In this work, the effect of octane concentration on the phase behavior of CTAB/water/1-butanol system was studied by using pulsed field gradient spin-echo NMR measurements and freeze fracture electron microscopy (Cryo...In this work, the effect of octane concentration on the phase behavior of CTAB/water/1-butanol system was studied by using pulsed field gradient spin-echo NMR measurements and freeze fracture electron microscopy (Cryo-TEM and FFEM). When the octane concentration increases, the liquid crystalline phase is destabilized and a continuous single-phase microemulsion region from the water apex to the oil apex is formed. The conductivity behavior has a distinct percolative phenomenon, which indicates that the single-phase microemulsion is changed continuously from oil-in-water (o/w) structure via a bicontinuous structure to wa-ter-in-oil (w/o) structure. This result is consistent with those of the PGSE-NMR, Cryo-TEM, and FFEM. In the w/o region, the self-diffusion coefficient of water is relatively high ((1-6) ×1(T-10 m . s-1) due to the higher solubility of water in the continuous phase consisting of octane (10% by weight) and 1-butanol. The penetration of a large amount of octane molecules between展开更多
Fast-charging lithium-ion batteries are highly required,especially in reducing the mileage anxiety of the widespread electric vehicles.One of the biggest bottlenecks lies in the sluggish kinetics of the Li^(+)intercal...Fast-charging lithium-ion batteries are highly required,especially in reducing the mileage anxiety of the widespread electric vehicles.One of the biggest bottlenecks lies in the sluggish kinetics of the Li^(+)intercalation into the graphite anode;slow intercalation will lead to lithium metal plating,severe side reactions,and safety concerns.The premise to solve these problems is to fully understand the reaction pathways and rate-determining steps of graphite during fast Li^(+)intercalation.Herein,we compare the Li^(+)diffusion through the graphite particle,interface,and electrode,uncover the structure of the lithiated graphite at high current densities,and correlate them with the reaction kinetics and electrochemical performances.It is found that the rate-determining steps are highly dependent on the particle size,interphase property,and electrode configuration.Insufficient Li^(+)diffusion leads to high polarization,incomplete intercalation,and the coexistence of several staging structures.Interfacial Li^(+)diffusion and electrode transportation are the main rate-determining steps if the particle size is less than 10μm.The former is highly dependent on the electrolyte chemistry and can be enhanced by constructing a fluorinated interphase.Our findings enrich the understanding of the graphite structural evolution during rapid Li^(+)intercalation,decipher the bottleneck for the sluggish reaction kinetics,and provide strategic guidelines to boost the fast-charging performance of graphite anode.展开更多
Energy materials are vital to energy conversion and storage devices that make renewable resources viable for electrification technologies. In situ transmission electron microscopy(TEM) is a powerful approach to charac...Energy materials are vital to energy conversion and storage devices that make renewable resources viable for electrification technologies. In situ transmission electron microscopy(TEM) is a powerful approach to characterize the dynamic evolution of material structure, morphology, and chemistry at the atomic scale in real time and in operando. In this review, recent advancements of in situ TEM techniques for studying energy materials, including catalysts, batteries, photovoltaics, and thermoelectrics, are systematically discussed and summarized. The topics include a broad range of material transformations that are in situ stimulated by heating, biasing, lighting, electron-beam illuminating, and cryocooling under vacuum, liquid, or gas environments within TEM, as well as the mechanistic understanding of the associated solid-solid, solid-liquid, and solid-gas reactions elucidated by in situ TEM examination and operando measurements. Special focus is also put on the emerging progress of artificial intelligence enabled microscopy data analytics, including machine learning enhanced tools for retrieving useful information from massive TEM imaging, diffraction, and spectroscopy datasets, highlighting its merits and potential for automated in situ TEM experimentation and analysis. Finally, the pressing challenges and future perspectives on in situ TEM study for energy-related materials are discussed.展开更多
Intercalation provides to the host materials a means for controlled variation of many physical/chemical properties and dominates the reactions in metal‐ion batteries.Of particular interest is the graphite intercalati...Intercalation provides to the host materials a means for controlled variation of many physical/chemical properties and dominates the reactions in metal‐ion batteries.Of particular interest is the graphite intercalation compounds with intriguing staging structures,which however are still unclear,especially in their nanostructure and dynamic transition mechanism.Herein,the nature of the staging structure and evolution of the lithium(Li)‐intercalated graphite was revealed by cryogenic‐transmission electron microscopy and other methods at the nanoscale.The intercalated Li‐ions distribute unevenly,generating local stress and dislocations in the graphitic structure.Each staging compound is found macroscopically ordered but microscopically inhomogeneous,exhibiting a localized‐domains structural model.Our findings uncover the correlation between the long‐range ordered structure and short‐range domains,refresh the insights on the staging structure and transition of Li‐intercalated/deintercalated graphite,and provide effective ways to enhance the reaction kinetic in rechargeable batteries by defect engineering.展开更多
