The two-dimensional(2D)layered material molybdenum disulfide(MoS_(2))exhibits a special Mo-S-Mo sandwich structure with a rather large spacing,making it a promising candidate as an anode material for sodium storage ap...The two-dimensional(2D)layered material molybdenum disulfide(MoS_(2))exhibits a special Mo-S-Mo sandwich structure with a rather large spacing,making it a promising candidate as an anode material for sodium storage applications.Unfortunately,the practical applications are limited by their intrinsically low electrical conductivity,significant volume alteration and severe particle agglomeration.In this study,we designed a new two-step solvothermal strategy to synthesize ultrathin nanosheetassembled MoS_(2)hollow nanospheres strongly located onlignite-based carbon(MoS_(2)/C)without any template.The ultrathin nanosheets assembled into hollow structures mitigated the volume changes of MoS_(2)during the(dis)-charge cycles,facilitated Na+diffusion,and reduced the migration energy barrier within MoS_(2).Lignite-based C enhances the electrical conductivity of MoS_(2),prevents its aggregation,and alleviates mechanical stress during repeated(dis)charging.The resultant hollow spherical MoS_(2)/C composite exhibits outstanding cyclability and rate performance when used as an anode in sodium-ion batteries,as it delivers a high specific capacity of 515.8 mAh g^(-1)after 1000 cycles at 1.0 A g^(-1),with a 94.34%capacity retention rate.Even at a high current density of 20 Ag^(-1),a capacity of 431 mAh g^(-1)can still be obtained after 2000cycles.In particular,the initial Coulombic efficiency of the MoS_(2)anode is markedly enhanced by the incorporation of lignite-based C.展开更多
A new coal staged conversion poly-generation system combined coal combustion and pyrolysis has been developed for clean and high efficient utilization of coal.Coal is the first pyrolysed in a fluidized pyrolyzer.The p...A new coal staged conversion poly-generation system combined coal combustion and pyrolysis has been developed for clean and high efficient utilization of coal.Coal is the first pyrolysed in a fluidized pyrolyzer.The pyrolysis gas is then purified and used for chemical product or liquid fuel production.Tar is collected during purification and can be processed to extract high value product and to make liquid fuels by hydro-refining.Semi-coke from the pyrolysis reactor is burned in a circulating fluidized bed(CFB)combustor for heat or power generation.The system can realize coal multiproduct generation and has a great potential to increase coal utilization value.A 1 MW poly-generation system pilot plant and a 12 MW CFB gas,tar,heat and power poly-generation system was erected.The experimental study focused on the two fluidized bed operation and characterization of gas,tar and char yields and compositions.The results showed that the system could operate stable,and produce about 0.12 m^(3)/kg gas with 22 MJ/m^(3)heating value and about 10 wt%tar when using Huainan bituminous coal under pyrolysis temperature between 500 and 600℃.The produced gases were mainly H_(2),CH_(4),CO,CO_(2),C_(2)H_(4),C_(2)H_(6),C_(3)H_(6)and C_(3)H_(8).The CFB combustor can burn semi-coke steadily.The application prospect of the new system was discussed.展开更多
Supercritical water gasification driven by solar energy is a promising way for clean utilization of biomass with high moisture content, but direct discharge of liquid residual causes energy waste and decreases energy ...Supercritical water gasification driven by solar energy is a promising way for clean utilization of biomass with high moisture content, but direct discharge of liquid residual causes energy waste and decreases energy efficiency. To reduce energy waste, a poly-generation system for hydrogen-rich gas production coupling heat supply and power generation based on supercritical water gasification of biomass driven by concentrated solar energy was established in this paper, which also provided a novel energy storage method to overcome the shortcomings of solar discontinuity. Thermodynamic model of the system was proposed and life cycle assessment(LCA) of the system was conducted. Influence of different parameters(temperature of 600℃ to 800℃, outlet temperature of heat exchanger of 42℃ to 56℃, biomass slurry concentration of 5% to 6.5%) on the gasification performance, energy and exergy efficiency, energy distribution and global warming potential(GWP) was discussed. The results indicated that hydrogen yield increased as gasification temperature increased since free radical reaction was enhanced which gas production reaction was classified into. Molar fraction of hydrogen increased as gasification temperature increased and reached 65.6% at 750℃. Energy and exergy efficiency of the system reached 74.84% and 34.87% at 700℃ and 600℃ respectively and that of gas production was 18.15% at 650℃, which was the highest. Increasing reaction temperature and decreasing biomass slurry concentration were effective ways to decrease GWP. Optimal operating parameter was reaction temperature of 650℃, outlet temperature of heat exchanger of 50℃ and biomass concentration of 5%.展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.51962027 and 21968022)the Major Science and Technology Project of Inner Mongolia Autonomous Region(No.2021ZD0016)+5 种基金the National Key R&D Program of China(No.2020YFC1909105)the Program for Young Talents of Science and Technology in Universities of Inner Mongolia Autonomous Region(No.NJYT24002)the Central Guidance Fund for Local Scientific and Technological Development(No.2024ZY0012)the Key Project of Tianjin Natural Science Foundation(No.23JCZDJC00570)the Special Funding of China Postdoctoral Science Foundation(No.2023T160268)the China Postdoctoral Science Foundation(No.2023M741362)
