Metal skeletons,such as Nickel Foam(NF) has attracted worldwide interests as stable host for lithium metal anode because of its high stability,large specific surface area and high conductivity.However,most metal skele...Metal skeletons,such as Nickel Foam(NF) has attracted worldwide interests as stable host for lithium metal anode because of its high stability,large specific surface area and high conductivity.However,most metal skeletons have lithophobic surface and uneven current distribution that result in sporadic lithium nucleation and uncontrolled dendrites growth.Herein,we describe a sequential immersing strategy to generate interwoven Nickel(Ⅱ)-dimethylglyoxime(Ni-DMG) nanowires at NF to obtain composite skeleton(NDNF),which can be used as an stable host for Li metal storage.The Ni-DMG has proved effective to realize uniform lithium nucleation and dendrite-free lithium deposition.Combing with the three dimensional(3 D) hierarchical porous structure,the composite host shows a significantly improved coulombic efficiency(CE) than pristine commercial nickel foam.Moreover,the corresponding Li‖Li symmetrical cells can run more than 700 h with low voltage hysteresis 22 mV at 1.0 mA/cm^(2),and Li@NDNF‖LiFePO;full-cell exhibits a high capacity retention of 82.03% at 1.0 C during 630 cycles.These results proved the effectiveness of metal-organic complexes in governing Li metal growth and can be employed as a new strategy for dendrite-free Li metal anode and safe Li metal batteries(LMBs).展开更多
Photonic crystals are periodic structural materials that have an impact on the propagation properties of photons.Due to their excellent optical,electrical and magnetic properties,their advantages and potential for app...Photonic crystals are periodic structural materials that have an impact on the propagation properties of photons.Due to their excellent optical,electrical and magnetic properties,their advantages and potential for applications in the above areas are gradually emerging.Therefore,an increasing number of researchers have focused on photonic crystals.In this paper,the characteristics of biological photonic crystal structures,such as those found in butterfly wings,sea mouse bristles,peacock feathers,melon jellyfish epidermal cells,and weevil exoskeletons,are described.The preparation methods of photonic crystals are systematically summarized(including the template method,self-assembly technology,electron beam evaporation coating technology,chemical vapor deposition technology,femtosecond laser two-photon technology,spin coating technology,and a variety of technology mixing),and the characteristics,advantages,and disadvantages of the different methods are compared.Furthermore,the development of photonic crystals in the field of sensors,solar cells,filters,and infrared stealth is discussed,demonstrateing the great development potential of photonic crystals.It is concluded that the realization of photonic crystals with high precision,high sensitivity,angle independence,and large-area uniform preparation is a key problem requiring urgent solution.Moreover,photonic crystals have potential development prospects in the fields of equipment stealth,new concept weapons,production,an daily life.展开更多
The effect of cosolvent on the palladium catalyst which catalyze alkoxycarbonylation of allyl bromide in supercritical CO2 has been investigated. It was found that a small amount of cosolvent such as ethanol, CH2Cl2 a...The effect of cosolvent on the palladium catalyst which catalyze alkoxycarbonylation of allyl bromide in supercritical CO2 has been investigated. It was found that a small amount of cosolvent such as ethanol, CH2Cl2 and cyclohexane can affect both reaction yields and selectivities largely. Ethanol was the most favorable cosolvent for increasing the total yield of unsaturated esters and the selectivity of 3-butenoic acid ester. Using cosolvent ethanol and cocatalyst FeCl2 Simultaneously can lead to better reaction results.展开更多
基金financially supported by PULEAD Technology Industry Co.,Ltd.,the Strategic Priority Research Program of Chinese Academy of Sciences (No. XDB36000000)the National Key Research and Development Program of China (No. 2016YFA0200904)+3 种基金the National Natural Science Foundation of China (Nos. 21771018and 21875004)the Natural Science Foundation of Beijing (No.2192018)National Natural Science Foundation of China-Regional Innovation Joint Exploration Fund (No. U19A2019)Beijing University of Chemical Technology (Start-up grant No. buctrc201901,BUCT, China)。
文摘Metal skeletons,such as Nickel Foam(NF) has attracted worldwide interests as stable host for lithium metal anode because of its high stability,large specific surface area and high conductivity.However,most metal skeletons have lithophobic surface and uneven current distribution that result in sporadic lithium nucleation and uncontrolled dendrites growth.Herein,we describe a sequential immersing strategy to generate interwoven Nickel(Ⅱ)-dimethylglyoxime(Ni-DMG) nanowires at NF to obtain composite skeleton(NDNF),which can be used as an stable host for Li metal storage.The Ni-DMG has proved effective to realize uniform lithium nucleation and dendrite-free lithium deposition.Combing with the three dimensional(3 D) hierarchical porous structure,the composite host shows a significantly improved coulombic efficiency(CE) than pristine commercial nickel foam.Moreover,the corresponding Li‖Li symmetrical cells can run more than 700 h with low voltage hysteresis 22 mV at 1.0 mA/cm^(2),and Li@NDNF‖LiFePO;full-cell exhibits a high capacity retention of 82.03% at 1.0 C during 630 cycles.These results proved the effectiveness of metal-organic complexes in governing Li metal growth and can be employed as a new strategy for dendrite-free Li metal anode and safe Li metal batteries(LMBs).
基金Supported by National Natural Science Foundation of China(Grant Nos.52275227,52130509)Key Basic Research Project of the Foundation Strengthening Plan of China(Grant Nos.2019-JCJQ-JJ-034,2019-JCJQ-ZD-302).
文摘Photonic crystals are periodic structural materials that have an impact on the propagation properties of photons.Due to their excellent optical,electrical and magnetic properties,their advantages and potential for applications in the above areas are gradually emerging.Therefore,an increasing number of researchers have focused on photonic crystals.In this paper,the characteristics of biological photonic crystal structures,such as those found in butterfly wings,sea mouse bristles,peacock feathers,melon jellyfish epidermal cells,and weevil exoskeletons,are described.The preparation methods of photonic crystals are systematically summarized(including the template method,self-assembly technology,electron beam evaporation coating technology,chemical vapor deposition technology,femtosecond laser two-photon technology,spin coating technology,and a variety of technology mixing),and the characteristics,advantages,and disadvantages of the different methods are compared.Furthermore,the development of photonic crystals in the field of sensors,solar cells,filters,and infrared stealth is discussed,demonstrateing the great development potential of photonic crystals.It is concluded that the realization of photonic crystals with high precision,high sensitivity,angle independence,and large-area uniform preparation is a key problem requiring urgent solution.Moreover,photonic crystals have potential development prospects in the fields of equipment stealth,new concept weapons,production,an daily life.
文摘The effect of cosolvent on the palladium catalyst which catalyze alkoxycarbonylation of allyl bromide in supercritical CO2 has been investigated. It was found that a small amount of cosolvent such as ethanol, CH2Cl2 and cyclohexane can affect both reaction yields and selectivities largely. Ethanol was the most favorable cosolvent for increasing the total yield of unsaturated esters and the selectivity of 3-butenoic acid ester. Using cosolvent ethanol and cocatalyst FeCl2 Simultaneously can lead to better reaction results.