Uniform lithium(Li)deposition in all-solid-state Li metal batteries is greatly influenced by the anode/electrolyte interface.Herein,a Mg-modified interface was constructed via the simple in-situ electrochemical reduct...Uniform lithium(Li)deposition in all-solid-state Li metal batteries is greatly influenced by the anode/electrolyte interface.Herein,a Mg-modified interface was constructed via the simple in-situ electrochemical reduction of Mg^(2+)from Mg(TFSI)_(2) in polyethylene oxide(PEO)and a Li bis(trifluoromethane)sulfoni mide(Li TFSI)formulae.As confirmed by cryogenic transmission electron microscopy,the anode/electrolyte interface exhibited hybrids consisting of crystalline Mg,Li_(2)O,and Li dots embedded in an amorphous polymer electrolyte.The crystalline Mg dots guided the uniform Li nucleation and growth,inducing a smoother anode/electrolyte interface compared with the pristine electrolyte.With 1 wt%Mg(TFSI)_(2) in the PEO-Li TFSI electrolyte,the Mg-modified electrolyte enabled the Li/Li symmetric cells with cycling performance of over 1700 and 1400 h at current densities of 0.1 and 0.2 m A cm^(-2),respectively.Moreover,the full LFP/Li cells using the novel Mg-modified electrolyte delivered a cycling lifespan of over 450 cycles with negligible capacity loss.展开更多
It is challenging for many drugs to be transported across various biological membranes. Furthermore, development of many drugs gets thwarted owing to their hydrophilic nature. The bioavailability of such drugs, which ...It is challenging for many drugs to be transported across various biological membranes. Furthermore, development of many drugs gets thwarted owing to their hydrophilic nature. The bioavailability of such drugs, which is the function of their ability to cross the membrane, tends to be low and exhibit high intra and inter subject variability. At present, formulation scientists are pursuing many projects for transdermal, nasal, target delivery of many active compounds, and it is prudent to explore alternative possibilities. Cubosomes offer transportation and tailoring of active compounds intended for both systemic and dermal delivery. Cubosomes are dispersed, self-assembled nanoparticles of bicontinuous cubic liquid crystalline phase formed from lipid and surfactant systems. Monoolein, poloxamer 407 and polyvinyl alcohol are the mostly used ingredients in the formulation of cubosomes. The adjustment in lipid composition can control the internal and structural changes of cubosomes. Based on the nodal surfaces, three structures of cubosomes proposed are Pn3m, Ia3d and Im3m. Top-down and bottom-up techniques are widely considered in the formulation process of extreme viscous bulk phase and aggregate from a precursor respectively. This article gives a bird's eye view about the engineering, characterization and evaluation of cubosomes, covering researches and applications of cubosomes done till date.展开更多
Li-ion batteries(LIBs)have dominated energy-storage techniques for portable electronic devices and electric cars,and are expanding their territory into the large-scale energy storage.The energy storage of LIBs is real...Li-ion batteries(LIBs)have dominated energy-storage techniques for portable electronic devices and electric cars,and are expanding their territory into the large-scale energy storage.The energy storage of LIBs is realized by the reversible shuttle of lithium ions between electrodes.It is essential to track the lithium diffusion and obtain a profound insight into the lithiation mechanism during the work cycle of LIBs.Transmission electron microscopy(TEM)is a powerful tool for the structural characterization,which can provide the information about the lithiation at the atomic scale.In this review,we summarize the research frontiers of TEM applications on LIBs.We introduce the techniques for the direct observation of Li species in LIB-related materials.Especially,the application of cryo-TEM is highlighted.Moreover,in-situ TEM technique is further discussed since it shows great advantages in studying the dynamical structure changes of LIBs.The perspectives and strategies in this review offer feasible guidance for researchers to further improve the performance of LIBs.展开更多
The fast development of electron microscopy has enabled unprecedented achievements in the field of life science and materials science[1–6].In particular,the 2017 Nobel Prize of chemistry was awarded to three scientis...The fast development of electron microscopy has enabled unprecedented achievements in the field of life science and materials science[1–6].In particular,the 2017 Nobel Prize of chemistry was awarded to three scientists who contributed significantly to developing cryo-electron microscopy(Cryo-EM)[7].This technique,involving fast freezing the biological samples using liquid nitrogen,was originally designed to keep"live cells"intact from water evaporation and crystallization and immune to展开更多
基金This work was supported by the National Natural Science Foundation of China (Grant No. 29903006) and the Visiting Scholar Foundation for Key Laboratories in Universities of China.