文摘The two-dimensional(2D)layered material molybdenum disulfide(MoS_(2))exhibits a special Mo-S-Mo sandwich structure with a rather large spacing,making it a promising candidate as an anode material for sodium storage applications.Unfortunately,the practical applications are limited by their intrinsically low electrical conductivity,significant volume alteration and severe particle agglomeration.In this study,we designed a new two-step solvothermal strategy to synthesize ultrathin nanosheetassembled MoS_(2)hollow nanospheres strongly located onlignite-based carbon(MoS_(2)/C)without any template.The ultrathin nanosheets assembled into hollow structures mitigated the volume changes of MoS_(2)during the(dis)-charge cycles,facilitated Na+diffusion,and reduced the migration energy barrier within MoS_(2).Lignite-based C enhances the electrical conductivity of MoS_(2),prevents its aggregation,and alleviates mechanical stress during repeated(dis)charging.The resultant hollow spherical MoS_(2)/C composite exhibits outstanding cyclability and rate performance when used as an anode in sodium-ion batteries,as it delivers a high specific capacity of 515.8 mAh g^(-1)after 1000 cycles at 1.0 A g^(-1),with a 94.34%capacity retention rate.Even at a high current density of 20 Ag^(-1),a capacity of 431 mAh g^(-1)can still be obtained after 2000cycles.In particular,the initial Coulombic efficiency of the MoS_(2)anode is markedly enhanced by the incorporation of lignite-based C.
基金This work was supported by the National High technology Research and Development Program of China(863 Pro-gram)(No.2007AA05Z334,2013AA051203)International Cooper-ation Project(2011DFR60190)the program of introducing talents of discipline to University(B08026).
文摘A new coal staged conversion poly-generation system combined coal combustion and pyrolysis has been developed for clean and high efficient utilization of coal.Coal is the first pyrolysed in a fluidized pyrolyzer.The pyrolysis gas is then purified and used for chemical product or liquid fuel production.Tar is collected during purification and can be processed to extract high value product and to make liquid fuels by hydro-refining.Semi-coke from the pyrolysis reactor is burned in a circulating fluidized bed(CFB)combustor for heat or power generation.The system can realize coal multiproduct generation and has a great potential to increase coal utilization value.A 1 MW poly-generation system pilot plant and a 12 MW CFB gas,tar,heat and power poly-generation system was erected.The experimental study focused on the two fluidized bed operation and characterization of gas,tar and char yields and compositions.The results showed that the system could operate stable,and produce about 0.12 m^(3)/kg gas with 22 MJ/m^(3)heating value and about 10 wt%tar when using Huainan bituminous coal under pyrolysis temperature between 500 and 600℃.The produced gases were mainly H_(2),CH_(4),CO,CO_(2),C_(2)H_(4),C_(2)H_(6),C_(3)H_(6)and C_(3)H_(8).The CFB combustor can burn semi-coke steadily.The application prospect of the new system was discussed.
基金This work was supported by the National Natural Science Foundation of China(NSFC)(No.51888103)National Natural Science Foundation of China(Grant No.51776169)the National Key R&D Program of China(Grant No.2016YFB0600100).
文摘Supercritical water gasification driven by solar energy is a promising way for clean utilization of biomass with high moisture content, but direct discharge of liquid residual causes energy waste and decreases energy efficiency. To reduce energy waste, a poly-generation system for hydrogen-rich gas production coupling heat supply and power generation based on supercritical water gasification of biomass driven by concentrated solar energy was established in this paper, which also provided a novel energy storage method to overcome the shortcomings of solar discontinuity. Thermodynamic model of the system was proposed and life cycle assessment(LCA) of the system was conducted. Influence of different parameters(temperature of 600℃ to 800℃, outlet temperature of heat exchanger of 42℃ to 56℃, biomass slurry concentration of 5% to 6.5%) on the gasification performance, energy and exergy efficiency, energy distribution and global warming potential(GWP) was discussed. The results indicated that hydrogen yield increased as gasification temperature increased since free radical reaction was enhanced which gas production reaction was classified into. Molar fraction of hydrogen increased as gasification temperature increased and reached 65.6% at 750℃. Energy and exergy efficiency of the system reached 74.84% and 34.87% at 700℃ and 600℃ respectively and that of gas production was 18.15% at 650℃, which was the highest. Increasing reaction temperature and decreasing biomass slurry concentration were effective ways to decrease GWP. Optimal operating parameter was reaction temperature of 650℃, outlet temperature of heat exchanger of 50℃ and biomass concentration of 5%.
