MgH_(2) is a promising high-capacity solid-state hydrogen storage material,while its application is greatly hindered by the high desorption temperature and sluggish kinetics.Herein,intertwined 2D oxygen vacancy-rich V...MgH_(2) is a promising high-capacity solid-state hydrogen storage material,while its application is greatly hindered by the high desorption temperature and sluggish kinetics.Herein,intertwined 2D oxygen vacancy-rich V_(2)O_(5) nanosheets(H-V_(2)O_(5))are specifically designed and used as catalysts to improve the hydrogen storage properties of MgH_(2).The as-prepared MgH_(2)-H-V_(2)O_(5) composites exhibit low desorption temperatures(Tonset=185℃)with a hydrogen capacity of 6.54 wt%,fast kinetics(Ea=84.55±1.37 kJ mol^(-1) H_(2) for desorption),and long cycling stability.Impressively,hydrogen absorption can be achieved at a temperature as low as 30℃ with a capacity of 2.38 wt%within 60 min.Moreover,the composites maintain a capacity retention rate of~99%after 100 cycles at 275℃.Experimental studies and theoretical calculations demonstrate that the in-situ formed VH_(2)/V catalysts,unique 2D structure of H-V_(2)O_(5) nanosheets,and abundant oxygen vacancies positively contribute to the improved hydrogen sorption properties.Notably,the existence of oxygen vacancies plays a double role,which could not only directly accelerate the hydrogen ab/de-sorption rate of MgH_(2),but also indirectly affect the activity of the catalytic phase VH_(2)/V,thereby further boosting the hydrogen storage performance of MgH_(2).This work highlights an oxygen vacancy excited“hydrogen pump”effect of VH_(2)/V on the hydrogen sorption of Mg/MgH_(2).The strategy developed here may pave a new way toward the development of oxygen vacancy-rich transition metal oxides catalyzed hydride systems.展开更多
With the advantages of the multiple oxidation states and highly open crystal structures,vanadium-based composites have been considered as the promising cathode materials for aqueous zinc-ion batteries(ZIBs).However,th...With the advantages of the multiple oxidation states and highly open crystal structures,vanadium-based composites have been considered as the promising cathode materials for aqueous zinc-ion batteries(ZIBs).However,the inherent inferior electrical conductivity,low specific surface area,and sluggish Zn^(2+)diffusion kinetics of the traditional vanadium-based oxides have greatly impeded their development.Herein,a novel hierarchical porous spindle-shaped Ag-V_(2)O_(5) with unique heterostructures was rationally designed via a simple MOF-assisted synthetic method and applied as stable cathode for aqueous ZIBs.The high specific surface area and hierarchically porous superstructures endowed Ag-V_(2)O_(5) with sufficient electrochemical active sites and shortened the diffusion pathways of Zn^(2+),which was beneficial to accelerate the reversible transport of Zn^(2+)and deliver a high specific capacity(426 mA h g^(-1) at 0.1 A g^(-1) and 96.5%capacity retention after 100 cycles).Meanwhile,the self-built-in electric fields at the heterointerface of Ag-V_(2)O_(5) electrode could strengthen the synergistic coupling interaction between Ag and V_(2)O_(5),which can effectively enhance the electric conductivity and maintain the structural integrity,resulting in superb rate capability(326.1 mA h g^(-1) at 5.0 A g^(-1))and remarkable cycling stability(89.7%capacity retention after 2000 cycles at 5.0 A g^(-1)).Moreover,the reversible Zn^(2+)storage mechanism was further investigated and elucidated by kinetics analysis and DFT calculations.展开更多
基金supported by the National Natural Science Foundation of China (No.52004044)the Natural Science Foundation of Chongqing,China (No.CSTB2022NSCQ-MSX0801)+3 种基金the Foundation of Chongqing University of Science and Technology,China (No.ckrc2022030)the Graduate Research Innovation Project of Chongqing University of Science and Technology,China (No.YKJCX2220214)the Science and Technology Innovation Training Program of Chongqing University of Science and Technology,China (No.2022046)the College Students’Innovation and Entrepreneurship Training Program of Chongqing University of Science and Technology,China (No.2022007).
基金the support from the National Key Research&Development Program(2022YFB3803700)of ChinaNational Natural Science Foundation(No.52171186)the financial support from the Center of Hydrogen Science,Shanghai Jiao Tong University。
文摘MgH_(2) is a promising high-capacity solid-state hydrogen storage material,while its application is greatly hindered by the high desorption temperature and sluggish kinetics.Herein,intertwined 2D oxygen vacancy-rich V_(2)O_(5) nanosheets(H-V_(2)O_(5))are specifically designed and used as catalysts to improve the hydrogen storage properties of MgH_(2).The as-prepared MgH_(2)-H-V_(2)O_(5) composites exhibit low desorption temperatures(Tonset=185℃)with a hydrogen capacity of 6.54 wt%,fast kinetics(Ea=84.55±1.37 kJ mol^(-1) H_(2) for desorption),and long cycling stability.Impressively,hydrogen absorption can be achieved at a temperature as low as 30℃ with a capacity of 2.38 wt%within 60 min.Moreover,the composites maintain a capacity retention rate of~99%after 100 cycles at 275℃.Experimental studies and theoretical calculations demonstrate that the in-situ formed VH_(2)/V catalysts,unique 2D structure of H-V_(2)O_(5) nanosheets,and abundant oxygen vacancies positively contribute to the improved hydrogen sorption properties.Notably,the existence of oxygen vacancies plays a double role,which could not only directly accelerate the hydrogen ab/de-sorption rate of MgH_(2),but also indirectly affect the activity of the catalytic phase VH_(2)/V,thereby further boosting the hydrogen storage performance of MgH_(2).This work highlights an oxygen vacancy excited“hydrogen pump”effect of VH_(2)/V on the hydrogen sorption of Mg/MgH_(2).The strategy developed here may pave a new way toward the development of oxygen vacancy-rich transition metal oxides catalyzed hydride systems.
基金supported by the China Academy of Space Technology Innovation fund(2017ZY601026)。
文摘With the advantages of the multiple oxidation states and highly open crystal structures,vanadium-based composites have been considered as the promising cathode materials for aqueous zinc-ion batteries(ZIBs).However,the inherent inferior electrical conductivity,low specific surface area,and sluggish Zn^(2+)diffusion kinetics of the traditional vanadium-based oxides have greatly impeded their development.Herein,a novel hierarchical porous spindle-shaped Ag-V_(2)O_(5) with unique heterostructures was rationally designed via a simple MOF-assisted synthetic method and applied as stable cathode for aqueous ZIBs.The high specific surface area and hierarchically porous superstructures endowed Ag-V_(2)O_(5) with sufficient electrochemical active sites and shortened the diffusion pathways of Zn^(2+),which was beneficial to accelerate the reversible transport of Zn^(2+)and deliver a high specific capacity(426 mA h g^(-1) at 0.1 A g^(-1) and 96.5%capacity retention after 100 cycles).Meanwhile,the self-built-in electric fields at the heterointerface of Ag-V_(2)O_(5) electrode could strengthen the synergistic coupling interaction between Ag and V_(2)O_(5),which can effectively enhance the electric conductivity and maintain the structural integrity,resulting in superb rate capability(326.1 mA h g^(-1) at 5.0 A g^(-1))and remarkable cycling stability(89.7%capacity retention after 2000 cycles at 5.0 A g^(-1)).Moreover,the reversible Zn^(2+)storage mechanism was further investigated and elucidated by kinetics analysis and DFT calculations.