文摘In this work, the effect of octane concentration on the phase behavior of CTAB/water/1-butanol system was studied by using pulsed field gradient spin-echo NMR measurements and freeze fracture electron microscopy (Cryo-TEM and FFEM). When the octane concentration increases, the liquid crystalline phase is destabilized and a continuous single-phase microemulsion region from the water apex to the oil apex is formed. The conductivity behavior has a distinct percolative phenomenon, which indicates that the single-phase microemulsion is changed continuously from oil-in-water (o/w) structure via a bicontinuous structure to wa-ter-in-oil (w/o) structure. This result is consistent with those of the PGSE-NMR, Cryo-TEM, and FFEM. In the w/o region, the self-diffusion coefficient of water is relatively high ((1-6) ×1(T-10 m . s-1) due to the higher solubility of water in the continuous phase consisting of octane (10% by weight) and 1-butanol. The penetration of a large amount of octane molecules between
基金supported by the National Natural Science Foundation of China(NSFC No.52172257 and 22005334)the Natural Science Foundation of Beijing(Grant No.Z200013)the National Key Research and Development Program of China(Grant No.2022YFB2502200).
文摘Fast-charging lithium-ion batteries are highly required,especially in reducing the mileage anxiety of the widespread electric vehicles.One of the biggest bottlenecks lies in the sluggish kinetics of the Li^(+)intercalation into the graphite anode;slow intercalation will lead to lithium metal plating,severe side reactions,and safety concerns.The premise to solve these problems is to fully understand the reaction pathways and rate-determining steps of graphite during fast Li^(+)intercalation.Herein,we compare the Li^(+)diffusion through the graphite particle,interface,and electrode,uncover the structure of the lithiated graphite at high current densities,and correlate them with the reaction kinetics and electrochemical performances.It is found that the rate-determining steps are highly dependent on the particle size,interphase property,and electrode configuration.Insufficient Li^(+)diffusion leads to high polarization,incomplete intercalation,and the coexistence of several staging structures.Interfacial Li^(+)diffusion and electrode transportation are the main rate-determining steps if the particle size is less than 10μm.The former is highly dependent on the electrolyte chemistry and can be enhanced by constructing a fluorinated interphase.Our findings enrich the understanding of the graphite structural evolution during rapid Li^(+)intercalation,decipher the bottleneck for the sluggish reaction kinetics,and provide strategic guidelines to boost the fast-charging performance of graphite anode.
基金supported in part by the American Chemical Society Petroleum Research Fund (No. 62493-NDI10)support of Hitachi High-Technologies Electron Microscopy Fellowship。
文摘Energy materials are vital to energy conversion and storage devices that make renewable resources viable for electrification technologies. In situ transmission electron microscopy(TEM) is a powerful approach to characterize the dynamic evolution of material structure, morphology, and chemistry at the atomic scale in real time and in operando. In this review, recent advancements of in situ TEM techniques for studying energy materials, including catalysts, batteries, photovoltaics, and thermoelectrics, are systematically discussed and summarized. The topics include a broad range of material transformations that are in situ stimulated by heating, biasing, lighting, electron-beam illuminating, and cryocooling under vacuum, liquid, or gas environments within TEM, as well as the mechanistic understanding of the associated solid-solid, solid-liquid, and solid-gas reactions elucidated by in situ TEM examination and operando measurements. Special focus is also put on the emerging progress of artificial intelligence enabled microscopy data analytics, including machine learning enhanced tools for retrieving useful information from massive TEM imaging, diffraction, and spectroscopy datasets, highlighting its merits and potential for automated in situ TEM experimentation and analysis. Finally, the pressing challenges and future perspectives on in situ TEM study for energy-related materials are discussed.
基金support from the National Natural Science Foundation of China(NSFC nos.52172257,22005334,21773301 and 52022106)the Natural Science Foundation of Beijing(grant no.Z200013).
文摘Intercalation provides to the host materials a means for controlled variation of many physical/chemical properties and dominates the reactions in metal‐ion batteries.Of particular interest is the graphite intercalation compounds with intriguing staging structures,which however are still unclear,especially in their nanostructure and dynamic transition mechanism.Herein,the nature of the staging structure and evolution of the lithium(Li)‐intercalated graphite was revealed by cryogenic‐transmission electron microscopy and other methods at the nanoscale.The intercalated Li‐ions distribute unevenly,generating local stress and dislocations in the graphitic structure.Each staging compound is found macroscopically ordered but microscopically inhomogeneous,exhibiting a localized‐domains structural model.Our findings uncover the correlation between the long‐range ordered structure and short‐range domains,refresh the insights on the staging structure and transition of Li‐intercalated/deintercalated graphite,and provide effective ways to enhance the reaction kinetic in rechargeable batteries by defect engineering.
