Preparations And Lithium-storage Properties Of Flexible And Free-standing Composites Based On Prussian Blue And Its Derivatives

Nowadays,the design and development of lithium-ion batteries?LIBs?with high energy density and long cycling life is one of the key scientific issues.The CC/FeFe?CN?₆,3DGN/FeFe?CN?₆ and 3DGN/Fe₄[Fe?CN?₆]₃ composites were prepared by in-situ synthesis method,based on three-dimensional?3D?graphene or carbon cloth?CC?as the substrates and Pussian blue as active materials.Then,the corresponding derivatives were further synthesized after the high-temperature calcination.The structures and physical properties of all these materials were characterized systematically by X-ray diffraction,electron microscopes,energy-dispersive spectrum,X-ray photoelectron energy spectrum and specific surface spectrometer,etc.The electrochemical performances of these materials were studied.Based on the systematical characterizations,the relationships between the composition,microstructure,conductivity,and porosity of electrode materials and their lithium-storage properties were explored in detail.This research provides new idea for the development of integrated electrodes with intriguing structure and high performance.The contents are as follows:1.The CC/FeFe?CN?₆ composite was prepared after the in-situ growth of Fe-MOF?FeFe?CN?₆?crystals on the CC surface by the solution immersion.The flexible and free-standing CC/Fe₂O₃ composite was further prepared after the high-temperature calcination.The CC/Fe₂O₃ composite can be directly employed as anode for LIBs,and exhibited a superior electrochemical property to pure CC and Fe₂O₃.In detail,the specific capacity of CC/Fe₂O₃ was 408 mAh g^-1 at a current density of 100 mA g^-1,and remained almost unchanged after 135 cycles.Even at a current density of 1 A g^-1,the capacity still reached to 110 mAh g^-1.The superior lithium-storage performance for the composite can be ascribe to the synergetic effect between CC and Fe₂O₃components.2.The 3DGN/FeFe?CN?₆ composite was prepared after the in-situ growth of Fe-MOF?FeFe?CN?₆?crystals on the 3DGN surface by the solution immersion.Then the flexible and free-standing 3DGN/Fe₂O₃ composite was further prepared after the high-temperature calcination.The resulting 3DGN/FeFe?CN?₆ and 3DGN/Fe₂O₃composites can be directly employed as anodes for LIBs,and exhibited superior electrochemical properties to pure 3DGN and FeFe?CN?₆?or Fe₂O₃?.In detail,the specific capacity of 3GDN/FeFe?CN?₆ was 512 mAh g^-1 at 100 mA g^-1,and remained almost unchanged after 150 cycles.Also,the capacity still reached to 150 mAh g^-1 at1 A g^-1.In comparison,the specific capacity of 3GDN/Fe₂O₃ was 604 mAh g^-1 at 100mA g^-1,and remained almost unchanged after 200 cycles.The capacity still has a value of 210 mAh g^-1 at 1 A g^-1.The superior lithium-storage performance for the composites can be attributed to the synergetic effect between 3DGN and FeFe?CN?₆?or Fe₂O₃?components.3.The 3DGN/Fe₄[Fe?CN?₆]₃ composite was prepared after the in-situ growth of Fe-MOF?Fe₄[Fe?CN?₆]₃?crystals on the 3DGN surface by the solution immersion.The flexible and free-standing 3DGN/Fe₂O₃ composite was further prepared after the high-temperature calcination.The resulting 3DGN/Fe₄[Fe?CN?₆]₃ and 3DGN/Fe₂O₃composites can be directly employed as anodes for LIBs,and exhibited superior electrochemical properties to pure 3DGN and Fe₄[Fe?CN?₆]₃?or Fe₂O₃?.In detail,the specific capacity of 3GDN/Fe₄[Fe?CN?₆]₃ was 382 mAh g^-1 at 100 mA g^-1,and remained almost unchanged after 90 cycles.Also,the capacity still reached to 300mAh g^-1 at 1 A g^-1.In comparison,the specific capacity of 3GDN/Fe₂O₃ was 504 mAh g^-1 at 100 mA g^-1,and remained almost unchanged after 240 cycles.The capacity still reached to 350 mAh g^-1 at 1 A g^-1.The superior lithium-storage performance for the composites can be attributed to the synergetic effect between 3DGN and Fe₄[Fe?CN?₆]₃?or Fe₂O₃?components.