introducing cationic covalent organic frameworks(C-COFs)to the HTM.Periodicπ-columnar arrays can optimize the charge transport ability and energy levels of the hole transport layer and suppress the degradation of HTM,and ionic interfaces over the skeletons can produce stronger electric dipole and electrostatic interactions,as well as higher charge densities.The C-COFs were designed and synthesized via Schiff base reaction by using 1,3,5-triformylphloroglucinol as a neutral knot and dimidium bromide as cationic linker.The neutral COFs(N-COFs)were also synthesized as a reference by using 3,8-diamino-6-phenylphenanthridine as neutral linker.PSCs with cationic COF exhibit the highest efficiency of 23.4%with excellent humidity and thermal stability.To the best of our knowledge,this is the highest efficiency among the meso-structured PSCs fabricated by a sequential process.
基金the National Natural Science Foundation of China(21503131 and 51711530162)the Shanghai Municipal Science and Technology Commission(19640770300)+2 种基金the Shanghai Engineering Research Center of New Materials and Application for Resources and Environment(18DZ2281400)the Professional and Technical Service Platform for Designing and Manufacturing of Advanced Composite Materials(Shanghai)(19DZ2293100)the Engineering Research Center of Material Composition and Advanced Dispersion Technology,Ministry of Education。
文摘The pursuit of high energy density has promoted the development of high-performance lithium metal batteries.However,it faces a serious security problem.Ionic liquids have attracted great attention due to their high ionic conductivity,non-flammability,and the properties of promoting the formation of stable SEI films.Deeply understanding the problems existing in lithium metal batteries and the role of ionic liquids in them is of great significance for improving the performance of lithium metal batteries.This article reviews the effects of the molecular structure of ionic liquids on ionic conductivity,Li^(+)ion transference number,electrochemical stability window,and lithium metal anode/electrolyte interface,as well as the application of ionic liquids in Li-high voltage cathode batteries,Li-O_(2) batteries and Li-S batteries.The molecular design,composition and polymerization will be the main strategies for the future development of ionic liquid-based electrolytes for high performance lithium metal battery.
基金supported by the Beijing S&T Project,China(Grant No.Z13111000340000)the National Natural Science Foundation of China(Grant Nos.51325206and 11234013)the National Basic Research Program of China(Grant No.2012CB932900)
文摘Physical models of ion diffusion at different interfaces are reviewed. The use of impedance spectroscopy （IS）, nuclear magnetic resonance （NMR）, and secondary ion mass spectrometry （SIMS） techniques are also discussed. The diffusion of ions is fundamental to the operation of lithium-ion batteries, taking place not only within the grains but also across different interfaces. Interfacial ion transport usually contributes to the majority of the resistance in lithium-ion batteries. A greater understanding of the interfacial diffusion of ions is crucial to improving battery performance.
基金funded by the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDA17040506)the National Key Research and Development Program of China (2017YFA0204800/2016YFA0202403)+6 种基金the Key Program project of the National Natural Science Foundation of China (51933010)the National Natural Science Foundation of China (61974085)the 111 Project (B21005)the Changjiang Scholars and Innovative Research Team (IRT_14R33)the National University Research Fund (GK201903051)the Research Start-up Fund from Shaanxi Normal University (1110020142)the Shanxi Science and Technology Department (20201101012).
文摘Interface engineering is an effective way to improve efficiency and long-term stability of perovskite solar cells(PSCs).Herein,an ionic compound tetrabutylammonium hexafluorophosphate(TP6)is adopted to passivate surface defects of the perovskite film.It is found that TP6 effectively reduced the surface defects,especially at the grain boundaries where the defects are abundant.Meanwhile,the exposed long alkyl chains and fluorine atoms in the TP6 enhanced the moisture stability of the perovskite film due to its strong hydrophobicity.In addition,the driving force of charge carrier separation and transport is increased by enlarged built-in potential.Consequently,the power conversion efficiency(PCE)of PSCs is significantly improved from 20.59% to 22.41%by increased open-circuit voltage(V_(oc))and fill factor(FF).The unencapsulated device with TP6 treatment exhibits better stability than the control device,and the PCE retains-80%of its initial PCE after 30 days under 15%-25%relative humidity in storage,while the PCE of the control device declines by more than 50%.
