Application Of Sulphur,Oxide/Carbon Composites In Electrochemical Energy Storage

The development of lithium-ion batteries requires high energy storage performance.It is important to develop electrode materials with high capacity and energy density.Based on the application of carbon in electrode materials of lithium-ion batteries,the preparation and electrochemical study of sulfur,oxide/carbon composites were carried out in this paper.Firstly,sulfur and porous carbon nanofiber film coated by reduced graphene oxide(rGO@S-PCNP)has been prepared by electrospinning and electrodeposition method,which can be directly used as cathode for lithium-sulfur batteries.The electrochemical tests show that rGO@S-PCNP with a sulfur loading of 1.5 mg cm-2 and a thickness of 130 ?m delivers an initial discharge capacity of 801.91 mAh g-1 at 0.1 C.After an activation process,the highest capacity of 708.8 mAh g-1 can be achieved at 52th cycle with the average coulombic efficiency of 97.1%and a small fading rate of 0.08%per cycle,exhibiting excellent cyclic stability,high coulomb efficiency and good rate performance.Secondly,the multistage core-shell Fe3O4-polypyrrole(Fe3O4-PPy)anode material for lithium-ion battery with different Fe3O4 contents has been successfully prepared by solvothermal,etching and in-situ polymerization.According to the results of characterization and electrochemical tests,it is found that,when the Fe3O4 content is 65.1%(Fe3O4-PPy-60),the initial coulombic efficiency of 74.8%and a larger discharge specific capacity of 450.7 mAh g-1 are achieved after 800 cycles at 2 C,demonstrating high rate and long cycle characteristic.Thirdly,an rGO coated carbon fiber thin film with spherical Cu2SnS3 has been obtained by gel solvothermal and electrodeposition method.Compared with the pure Cu2SnS3(CTS)and Cu2SnS3-CNF(CTS-CNF),the rGO@CTS-CNF binder-free electrode shows excellent electrochemical performance.Based on the mass of the whole electrode,the initial discharge capacity is 678.8 mAh g-1 at the current density of 0.5 A g-1,and the discharge capacity can be maintained as 464.2 mAh g-1 after 200 cycles,which can be 78.9%of the theoretical specific capacity,exhibiting high specific capacity and excellent cyclic stability.