In this study, a boron-doped microporous carbon （BMC）/sulfur nanocomposite is synthesized and applied as a novel cathode material for advanced Li-S batteries. The cell with this cathode exhibits an ultrahigh cycling...In this study, a boron-doped microporous carbon （BMC）/sulfur nanocomposite is synthesized and applied as a novel cathode material for advanced Li-S batteries. The cell with this cathode exhibits an ultrahigh cycling stability and rate capability. After activation, a capacity of 749.5 mAh/g was obtained on the 54t＂ cycle at a discharge current of 3.2 A/g. After 500 cycles, capacity of 561.8 mAh/g remained （74.96% retention）, with only a very small average capacity decay of 0.056%. The excellent reversibility and stability of the novel sulfur cathode can be attributed to the ability of the boron-doped microporous carbon host to both physically confine polysulfides and chemically bind these species on the host surface. Theoretical calculations confirm that boron-doped carbon is capable of significantly stronger interactions with the polysulfide species than undoped carbon, most likely as a result of the lower electronegativity of boron. We believe that this doping strategy can be extended to other metal-air batteries and fuel cells, and that it has promising potential for many different applications.展开更多
Hybrid ion capacitors have been considered as a very attractive energy source with high energy density and power density since it combines both merits of lithium ion batteries and supercapacitors. However,their commer...Hybrid ion capacitors have been considered as a very attractive energy source with high energy density and power density since it combines both merits of lithium ion batteries and supercapacitors. However,their commercial application has been limited by the mismatch of charge-storage capacity and electrode kinetics between the capacitor-type cathode and battery-type anode. Herein, B and N dual-doped 3D superstructure carbon cathode is prepared through a facile template method. It delivers a high specific capacity, excellent rate capability and good cycling stability due to the B, N dual-doping, which has a profound effect in control the porosity, functional groups, and electronic conductivity for the carbon cathode. The hybrid ion capacitors using B, N dual-doping carbon cathode and prelithiated graphite anode show a high energy density of 115.5 Wh/kg at 250 W/kg and remain about 53.6 Wh/kg even at a high power density of 10 kW/kg. Additionally, the novel hybrid device achieves 76.3% capacity retention after 2000 cycles tested at 1250 W/kg power density. Significantly, the simultaneous manipulation of heteroatoms in carbon materials provides new opportunities to boost the energy and power density for hybrid ion capacitors.展开更多
Boron-doped hydrogenated silicon films with different gaseous doping ratios（B2H6/SiH4） were deposited in a plasma-enhanced chemical vapor deposition（PECVD） system.The microstructure of the films was investigated b...Boron-doped hydrogenated silicon films with different gaseous doping ratios（B2H6/SiH4） were deposited in a plasma-enhanced chemical vapor deposition（PECVD） system.The microstructure of the films was investigated by atomic force microscopy（AFM） and Raman scattering spectroscopy.The electrical properties of the films were characterized by their room temperature electrical conductivity（σ） and the activation energy（Ea）.The results show that with an increasing gaseous doping ratio,the silicon films transfer from a microcrystalline to an amorphous phase,and corresponding changes in the electrical properties were observed.The thin boron-doped silicon layers were fabricated as recombination layers in tunnel junctions.The measurements of the I-V characteristics and the transparency spectra of the junctions indicate that the best gaseous doping ratio of the recombination layer is 0.04,and the film deposited under that condition is amorphous silicon with a small amount of crystallites embedded in it.The junction with such a recombination layer has a small resistance,a nearly ohmic contact,and a negligible optical absorption.展开更多
In this paper, the effects of different boron (nitrogen)-doping on the electronic properties of blue phosphorene have been investigated by the first-</span></span><span><span><span style=&qu...In this paper, the effects of different boron (nitrogen)-doping on the electronic properties of blue phosphorene have been investigated by the first-</span></span><span><span><span style="font-family:""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">principles calculations. We have taken eight doping configurations into account, the calculated results show that the bond length of P-B is decreasing with the doping concentration increasing. For the four boron atoms doping configuration, the geometric structure appears the distinct distortion. The band gap is decreasing with the doping concentration increasing, and it appears the transition from indirect band gap to direct band gap for boron doping configurations. It is hoped that the calculated results may be useful for designing electronic devices based on blue phosphorene.展开更多
文摘In this study, a boron-doped microporous carbon （BMC）/sulfur nanocomposite is synthesized and applied as a novel cathode material for advanced Li-S batteries. The cell with this cathode exhibits an ultrahigh cycling stability and rate capability. After activation, a capacity of 749.5 mAh/g was obtained on the 54t＂ cycle at a discharge current of 3.2 A/g. After 500 cycles, capacity of 561.8 mAh/g remained （74.96% retention）, with only a very small average capacity decay of 0.056%. The excellent reversibility and stability of the novel sulfur cathode can be attributed to the ability of the boron-doped microporous carbon host to both physically confine polysulfides and chemically bind these species on the host surface. Theoretical calculations confirm that boron-doped carbon is capable of significantly stronger interactions with the polysulfide species than undoped carbon, most likely as a result of the lower electronegativity of boron. We believe that this doping strategy can be extended to other metal-air batteries and fuel cells, and that it has promising potential for many different applications.
