The L-cysteine-assisted Synthesis And The Electrochemical Performance Research Of The Nickel-based Sulphide

In recent years, high capacity batteries have attracted intensive interest because of their various applications in automobiles, electronics, vehicles etc. Lithium ion battery has the characteristics of large capacity, long cycle life and no pollution and cathode material is the key point to determine the capacity of lithium ion battery. As cathode material, sulfur-based material has been seen as a good substitution for LiCoO2, Owing to their high theoretical specific capacity. Nickel-based sulphide is the most attractive one, because it has not only high theoretical capacity but also high conductivity.With the introduction of L- cysteine, the process of controlled synthesis of nickel sulphide micro-spheres with different morphologies was greatly simplified by hydrothermal method. And nickel sulphide hollow micro-sphere and laminated flower micro-particle was synthesized. Then, nickel sulphide doped with Fe3+ and nickel sulphide/carbon composite was preparaed to improve electrochemical cycling stability.With the introduction of L- cysteine, nickel sulphide hollow micronsphere and laminated flower micron particle was synthesized by hydrothermal method. Possible formation mechanism was get:the formation of precursor complexes, the bond-breaking nucleation and the preferential growth into different structure, by analyzing XRD and SEM results of the products under different hydrothermal reaction condition. The results showed that nickel sulphide hollow microspheres have better cycle stability.By doping a higher valenced metal cation (Fe3+), material with a high electrochemical stability was obtained. On the basis of preliminary experiments, the hydrothermal conditions for preparing a material with better electrochemical cycling properties were getting. We synthesized the nickel sulphide doped with different amounts of Fe3+. And the electrochemical performance test results indicate that the nickel sulphide doped with 20mol% of Fe3+ has a best electrochemical performance than the nickel sulphide hollow microspheres.By adding glucose, nickel sulphide/carbon composite with a high electrochemical stability was obtained. On the basis of preliminary experiments, the hydrothermal conditions for preparing a material with better electrochemical cycling properties were getting. We synthesized the nickel sulphide/carbon composite with different carbon content. And the electrochemical performance test results indicate that the nickel sulphide/carbon composite with 50% of carbon has a best electrochemical performance. It’s initial discharge capacity reached 625.3mAh/g, and the specific capacity remains 100mAh/g after 100 charge/discharge cycling. It can be concluded that the nickel sulphide/carbon composite with the Ni:glucose (wt%)=1:5 has a best electrochemical performance than the Nickel Sulfide hollow microspheres and Nickel Sulfide doped with 20mol% Fe3+.