Rechargeable battery cycling performance and related safety have been persistent concerns.It is crucial to decipher the capacity fading induced by electrode material failure via a range of techniques.Among these,synch...Rechargeable battery cycling performance and related safety have been persistent concerns.It is crucial to decipher the capacity fading induced by electrode material failure via a range of techniques.Among these,synchrotron-based X-ray techniques with high flux and brightness play a key role in understanding degradation mechanisms.In this comprehensive review,we summarize recent advancements in degra-dation modes and mechanisms that were revealed by synchrotron X-ray methodologies.Subsequently,an overview of X-ray absorption spectroscopy and X-ray scattering techniques is introduced for charac-terizing failure phenomena at local coordination atomic environment and long-range order crystal struc-ture scale,respectively.At last,we envision the future of exploring material failure mechanism.展开更多
Nanostructured transition metal oxides,employed as anode materials for lithium-ion batteries,exhibit a higher capacity than the theoretical capacity based on the conversion reaction.To date,the reasons behind this phe...Nanostructured transition metal oxides,employed as anode materials for lithium-ion batteries,exhibit a higher capacity than the theoretical capacity based on the conversion reaction.To date,the reasons behind this phenomenon are unclear.For the one-step evolution of anode material for lithium-ion batteries,it is essential to understand the lithium storage reaction mechanism of the anode material.Herein,we provide a detailed report on the lithium storage and release mechanism of MnO2,using synchrotron-based X-ray techniques.X-ray diffraction and X-ray absorption spectroscopy results indicate that during the first discharge,MnO2 is reduced in the order of MnO2→LixMnO2(1<X<2)→MnO→Mn metal,followed by a reversible reaction between Mn metal and Mn3O4.Furthermore,soft X-ray absorption spectroscopy results indicate that additional reversible formation-decomposition of the electrolyte-derived surface layer occurs and contributes to the reversible capacity of MnO2 after the first discharge.These findings contribute to further understanding of the reaction mechanism and additional lithium storage of MnO2 and suggest practical strategies for developing high energy density anode materials for next-generation Li batteries.展开更多
All-solid-state batteries offer an attractive option for developing safe lithium-ion batteries.Among the various solid-state electrolyte candidates for their applications,sulfide solid electrolytes are the most suitab...All-solid-state batteries offer an attractive option for developing safe lithium-ion batteries.Among the various solid-state electrolyte candidates for their applications,sulfide solid electrolytes are the most suitable owing to their high ionic conductivity and facile processability.However,their performance is extensively lower compared with those of conventional liquid electrolyte-based batteries mainly because of interfacial reactions between the solid electrolytes and high capacity cathodes.Moreover,the kinetic evolution reaction in the composite cathode of all-solid-state lithium batteries has not been actively discussed.Here,electrochemical analyses were performed to investigate the differences between the organic liquid electrolyte-based battery and all-solid-state battery systems.Combined with electrochemical analyses and synchrotron-based in situ and ex situ X-ray analyses,it was confirmed that inhomogeneous reactions were due to physical contact.Loosely contacted and/or isolated active material particles account for the inhomogeneously charged regions,which further intensify the inhomogeneous reactions during extended cycles,thereby increasing the polarization of the system.This study highlighted the benefits of electrochemo-mechanical integrity for securing a smooth conduction pathway and the development of a reliable homogeneous reaction system for the success of solid-state batteries.展开更多