基金financial support from the National Program on Key Basic Research Project of China (No. 2014CB239701)the National Natural Science Foundation of China (Nos. 51372116, 51672128, 21773118)+1 种基金Prospective Joint Research Project of Cooperative Innovation Fund of Jiangsu Province (No. BY2015003-7)Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)
文摘Hybrid ion capacitors have been considered as a very attractive energy source with high energy density and power density since it combines both merits of lithium ion batteries and supercapacitors. However,their commercial application has been limited by the mismatch of charge-storage capacity and electrode kinetics between the capacitor-type cathode and battery-type anode. Herein, B and N dual-doped 3D superstructure carbon cathode is prepared through a facile template method. It delivers a high specific capacity, excellent rate capability and good cycling stability due to the B, N dual-doping, which has a profound effect in control the porosity, functional groups, and electronic conductivity for the carbon cathode. The hybrid ion capacitors using B, N dual-doping carbon cathode and prelithiated graphite anode show a high energy density of 115.5 Wh/kg at 250 W/kg and remain about 53.6 Wh/kg even at a high power density of 10 kW/kg. Additionally, the novel hybrid device achieves 76.3% capacity retention after 2000 cycles tested at 1250 W/kg power density. Significantly, the simultaneous manipulation of heteroatoms in carbon materials provides new opportunities to boost the energy and power density for hybrid ion capacitors.
基金the National Basic Research Program of China (No.2006CB202602, 2006CB202603)Tianjin Assistant Foundation for the National Basic Research Program of China (07QTPTJC29500 )Doctor Start-up Foundation of Nankai University (No.J02048).
基金supported by the State Key Development Program for Basic Research of China(No.2006CB202604)the National Natural Science Foundation of China (No. 60576036)the National High Technology Research and Development Program of China (No. 2006AA05Z405)
文摘Boron-doped hydrogenated silicon films with different gaseous doping ratios（B2H6/SiH4） were deposited in a plasma-enhanced chemical vapor deposition（PECVD） system.The microstructure of the films was investigated by atomic force microscopy（AFM） and Raman scattering spectroscopy.The electrical properties of the films were characterized by their room temperature electrical conductivity（σ） and the activation energy（Ea）.The results show that with an increasing gaseous doping ratio,the silicon films transfer from a microcrystalline to an amorphous phase,and corresponding changes in the electrical properties were observed.The thin boron-doped silicon layers were fabricated as recombination layers in tunnel junctions.The measurements of the I-V characteristics and the transparency spectra of the junctions indicate that the best gaseous doping ratio of the recombination layer is 0.04,and the film deposited under that condition is amorphous silicon with a small amount of crystallites embedded in it.The junction with such a recombination layer has a small resistance,a nearly ohmic contact,and a negligible optical absorption.
文摘In this paper, the effects of different boron (nitrogen)-doping on the electronic properties of blue phosphorene have been investigated by the first-</span></span><span><span><span style="font-family:""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">principles calculations. We have taken eight doping configurations into account, the calculated results show that the bond length of P-B is decreasing with the doping concentration increasing. For the four boron atoms doping configuration, the geometric structure appears the distinct distortion. The band gap is decreasing with the doping concentration increasing, and it appears the transition from indirect band gap to direct band gap for boron doping configurations. It is hoped that the calculated results may be useful for designing electronic devices based on blue phosphorene.
