A hot cathode bucket ion source is used for the EAST（experimental advanced superconducting tokamak）neutral beam injector.The thermal electrons emitted from the surface of the cathode are extracted and accelerated by...A hot cathode bucket ion source is used for the EAST（experimental advanced superconducting tokamak）neutral beam injector.The thermal electrons emitted from the surface of the cathode are extracted and accelerated by the electric field formed by the arc voltage,which is applied between the arc chamber of the ion source and the cathode.This paper analyzes the effects of arc voltage on the arc discharge in a hot cathode high current ion source.展开更多
La_（0.75）Mg_（0.25）Ni_（2.85）Co_（0.45–x）（AlSn）_x（AlSn）_x（x=0.0,0.1,0.2,0.3） alloys were prepared by magnetic induction melting method, and the phase composition and electrochemical properties were investi...La_（0.75）Mg_（0.25）Ni_（2.85）Co_（0.45–x）（AlSn）_x（AlSn）_x（x=0.0,0.1,0.2,0.3） alloys were prepared by magnetic induction melting method, and the phase composition and electrochemical properties were investigated systematically. The alloys were mainly composed of LaNi5, La2Ni7 and LaNi3 phase, and the cell volume of LaNi5 increased with the Al and Sn contents. For the alloy corresponding to x=0.0, the Cmax and C150 were 348.9 and 185 mA h/g, respectively, then for the alloy electrode with x=0.2, even though the Cmax was only 309.0 mA h/g less than 348.9 mA h/g, the C150 of 231 mA h/g was much higher than 185 mA h/g. And the values of the limit current density, anodic peak current density and hydrogen diffusion coefficient of the La0.75Mg0.25Ni2.85Co0.35（AlS n）0.1（x=0.1） alloy were 1079.5, 1023.8 mA /g and 5.71×10–10 cm2/s, respectively. Which were the highest than that of any other electrodes. These results suggested that the kinetic property of the La_（0.75）Mg_（0.25）Ni_（2.85）Co_（0.45–x）（AlSn）_x（AlSn）_x（x=0.0, 0.1, 0.2, 0.3） electrodes could be improved effectively by adding moderate contents of Al and Sn.展开更多
The use of seawater-based electrolytes in zinc-air batteries(S-ZABs)presents significant economic and social benefits and mitigates the demand for scarce freshwater resources.However,it is challenging to achieve a met...The use of seawater-based electrolytes in zinc-air batteries(S-ZABs)presents significant economic and social benefits and mitigates the demand for scarce freshwater resources.However,it is challenging to achieve a metal^(-)nitrogen-carbon(M-N-C)catalyst that exhibits high resistance to corrosive Cl^(-)in seawater-based electrolytes and possesses a strengthened binding affinity with O_(2),which enables catalysts with an optimized oxygen reduction reaction(ORR)and enhances the applicability of S-ZABs.Herein,we propose a combined wet chemistry-pyrolysis strategy to obtain atomically dispersed Fe-decorated nitrogen-doped mesoporous carbon spheres(N-MCS-Fe-900).Benefiting from the capacity of the Fe decorations to form the edge-hosted aerophilic FeN_(4)-O_(2)sites at the optimized three-phase interface,N-MCS-Fe-900 affords the enhanced resistance of the active Fe sites to corrosive Cl^(-),as well as improved interaction with O_(2),thereby facilitating the ORR process.As expected,the N-MCS-Fe-900 delivers high half wave potential of 0.90 V and kinetic current density of 18.61 mA cm^(-2)at 0.85 V in seawater-based 0.1 M KOH.More importantly,the S-ZABs equipped with N-MCS-Fe-900 exhibited long-term stability under a high current density for over 140 h without voltage decay.Theoretical calculations and electrochemical performance evaluations collectively revealed the superior catalytic efficacy and genesis of this activity in N-MCS-Fe-900,which features edge-hosted FeN_(4)-O_(2)sites at the stable three-phase interface in seawater electrolytes.This study provides new insights for the advancement of ORR catalysts in sustainable energy conversion technologies for seawater-based electrolytes.展开更多
Oxygen reduction reaction(ORR)plays an important role in the next-generation energy storage technologies,whereas it involves the sluggish and complicated proton-coupled electron transfer(PCET)steps that greatly limit ...Oxygen reduction reaction(ORR)plays an important role in the next-generation energy storage technologies,whereas it involves the sluggish and complicated proton-coupled electron transfer(PCET)steps that greatly limit the ORR kinetics.Therefore,it is urgent to construct an efficient catalyst that could simultaneously achieve the rapid oxygen-containing intermediates conversion and fast PCET process but remain challenging.Herein,the adjacent Fe_(3)C nanoparticles coupling with single Fe sites on the bubble-wrap-like porous N-doped carbon(Fe_(3)C@FeSA-NC)were deliberately constructed.Theoretical investigations reveal that the adjacent Fe_(3)C nanoparticles speed up the water dissociation and serve as proton-feeding centers for boosting the ORR kinetics of single Fe sites.Benefiting from the synergistic effect of the Fe_(3)C and single Fe sites,the Fe_(3)C@FeSA-NC affords an excellent half-wave potential of 0.88 V,and enables the assembled Zn-air batteries with the high peak power density of 164.5 mW·cm^(-2)and long-term stability of over 200 h at high current densities at 50 mA·cm^(-2).This work clarifies the mechanism for improving ORR kinetics of single atomic sites by engineering the adjacent proton-feeding centers,shedding light on the rational design of cost-effective electrocatalysts for energy conversion and storage technologies.展开更多
基金supported by the National Magnetic Confinement Fusion Science Program of China(No.2013GB101000)National Natural Science Foundation of China(No.11405207)
文摘A hot cathode bucket ion source is used for the EAST（experimental advanced superconducting tokamak）neutral beam injector.The thermal electrons emitted from the surface of the cathode are extracted and accelerated by the electric field formed by the arc voltage,which is applied between the arc chamber of the ion source and the cathode.This paper analyzes the effects of arc voltage on the arc discharge in a hot cathode high current ion source.