Recent success and application of the percolation theory have highlighted cation-disordered Li-rich oxides as high energy density cathode materials. Generally, this kind of cathode materials suffer from low cycling st...Recent success and application of the percolation theory have highlighted cation-disordered Li-rich oxides as high energy density cathode materials. Generally, this kind of cathode materials suffer from low cycling stability and rate performance. Doped Ti4^+ ions can improve the long-term cycling stability and rate performance of the Li-rich oxides materials with obvious capacity fading. The electrochemical performance in LixNi2-4x/3Sbx/3O2 can benefit a lot from the nanohighway, which is a kind of nanoscale 0-TM diffusion channels in the transition metal layer and provides low diffusion barrier pathways for the lithium diffusion. In this work, the doping effect of Ti on the structure and electrochemical properties in Li1.15Ni0.47Sb0.38O2 is studied. The Ti-stabilized Li1.15-xNi0.47TixSb0.38O2 (x=0, 0.01, 0.03 and 0.05) have been prepared by a solid-state method and the Li1.03Ni0.47Sb0.38Ti0.03O2 sample exhibits outstanding electrochemical performance with a larger reversible discharge capacity, better rate capability and cyclability. Synchrotron-based XANES, combined with ab initio calculations in the multiple-scattering flame- work, reveals the Ti ions have been doped into the Li-site in the lithium layer and formed a distortion TiO6 octahedron. This TiO6 local configuration in the lithium can keep the stability of nanohighway in the electrochemical pro- cess. In particular, the Lil.03Ni0.47Sb0.38Ti0.03O2 compound can deliver a discharge capacities 132 and 76 mAh/g at 0.2 and 5 C, respectivly. About 86% capacity retention occurs at 1 C rate after 500 cycles. This work suggests capacity fading in the oxide cathode materials can be suppressed to construct and stabilize the nanohighway.展开更多
Polycyclic aromatic hydrocarbons(PAHs)are persistent and widespread in the aquatic environment,causing potential hazards for human health.In this study,a superwetting and robust PES-PAA-ZrO_(2)nanofiltration membrane ...Polycyclic aromatic hydrocarbons(PAHs)are persistent and widespread in the aquatic environment,causing potential hazards for human health.In this study,a superwetting and robust PES-PAA-ZrO_(2)nanofiltration membrane was proposed through surface modification for PAH removal with high efficiency.A ZrO_(2)coating was formed on polyethersulfone(PES)membrane surface through chemical bonding,thus the PES-PAA-ZrO_(2)membrane exhibited super-hydrophilicity,under-water oleophobicity,and excellent stability.In comparison with the original PES membrane,the water contact angle of the modified membrane was significantly decreased from about 50°to less than 10°,and quickly dropped to 0°within 1s.This provided a much lower energy barrier for water permeation due to its super-high water affinity.The wastewater treatment efficiency was increased by about 4 times after modification with more than 90%of PAH rejection rate.The excellent robustness of PES-PAA-ZrO_(2)membrane was verified under various conditions,which gave the membrane practical potential for long-term operation.展开更多
基金supported by the U.S.National Science Foundation (2208972,2120559,and 2323117)
文摘Rechargeable battery cycling performance and related safety have been persistent concerns.It is crucial to decipher the capacity fading induced by electrode material failure via a range of techniques.Among these,synchrotron-based X-ray techniques with high flux and brightness play a key role in understanding degradation mechanisms.In this comprehensive review,we summarize recent advancements in degra-dation modes and mechanisms that were revealed by synchrotron X-ray methodologies.Subsequently,an overview of X-ray absorption spectroscopy and X-ray scattering techniques is introduced for charac-terizing failure phenomena at local coordination atomic environment and long-range order crystal struc-ture scale,respectively.At last,we envision the future of exploring material failure mechanism.
基金supported by the Samsung Reserach Funding & Incubation Center of Samsung Electronics under Project Number MA1401-52。
文摘Nanostructured transition metal oxides,employed as anode materials for lithium-ion batteries,exhibit a higher capacity than the theoretical capacity based on the conversion reaction.To date,the reasons behind this phenomenon are unclear.For the one-step evolution of anode material for lithium-ion batteries,it is essential to understand the lithium storage reaction mechanism of the anode material.Herein,we provide a detailed report on the lithium storage and release mechanism of MnO2,using synchrotron-based X-ray techniques.X-ray diffraction and X-ray absorption spectroscopy results indicate that during the first discharge,MnO2 is reduced in the order of MnO2→LixMnO2(1<X<2)→MnO→Mn metal,followed by a reversible reaction between Mn metal and Mn3O4.Furthermore,soft X-ray absorption spectroscopy results indicate that additional reversible formation-decomposition of the electrolyte-derived surface layer occurs and contributes to the reversible capacity of MnO2 after the first discharge.These findings contribute to further understanding of the reaction mechanism and additional lithium storage of MnO2 and suggest practical strategies for developing high energy density anode materials for next-generation Li batteries.