基金financial support from the National Natural Science Foundation of China(Grant no.51722210,51972285,U1802254,11904317,and 21902144)the Natural Science Foundation of Zhejiang Province(Grant no.LY17E020010 and LD18E020003)the Innovation Fund of the Zhejiang Kechuang New Materials Research Institute(Grant no.ZKN-18P05)。
文摘Uniform lithium(Li)deposition in all-solid-state Li metal batteries is greatly influenced by the anode/electrolyte interface.Herein,a Mg-modified interface was constructed via the simple in-situ electrochemical reduction of Mg^(2+)from Mg(TFSI)_(2) in polyethylene oxide(PEO)and a Li bis(trifluoromethane)sulfoni mide(Li TFSI)formulae.As confirmed by cryogenic transmission electron microscopy,the anode/electrolyte interface exhibited hybrids consisting of crystalline Mg,Li_(2)O,and Li dots embedded in an amorphous polymer electrolyte.The crystalline Mg dots guided the uniform Li nucleation and growth,inducing a smoother anode/electrolyte interface compared with the pristine electrolyte.With 1 wt%Mg(TFSI)_(2) in the PEO-Li TFSI electrolyte,the Mg-modified electrolyte enabled the Li/Li symmetric cells with cycling performance of over 1700 and 1400 h at current densities of 0.1 and 0.2 m A cm^(-2),respectively.Moreover,the full LFP/Li cells using the novel Mg-modified electrolyte delivered a cycling lifespan of over 450 cycles with negligible capacity loss.
文摘It is challenging for many drugs to be transported across various biological membranes. Furthermore, development of many drugs gets thwarted owing to their hydrophilic nature. The bioavailability of such drugs, which is the function of their ability to cross the membrane, tends to be low and exhibit high intra and inter subject variability. At present, formulation scientists are pursuing many projects for transdermal, nasal, target delivery of many active compounds, and it is prudent to explore alternative possibilities. Cubosomes offer transportation and tailoring of active compounds intended for both systemic and dermal delivery. Cubosomes are dispersed, self-assembled nanoparticles of bicontinuous cubic liquid crystalline phase formed from lipid and surfactant systems. Monoolein, poloxamer 407 and polyvinyl alcohol are the mostly used ingredients in the formulation of cubosomes. The adjustment in lipid composition can control the internal and structural changes of cubosomes. Based on the nodal surfaces, three structures of cubosomes proposed are Pn3m, Ia3d and Im3m. Top-down and bottom-up techniques are widely considered in the formulation process of extreme viscous bulk phase and aggregate from a precursor respectively. This article gives a bird's eye view about the engineering, characterization and evaluation of cubosomes, covering researches and applications of cubosomes done till date.
基金supported by the National Key R&D Program of China(2020YFB2007400)the National Natural Science Foundation of China(22075317)the Strategic Priority Research Program(B)(XDB07030200)of Chinese Academy of Sciences。
文摘Li-ion batteries(LIBs)have dominated energy-storage techniques for portable electronic devices and electric cars,and are expanding their territory into the large-scale energy storage.The energy storage of LIBs is realized by the reversible shuttle of lithium ions between electrodes.It is essential to track the lithium diffusion and obtain a profound insight into the lithiation mechanism during the work cycle of LIBs.Transmission electron microscopy(TEM)is a powerful tool for the structural characterization,which can provide the information about the lithiation at the atomic scale.In this review,we summarize the research frontiers of TEM applications on LIBs.We introduce the techniques for the direct observation of Li species in LIB-related materials.Especially,the application of cryo-TEM is highlighted.Moreover,in-situ TEM technique is further discussed since it shows great advantages in studying the dynamical structure changes of LIBs.The perspectives and strategies in this review offer feasible guidance for researchers to further improve the performance of LIBs.
文摘The fast development of electron microscopy has enabled unprecedented achievements in the field of life science and materials science[1–6].In particular,the 2017 Nobel Prize of chemistry was awarded to three scientists who contributed significantly to developing cryo-electron microscopy(Cryo-EM)[7].This technique,involving fast freezing the biological samples using liquid nitrogen,was originally designed to keep"live cells"intact from water evaporation and crystallization and immune to