基金Project supported by the National Natural Science Foundation of China(51271061,51571065)Foundation of Guangxi Educational Committee(2013YB006)the Key Laboratory of Guangxi for Nonferrous Metals and Materials Processing Technology
文摘La_（0.75）Mg_（0.25）Ni_（2.85）Co_（0.45–x）（AlSn）_x（AlSn）_x（x=0.0,0.1,0.2,0.3） alloys were prepared by magnetic induction melting method, and the phase composition and electrochemical properties were investigated systematically. The alloys were mainly composed of LaNi5, La2Ni7 and LaNi3 phase, and the cell volume of LaNi5 increased with the Al and Sn contents. For the alloy corresponding to x=0.0, the Cmax and C150 were 348.9 and 185 mA h/g, respectively, then for the alloy electrode with x=0.2, even though the Cmax was only 309.0 mA h/g less than 348.9 mA h/g, the C150 of 231 mA h/g was much higher than 185 mA h/g. And the values of the limit current density, anodic peak current density and hydrogen diffusion coefficient of the La0.75Mg0.25Ni2.85Co0.35（AlS n）0.1（x=0.1） alloy were 1079.5, 1023.8 mA /g and 5.71×10–10 cm2/s, respectively. Which were the highest than that of any other electrodes. These results suggested that the kinetic property of the La_（0.75）Mg_（0.25）Ni_（2.85）Co_（0.45–x）（AlSn）_x（AlSn）_x（x=0.0, 0.1, 0.2, 0.3） electrodes could be improved effectively by adding moderate contents of Al and Sn.
基金supported by the National Natural Science Foundation of China(22309197,22279124,and 52261145700)the Natural Science Foundation of Shandong Province(ZR2022ZD30).
文摘The use of seawater-based electrolytes in zinc-air batteries(S-ZABs)presents significant economic and social benefits and mitigates the demand for scarce freshwater resources.However,it is challenging to achieve a metal^(-)nitrogen-carbon(M-N-C)catalyst that exhibits high resistance to corrosive Cl^(-)in seawater-based electrolytes and possesses a strengthened binding affinity with O_(2),which enables catalysts with an optimized oxygen reduction reaction(ORR)and enhances the applicability of S-ZABs.Herein,we propose a combined wet chemistry-pyrolysis strategy to obtain atomically dispersed Fe-decorated nitrogen-doped mesoporous carbon spheres(N-MCS-Fe-900).Benefiting from the capacity of the Fe decorations to form the edge-hosted aerophilic FeN_(4)-O_(2)sites at the optimized three-phase interface,N-MCS-Fe-900 affords the enhanced resistance of the active Fe sites to corrosive Cl^(-),as well as improved interaction with O_(2),thereby facilitating the ORR process.As expected,the N-MCS-Fe-900 delivers high half wave potential of 0.90 V and kinetic current density of 18.61 mA cm^(-2)at 0.85 V in seawater-based 0.1 M KOH.More importantly,the S-ZABs equipped with N-MCS-Fe-900 exhibited long-term stability under a high current density for over 140 h without voltage decay.Theoretical calculations and electrochemical performance evaluations collectively revealed the superior catalytic efficacy and genesis of this activity in N-MCS-Fe-900,which features edge-hosted FeN_(4)-O_(2)sites at the stable three-phase interface in seawater electrolytes.This study provides new insights for the advancement of ORR catalysts in sustainable energy conversion technologies for seawater-based electrolytes.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.52261145700 and 22279124)the Natural Science Foundation of Shandong Province(No.ZR2020ZD10)the Fundamental Research Funds for the Central Universities(No.202262010).
文摘Oxygen reduction reaction(ORR)plays an important role in the next-generation energy storage technologies,whereas it involves the sluggish and complicated proton-coupled electron transfer(PCET)steps that greatly limit the ORR kinetics.Therefore,it is urgent to construct an efficient catalyst that could simultaneously achieve the rapid oxygen-containing intermediates conversion and fast PCET process but remain challenging.Herein,the adjacent Fe_(3)C nanoparticles coupling with single Fe sites on the bubble-wrap-like porous N-doped carbon(Fe_(3)C@FeSA-NC)were deliberately constructed.Theoretical investigations reveal that the adjacent Fe_(3)C nanoparticles speed up the water dissociation and serve as proton-feeding centers for boosting the ORR kinetics of single Fe sites.Benefiting from the synergistic effect of the Fe_(3)C and single Fe sites,the Fe_(3)C@FeSA-NC affords an excellent half-wave potential of 0.88 V,and enables the assembled Zn-air batteries with the high peak power density of 164.5 mW·cm^(-2)and long-term stability of over 200 h at high current densities at 50 mA·cm^(-2).This work clarifies the mechanism for improving ORR kinetics of single atomic sites by engineering the adjacent proton-feeding centers,shedding light on the rational design of cost-effective electrocatalysts for energy conversion and storage technologies.
