Lithium-ion batteries are gradually widely used in portable electronic products and electric vehicles because of their high energy density, long cycle life and environmental protection. At present, the capacity of lithium-ion battery with graphite as negative electrode can not meet the requirements of long battery life of electric vehicles. Silicon-based materials have large specific capacity, low discharge platform and rich energy storage, and are the most potential anode materials for the next generation lithium batteries. However, the commercial application of silicon-based materials is seriously limited by its own factors. Firstly, the volume changes greatly in the process of lithium intercalation, which easily leads to particle pulverization, active substances leave the current collector, and SEI films are constantly produced, which eventually leads to the decline of electrochemical performance, as shown in figure 1, which is a schematic diagram of the failure mechanism of silicon; In addition, the conductivity of silicon-based materials is relatively low, and the diffusion rate of lithium in silicon is relatively low, which is not conducive to the transmission of lithium ions and electrons; Aiming at the problem of poor cycle stability caused by the volume expansion of elemental silicon, the main solutions at present are nanocrystallization and recombination, and the practical application is mainly to improve its conductivity and lithium ion transport by doping carbon materials or designing and modifying the structural end of silicon materials.
In this paper, the morphology, electronic conductivity, compaction density and compressive properties of silicon-carbon materials with different doping ratios and silicon-based materials with different sintering processes were systematically tested and analyzed by using scanning electron microscope, powder conductivity and compaction density testing equipment.