Increasing the charging cut-off potential of lithium cobalt oxide(LiCoO_(2),LCO)can effectively improve the energy density of the lithium-ion batteries,which are the mainstream energy storage devices used in 3C electr...Increasing the charging cut-off potential of lithium cobalt oxide(LiCoO_(2),LCO)can effectively improve the energy density of the lithium-ion batteries,which are the mainstream energy storage devices used in 3C electronic products.However,the continuous decomposition of the electrolyte and dissolution of Co from the electrode will occur at high-potential operation,which deteriorate the performances of LCO.Here,a cathode-electrolyte interface(CEI)layer containing Mg F_(2)is constructed to enhance the electrochemical stability of LCO at 4.6 V(vs.Li^(+)/Li).The Mg^(2+)added to the cathode gradually releases into the electrolyte during cycling,which forms a stable Mg F_(2)-rich protective layer.In addition,1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropylether(TTE)is added to the electrolyte acting as a F source to increase the content of Mg F_(2)in the CEI layer.The Mg F_(2)-rich CEI layer effectively suppresses the decomposition of electrolyte components and the dissolution of Co of LCO,which makes the Li||LiCoO_(2)(Li||LCO)cell cycled stably at 3~4.6 V(vs.Li^(+)/Li)in 200 cycles with a retention of 83.9%.展开更多
Commercial carbonate electrolytes suffer from ion transport difficulty in bulk electrolytes and interphase at low temperatures,bringing challenges to the application of lithium-ion batteries(LIBs)at low temperatures.H...Commercial carbonate electrolytes suffer from ion transport difficulty in bulk electrolytes and interphase at low temperatures,bringing challenges to the application of lithium-ion batteries(LIBs)at low temperatures.Herein,the ester solvent of methyl propionate(MP)with low melting point and low viscosity was used to tackle ion transport difficulty in electrolytes.Fluorinated ester was further added to accelerate interfacial transport through intermolecular interactions.The influence of fluorinated esters with different fluorination degrees on the solvation structure of electrolytes and the performance of batteries was further studied.As a result,methyl pentafluoropropionate(M5F)with five fluorine atoms was selected for its optimal interactions with both Li+and MP solvent in the primary solvation structure,contributing to desired solvation structure for fast interfacial transport.The LiFePO4(LFP)||graphite cell with LiFSI-MP-M5F electrolyte exhibited a high cyclability of 85.8%after 120 cycles and retained 81.2%of room-temperature capacity when charged and discharged at−30℃.1 Ah LFP||graphite pouch cell with high cathode loading(20 mg/cm^(2))in LiFSI-MP-M5F electrolyte exhibited 0.85 Ah capacity when charged and discharged at−20℃.This work provides a guidance for electrolyte design by synergistic fluorinated and non-fluorinated solvents for LIBs at low-temperature application.展开更多
2-Substituted-2,3-dihydro-4(1H)-quinazolinones were obtained in high yields by condensation of anthranilamide with aryl, alkyl or heteroaryl aldehydes or ketones in the refluxing 2,2,2-trifluoroethanol without any cat...2-Substituted-2,3-dihydro-4(1H)-quinazolinones were obtained in high yields by condensation of anthranilamide with aryl, alkyl or heteroaryl aldehydes or ketones in the refluxing 2,2,2-trifluoroethanol without any catalyst.展开更多
The one-pot aza-Diels-Alder reaction of substituted aromatic amines, ethyl glyoxylate and benzyl vinylcarbamate or N- benzyloxycarbonyl 2-pyrroline was conducted in hexafluoroisopropanol, providing the desired 1,2,3,4...The one-pot aza-Diels-Alder reaction of substituted aromatic amines, ethyl glyoxylate and benzyl vinylcarbamate or N- benzyloxycarbonyl 2-pyrroline was conducted in hexafluoroisopropanol, providing the desired 1,2,3,4-tetrahydroquinline derivatives in moderate yields.展开更多
基金supported by National Natural Science Foundation of China(Nos.22075172 and 22075170)the Opening Project of Key Laboratory of Optoelectronic Chemical Materials and Devices of Ministry of Education,Jianghan University(No.JDGD202221)。
文摘Increasing the charging cut-off potential of lithium cobalt oxide(LiCoO_(2),LCO)can effectively improve the energy density of the lithium-ion batteries,which are the mainstream energy storage devices used in 3C electronic products.However,the continuous decomposition of the electrolyte and dissolution of Co from the electrode will occur at high-potential operation,which deteriorate the performances of LCO.Here,a cathode-electrolyte interface(CEI)layer containing Mg F_(2)is constructed to enhance the electrochemical stability of LCO at 4.6 V(vs.Li^(+)/Li).The Mg^(2+)added to the cathode gradually releases into the electrolyte during cycling,which forms a stable Mg F_(2)-rich protective layer.In addition,1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropylether(TTE)is added to the electrolyte acting as a F source to increase the content of Mg F_(2)in the CEI layer.The Mg F_(2)-rich CEI layer effectively suppresses the decomposition of electrolyte components and the dissolution of Co of LCO,which makes the Li||LiCoO_(2)(Li||LCO)cell cycled stably at 3~4.6 V(vs.Li^(+)/Li)in 200 cycles with a retention of 83.9%.
基金supported by the National Key R&D Program of China(No.2022YFB3803400)National Natural Science Foundation of China(Nos.52102054,52020105010,51927803,52188101 and 52072378)+1 种基金Liaoning Province Science and Technology Planning Project(No.2022-BS-007)Fujian Science and Technology Program(No.2023T3025).
文摘Commercial carbonate electrolytes suffer from ion transport difficulty in bulk electrolytes and interphase at low temperatures,bringing challenges to the application of lithium-ion batteries(LIBs)at low temperatures.Herein,the ester solvent of methyl propionate(MP)with low melting point and low viscosity was used to tackle ion transport difficulty in electrolytes.Fluorinated ester was further added to accelerate interfacial transport through intermolecular interactions.The influence of fluorinated esters with different fluorination degrees on the solvation structure of electrolytes and the performance of batteries was further studied.As a result,methyl pentafluoropropionate(M5F)with five fluorine atoms was selected for its optimal interactions with both Li+and MP solvent in the primary solvation structure,contributing to desired solvation structure for fast interfacial transport.The LiFePO4(LFP)||graphite cell with LiFSI-MP-M5F electrolyte exhibited a high cyclability of 85.8%after 120 cycles and retained 81.2%of room-temperature capacity when charged and discharged at−30℃.1 Ah LFP||graphite pouch cell with high cathode loading(20 mg/cm^(2))in LiFSI-MP-M5F electrolyte exhibited 0.85 Ah capacity when charged and discharged at−20℃.This work provides a guidance for electrolyte design by synergistic fluorinated and non-fluorinated solvents for LIBs at low-temperature application.
文摘2-Substituted-2,3-dihydro-4(1H)-quinazolinones were obtained in high yields by condensation of anthranilamide with aryl, alkyl or heteroaryl aldehydes or ketones in the refluxing 2,2,2-trifluoroethanol without any catalyst.
基金the National Natural Science Foundation of China(No.30672540)NSF of Beijing(No.7072048)for financial support.
文摘The one-pot aza-Diels-Alder reaction of substituted aromatic amines, ethyl glyoxylate and benzyl vinylcarbamate or N- benzyloxycarbonyl 2-pyrroline was conducted in hexafluoroisopropanol, providing the desired 1,2,3,4-tetrahydroquinline derivatives in moderate yields.
