The Preparation And Electrochemical Performances Application Of Bismuth Sulfide/Carbon Electrodes

Bismuth usually in the form of free metals and minerals exist in earth. Bismuthinite and bismuth ocher are the main mineral. Bismuthinite belong with sulfide mineral, where Bi content of up to 81.3%, is an important raw material used to extract the Bi.Bismuth sulfide?Bi₂S₃? belong to the main group chalcogenides which have been widely known as a type of semiconductor due to its direct band gap?Eg=1.3eV? and many potential applications such as a photodiode, a photocatalyst, biological labels, electrochemical batteries which has been widely used in photoelectrochemical hydrogen storage and other fields. 3d orbitals of Bi₂S₃ can provide more electrons involved in the reaction of the electrode material, which makes the reaction capacity better. It makes Bi₂S₃ to be used as a new type of lithium-ion battery electrode materials.In this novel, Bismuthinite was raw material out of Bi?NO3?3·5H2O, then Bi₂S₃ electrode material was synthesized by hydrothermal method with Bi?NO3?3·5H2O and CH3CSNH2. Respectively Bi₂S₃/CNT, Bi₂S₃/GR composite electrode material was produced by hydrothermal which was modified by CNT and GR. Bi@C core–shell nanowires electrode material was prepared by Bi₂S₃ as the precursors in tube furnace. X-ray diffraction data were collected on an X-ray diffractometer.All of the electrode material was characterized by field-emission scanning electron microscopy and transmission electron microscopy. N2 sorption isotherms were measured with surface area and pore size obtained using Brunauer-Emmett-Teller?BET? and Barrett-Joyner-Halenda?BJH? methods. Thermogravimetric analysis was carried out using a thermogravimetric analyzer. The cycling performance of all electrode material was tested using a multi-channelled battery tester. The cyclic voltammetry and CV impedance were measured on electrochemical workstation. The contents are as follows:?1? The influence of the Bi?NO3?3·5H2O/CH3CSNH2 mole ratio, time and temperatures on the structure and electrochemical performances of Bi₂S₃ were studied and the optimal conditions were characterized. The results of XRD show that, on the condition of 1:10 Bi?NO3?3·5H2O/CH3CSNH2 120 oC, 12 h, the prepared materials was well-crystallized. The initial discharge capacity at 100mAg-1 of the material is 1021.9mAhg-1, the capacity retention of 50 cycles is tend to be 0.?2? Bi₂S₃ particles embrace CNT instead of scattering around which also lowers the contact impedance of the Bi₂S₃/CNT nanocomposite materials. The electrochemical test has proved our judgment for its superb cycling and rate performances. It could reach 204mAhg-1 after the current of 1000mAg-1, and retain 246.3mAhg-1 after 50 cycles.?3? The Bi₂S₃ particles in Bi₂S₃/GR composites were dispersed on the graphene nanosheets. Electrochemical tests show about Bi₂S₃/graphene composites exhibit an extraordinary capacity of 1248.9mAhg-1 with excellent cycling stability?50cycles, 343mAhg-1? and high rate capability?1000mAg-1, about 243mAhg-1? compared to pure Bi₂S₃ particles prepared by a similar route in the absence of graphene, suggesting a promising electrode material for lithium ion batteries.?4? Bi crystalline nanorods uniformly coated within a layer of amorphous carbon layer which has a large specific surface area?179.78cm3/g? and pore size?4.15nm?. Electrochemical tests showed about Bi@C composites exhibit an extraordinary capacity with excellent cycling stability?50 cycles, 343mAhg-1?.