Photodissociation of H2S in the VUV region plays an important role in the atmospheric chemistry and interstellar chemistry.To date,however,few studies have been focused on this topic.In this article,we have described ...Photodissociation of H2S in the VUV region plays an important role in the atmospheric chemistry and interstellar chemistry.To date,however,few studies have been focused on this topic.In this article,we have described a laser dispersion method applied in the apparatus combining the high-n H atom Rydberg tagging time-of-flight technique with the vacuum ultraviolet free electron laser(VUV FEL).The Lyman-αlaser beam(121.6 nm)used in the H-atom detection was generated by the difference frequency four-wave mixing schemes in a Kr/Ar gas cell.After passing through an off-axis biconvex LiF lens,the 121.6 nm beam was dispersed from the 212.6 nm and 845 nm beams due to the different deflection angles experienced by these laser beams at the surfaces of the biconvex lens.This method can eliminate the background signal from the 212.6 nm photolysis.Combined with the VUV FEL,photodissociation of H2S at 122.95 nm was studied successfully.The TOF spectrum was measured and the derived total kinetic energy release spectrum was displayed.The results suggest that the experimental setup is a powerful tool for investigating photodissociation dynamics of molecules in the VUV region which involves the H-atom elimination processes.展开更多
The sluggish lithium-ion(Li-ion)transport kinetics in graphite anode hinders its application in fast-charging Li-ion batteries(LIBs).Here,we develop an ionpumping interphase(IPI)on graphdiyne(GDY)/graphite heterojunct...The sluggish lithium-ion(Li-ion)transport kinetics in graphite anode hinders its application in fast-charging Li-ion batteries(LIBs).Here,we develop an ionpumping interphase(IPI)on graphdiyne(GDY)/graphite heterojunction anodes to boost the ionic transport kinetics and enable high-performance,fast-charging LIBs.The IPI changed the ion solvation/desolvation environment by covalent/non-covalent interactions with Li ions or solvents to optimize solid-electrolyte interphase(SEI)and regulate Li-ion transport behavior.We studied the in situ growth of few-layer GDY on graphite surface(GDY/graphite)as the IPI and found that the strong interaction between GDY and Li ions enabled surface-induced modification of the ion solvation behavior and surface-assisted desolvation effect to accelerate the Li-ion desolvation process.A functional anion-derived SEI layer with improved Li-ion conductivity was created.Together with the generated built-in electric field at GDY/graphite hetero-interface self-pumping Li ions to intercalate into the graphite,the Li-ion transport kinetics was significantly enhanced to effectively eliminate Li plating and large voltage polarization of the graphite anodes.A fast Li intercalation in GDY/graphite without Li oversaturation at the edge of the graphite was directly observed.The superior performance with high capacity(139.2 mA h g^(-1))and long lifespan(1650 cycles)under extremely fast-charging conditions(20 C,1 C=372 mA g^(-1))was achieved on GDY/graphite anodes.Even at low temperatures(-20℃),a specific capacity of 128.4 mA h g^(-1) was achieved with a capacity retention of 80%after 500 cycles at a 2 C rate.展开更多
Recently,PbSnSe_(2)alloy was found to exhibit a large hysteresis effect on transport properties,demonstrating its significant potential for thermoelectric applications.Using ab initio approaches,we studied the carrier...Recently,PbSnSe_(2)alloy was found to exhibit a large hysteresis effect on transport properties,demonstrating its significant potential for thermoelectric applications.Using ab initio approaches,we studied the carrier transport properties of PbSnSe_(2)crystal,which is a special case of the alloy with the shortest-range order.A peak power factor of 134.2μW cm^(-1)K^(-2)was found along the crossplane direction in the n-type PbSnSe_(2)at a doping concentration of 7×10^(20)cm^(-3)at 700 K.This high power factor originates from delocalized p electrons between intra-plane Pb-Se pairs and between cross-plane Sn-Se pairs that can build up transport channels for conducting electrons,leading to a high electrical conductivity of 5.9×10^(5)S m^(-1).Introducing Pb atoms into Pnma phase SnSe can decrease the phonon group velocities and enhance the phonon-phonon scatterings,leading to a low thermal conductivity of 0.53 W m^(-1)K^(-1)at 700 K along the cross-plane direction.The calculated peak ZT of~3 along the cross-plane direction at an n-type doping concentration of around 5×10^(19)cm^(-3),which represents a theoretical upper limit for an idealized PbSnSe_(2)crystal.This work interprets the origins of three-dimensional charge and two-dimensional phonon transport behavior in PbSnSe_(2)and demonstrates that such crystals are promising high-performance thermoelectric semiconductors.展开更多
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (No.XDB17000000)the National Natural Science Foundation of China (NSFC Center for Chemical Dynamics (No.21688102)+4 种基金the National Natural Science Foundation of China (No.21673232, No.21873099, No.21922306)the International Partnership Program of Chinese Academy of Sci-ences (No.121421KYSB20170012)supported by the National Natural Science Foundation of China (No.21973010)supported by the National Natural Science Foundation of China (No.21773236)supported by the Natural Science Research Project of Education Department of Anhui Province (No.KJ2019A0521).
