AV4+-V2O5 cathode with mixed vanadium valences was prepared via a novel synthetic method using VOOH as the precursor,and its zinc-ion storage performance was evaluated.The products are hollow spheres consisting of nan...AV4+-V2O5 cathode with mixed vanadium valences was prepared via a novel synthetic method using VOOH as the precursor,and its zinc-ion storage performance was evaluated.The products are hollow spheres consisting of nanoflakes.The V4+-V2O5 cathode exhibits a prominent cycling performance,with a specific capacity of 140 mAhg-1 after 1000 cycles at 10 A g.1,and an excellent rate capability.The good electrochemical performance is attributed to the presence of V4+,which leads to higher electrochemical activity,lower polarization,faster ion diffusion,and higher electrical conductivity than V2O5 without V4+.This engineering strategy of valence state manipulation may pave the way for designing high-performance cathodes for elucidating advanced battery chemistry.展开更多
Vanadium oxides with a layered structure are promising candidates for both lithium-ion batteries and sodium-ion batteries （SIBs）. The self-template approach, which involves a transformation from metal-organic framew...Vanadium oxides with a layered structure are promising candidates for both lithium-ion batteries and sodium-ion batteries （SIBs）. The self-template approach, which involves a transformation from metal-organic frameworks （MOFs） into porous metal oxides, is a novel and effective way to achieve desirable electrochemical performance. In this stud~ porous shuttle-like vanadium oxides （i.e., V205, V203/C） were successfully prepared by using MIL-88B （V） as precursors with a specific calcination process. As a proof-of-concept application, the as- prepared porous shuttle-like VaOdC was used as an anode material for SIBs. The porous shuttle-like V203/C, which had an inherent layered structure with metallic behavior, exhibited excellent electrochemical properties. Remarkable rate capacities of 417, 247, 202, 176, 164, and 149 mAh.g-1 were achieved at current densities of 50, 100, 200, 500, 1,000, and 2,000 mA.g-1, respectively. Under cycling at 2 A.g-1, the specific discharge capacity reached 181 mAh.g-1, with a low capacity fading rate of 0.032% per cycle after 1,000 cycles. Density functional theory calculation results indicated that Na ions preferred to occupy the interlamination rather than the inside of each layer in the V203. Interestingly, the special layered structure with a skeleton of dumbbell-like V-V bonds and metallic behavior was maintained after the insertion of Na ions, which was beneficial for the cycle performance. We consider that the MOF precursor of MIL-88B （V） can be used to synthesize other porous V-based materials for various applications.展开更多
基金supported by National Natural Science Foundation of China(Nos.51802356,51872334,and 51572299)Innovation-Driven Project of Central South University(No.2018CX004)
文摘AV4+-V2O5 cathode with mixed vanadium valences was prepared via a novel synthetic method using VOOH as the precursor,and its zinc-ion storage performance was evaluated.The products are hollow spheres consisting of nanoflakes.The V4+-V2O5 cathode exhibits a prominent cycling performance,with a specific capacity of 140 mAhg-1 after 1000 cycles at 10 A g.1,and an excellent rate capability.The good electrochemical performance is attributed to the presence of V4+,which leads to higher electrochemical activity,lower polarization,faster ion diffusion,and higher electrical conductivity than V2O5 without V4+.This engineering strategy of valence state manipulation may pave the way for designing high-performance cathodes for elucidating advanced battery chemistry.
文摘Vanadium oxides with a layered structure are promising candidates for both lithium-ion batteries and sodium-ion batteries （SIBs）. The self-template approach, which involves a transformation from metal-organic frameworks （MOFs） into porous metal oxides, is a novel and effective way to achieve desirable electrochemical performance. In this stud~ porous shuttle-like vanadium oxides （i.e., V205, V203/C） were successfully prepared by using MIL-88B （V） as precursors with a specific calcination process. As a proof-of-concept application, the as- prepared porous shuttle-like VaOdC was used as an anode material for SIBs. The porous shuttle-like V203/C, which had an inherent layered structure with metallic behavior, exhibited excellent electrochemical properties. Remarkable rate capacities of 417, 247, 202, 176, 164, and 149 mAh.g-1 were achieved at current densities of 50, 100, 200, 500, 1,000, and 2,000 mA.g-1, respectively. Under cycling at 2 A.g-1, the specific discharge capacity reached 181 mAh.g-1, with a low capacity fading rate of 0.032% per cycle after 1,000 cycles. Density functional theory calculation results indicated that Na ions preferred to occupy the interlamination rather than the inside of each layer in the V203. Interestingly, the special layered structure with a skeleton of dumbbell-like V-V bonds and metallic behavior was maintained after the insertion of Na ions, which was beneficial for the cycle performance. We consider that the MOF precursor of MIL-88B （V） can be used to synthesize other porous V-based materials for various applications.
