| "Energy crisis" and "environmental pollution" are the two major challenges today. In order to meet the growing demand for energy, improving the status of environment deteriorating, developing new energy sources without pollution and enriching resources have become the most important problems to be solved. As an efficient green clean energy, Lithium and Sodium ion batteries have a good cycle stability and high energy density, and gradually become a reliable alternative to replace the traditional energy sources. As the traditional cathode material of lithium ion battery, graphite still has many problems, such as low theoretical capacity, unsafe and so on. Due to the layer spacing of graphite is small, it is not suitable for sodium ion batteries. Therefore, developing of anode materials with long cycle life, high theoretical capacity and good safety performance have become the hotspot of research. In recent years, semiconductor materials have received extensive attention as the negative electrode of lithium and sodium ion batteries, and got some progress. Studies found that the preparation of nanomaterials with special morphology by adjusting control, and they can effectively improve the electrochemical properties. The compound of semiconductor materials and carbon to form semiconductor carbon composite materials can greatly improve the conductivity of the semiconductor. This measurement can ease the volume expansion of the material during the charge and discharge process, so that the electrochemical stability and safety of the materials will be improved. In this paper, we made the carbon composite treatment of the three kinds of semiconductor materials, TiO2, MoS2 and MoO2, with three different methods, respectively. The active materials were assembled into button cells as a negative electrode active material for lithium or sodium ion batteries to explore their electrochemical properties. The main research contents the following aspects:(1) The second chapter of the paper, we introduced the structure and electrochemical properties of TiO2 and TiO2@C nanosheets as a cathode active material of lithium ion batterys. As shown in SEM and TEM, the TiO2 nanosheet shows a uniform morphology and well dispersion with a particle size of about 40 nm. The carbon coating did not change the morphology and dispersion significantly. The performance test shows that carbon coating improved the specific capacity and rate performance of TiO2 materials.(2) The third chapter of the paper, we synthesized the C/MoS2 nanoflower composite material by a simple hydrothermal method with N-droped Carbon material of the special Zeolite imidazole skeleton structure. The test result shows that, the specific capacity for the firsy cycle of the C/MoS2 composite was 611mAh g-1. Compared with pure MoS2 and N-droped Carbon material, the C/MoS2 composite shows good cycle stability.(3) In the fourth chapter of the paper, we synthesized the C/MoO2 nanoflower material by a simple grinding and annealing method. The C/MoO2 nanoparticles were synthesized by controlling the amount of carbon doped, and made some comparision compared with the C/MoO2 nanoflower structure. Results indicated that the electrochemical performance was decreased with the amount of carbon doped. Therefore the C/MoO2 nanoflower material showed a better electrochemical performance. |
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