文摘Photodissociation of H2S in the VUV region plays an important role in the atmospheric chemistry and interstellar chemistry.To date,however,few studies have been focused on this topic.In this article,we have described a laser dispersion method applied in the apparatus combining the high-n H atom Rydberg tagging time-of-flight technique with the vacuum ultraviolet free electron laser(VUV FEL).The Lyman-αlaser beam(121.6 nm)used in the H-atom detection was generated by the difference frequency four-wave mixing schemes in a Kr/Ar gas cell.After passing through an off-axis biconvex LiF lens,the 121.6 nm beam was dispersed from the 212.6 nm and 845 nm beams due to the different deflection angles experienced by these laser beams at the surfaces of the biconvex lens.This method can eliminate the background signal from the 212.6 nm photolysis.Combined with the VUV FEL,photodissociation of H2S at 122.95 nm was studied successfully.The TOF spectrum was measured and the derived total kinetic energy release spectrum was displayed.The results suggest that the experimental setup is a powerful tool for investigating photodissociation dynamics of molecules in the VUV region which involves the H-atom elimination processes.
基金the National Nature Science Foundation of China(grant nos.52072222 and 22279073)the National Key Research and Development Project of China(grant no.2022YFA1200044)+2 种基金the Taishan Scholar Project of Shandong Province of China(grant no.62460082061017)the Natural Science Foundation of Shandong Province(grant no.ZR2022ZD35)the National Nature Science Foundation of China(grant nos.21790050 and 21790051).
文摘The sluggish lithium-ion(Li-ion)transport kinetics in graphite anode hinders its application in fast-charging Li-ion batteries(LIBs).Here,we develop an ionpumping interphase(IPI)on graphdiyne(GDY)/graphite heterojunction anodes to boost the ionic transport kinetics and enable high-performance,fast-charging LIBs.The IPI changed the ion solvation/desolvation environment by covalent/non-covalent interactions with Li ions or solvents to optimize solid-electrolyte interphase(SEI)and regulate Li-ion transport behavior.We studied the in situ growth of few-layer GDY on graphite surface(GDY/graphite)as the IPI and found that the strong interaction between GDY and Li ions enabled surface-induced modification of the ion solvation behavior and surface-assisted desolvation effect to accelerate the Li-ion desolvation process.A functional anion-derived SEI layer with improved Li-ion conductivity was created.Together with the generated built-in electric field at GDY/graphite hetero-interface self-pumping Li ions to intercalate into the graphite,the Li-ion transport kinetics was significantly enhanced to effectively eliminate Li plating and large voltage polarization of the graphite anodes.A fast Li intercalation in GDY/graphite without Li oversaturation at the edge of the graphite was directly observed.The superior performance with high capacity(139.2 mA h g^(-1))and long lifespan(1650 cycles)under extremely fast-charging conditions(20 C,1 C=372 mA g^(-1))was achieved on GDY/graphite anodes.Even at low temperatures(-20℃),a specific capacity of 128.4 mA h g^(-1) was achieved with a capacity retention of 80%after 500 cycles at a 2 C rate.
基金National Key Research and Development Program of China,Grant/Award Number:2022YFB3803900National Natural Science Foundation of China,Grant/Award Number:52076089。
文摘Recently,PbSnSe_(2)alloy was found to exhibit a large hysteresis effect on transport properties,demonstrating its significant potential for thermoelectric applications.Using ab initio approaches,we studied the carrier transport properties of PbSnSe_(2)crystal,which is a special case of the alloy with the shortest-range order.A peak power factor of 134.2μW cm^(-1)K^(-2)was found along the crossplane direction in the n-type PbSnSe_(2)at a doping concentration of 7×10^(20)cm^(-3)at 700 K.This high power factor originates from delocalized p electrons between intra-plane Pb-Se pairs and between cross-plane Sn-Se pairs that can build up transport channels for conducting electrons,leading to a high electrical conductivity of 5.9×10^(5)S m^(-1).Introducing Pb atoms into Pnma phase SnSe can decrease the phonon group velocities and enhance the phonon-phonon scatterings,leading to a low thermal conductivity of 0.53 W m^(-1)K^(-1)at 700 K along the cross-plane direction.The calculated peak ZT of~3 along the cross-plane direction at an n-type doping concentration of around 5×10^(19)cm^(-3),which represents a theoretical upper limit for an idealized PbSnSe_(2)crystal.This work interprets the origins of three-dimensional charge and two-dimensional phonon transport behavior in PbSnSe_(2)and demonstrates that such crystals are promising high-performance thermoelectric semiconductors.