基金supported by the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIT)(No.NRF-2021M3H4A1A02045953 and No.NRF-2021R1C1C2007797)。
文摘All-solid-state batteries offer an attractive option for developing safe lithium-ion batteries.Among the various solid-state electrolyte candidates for their applications,sulfide solid electrolytes are the most suitable owing to their high ionic conductivity and facile processability.However,their performance is extensively lower compared with those of conventional liquid electrolyte-based batteries mainly because of interfacial reactions between the solid electrolytes and high capacity cathodes.Moreover,the kinetic evolution reaction in the composite cathode of all-solid-state lithium batteries has not been actively discussed.Here,electrochemical analyses were performed to investigate the differences between the organic liquid electrolyte-based battery and all-solid-state battery systems.Combined with electrochemical analyses and synchrotron-based in situ and ex situ X-ray analyses,it was confirmed that inhomogeneous reactions were due to physical contact.Loosely contacted and/or isolated active material particles account for the inhomogeneously charged regions,which further intensify the inhomogeneous reactions during extended cycles,thereby increasing the polarization of the system.This study highlighted the benefits of electrochemo-mechanical integrity for securing a smooth conduction pathway and the development of a reliable homogeneous reaction system for the success of solid-state batteries.
基金Supporting information for this article is available on the WWW under http://dx.doi.org/10. 1002/cjoc.201700265 or from the author.Acknowledgement This work was partly supported by the Science Fund for Creative Re search Groups of NSF C (No. 11321503), the National Key Research and Development Program of China (No. 2016YFA0401004), the National Natural Science Foundation of China (NSFC No. 11275227, U1632103), and the Youth Innovation Promotion Association CAS (No. 2014927).
文摘Recent success and application of the percolation theory have highlighted cation-disordered Li-rich oxides as high energy density cathode materials. Generally, this kind of cathode materials suffer from low cycling stability and rate performance. Doped Ti4^+ ions can improve the long-term cycling stability and rate performance of the Li-rich oxides materials with obvious capacity fading. The electrochemical performance in LixNi2-4x/3Sbx/3O2 can benefit a lot from the nanohighway, which is a kind of nanoscale 0-TM diffusion channels in the transition metal layer and provides low diffusion barrier pathways for the lithium diffusion. In this work, the doping effect of Ti on the structure and electrochemical properties in Li1.15Ni0.47Sb0.38O2 is studied. The Ti-stabilized Li1.15-xNi0.47TixSb0.38O2 (x=0, 0.01, 0.03 and 0.05) have been prepared by a solid-state method and the Li1.03Ni0.47Sb0.38Ti0.03O2 sample exhibits outstanding electrochemical performance with a larger reversible discharge capacity, better rate capability and cyclability. Synchrotron-based XANES, combined with ab initio calculations in the multiple-scattering flame- work, reveals the Ti ions have been doped into the Li-site in the lithium layer and formed a distortion TiO6 octahedron. This TiO6 local configuration in the lithium can keep the stability of nanohighway in the electrochemical pro- cess. In particular, the Lil.03Ni0.47Sb0.38Ti0.03O2 compound can deliver a discharge capacities 132 and 76 mAh/g at 0.2 and 5 C, respectivly. About 86% capacity retention occurs at 1 C rate after 500 cycles. This work suggests capacity fading in the oxide cathode materials can be suppressed to construct and stabilize the nanohighway.
基金supported by the National Key Research and Development Plan(2016YFA0601502)the Canada Research Chairs(CRC)Program+3 种基金the Canada Foundation for Innovation(CFI)the Natural Science and Engineering Research Council(NSERC)of CanadaWestern Canada Clean Energy Initiative(No.000015269)Petroleum Technology Research Centre
文摘Polycyclic aromatic hydrocarbons(PAHs)are persistent and widespread in the aquatic environment,causing potential hazards for human health.In this study,a superwetting and robust PES-PAA-ZrO_(2)nanofiltration membrane was proposed through surface modification for PAH removal with high efficiency.A ZrO_(2)coating was formed on polyethersulfone(PES)membrane surface through chemical bonding,thus the PES-PAA-ZrO_(2)membrane exhibited super-hydrophilicity,under-water oleophobicity,and excellent stability.In comparison with the original PES membrane,the water contact angle of the modified membrane was significantly decreased from about 50°to less than 10°,and quickly dropped to 0°within 1s.This provided a much lower energy barrier for water permeation due to its super-high water affinity.The wastewater treatment efficiency was increased by about 4 times after modification with more than 90%of PAH rejection rate.The excellent robustness of PES-PAA-ZrO_(2)membrane was verified under various conditions,which gave the membrane practical potential for long-term operation.