As an important component of lithium ion battery, negative electrode material has a direct impact on the energy density, cycle life and safety performance of the battery and other key indicators. Silicon is the anode material of lithium ion battery with the highest specific capacity (4200mAh/g) known at present. However, due to its over 300% volume effect, The silicon electrode material will pulverize during charging and discharging, and flake off from the collector fluid. caused the loss of electrical contact between active matter and active matter, the active matter, and the stream of fluid, and forming a new layer of solid electrolyte layers, which ultimately leads to the deterioration of electrochemical properties. In order to solve this problem, researchers have made a lot of explorations and attempts, among which silicon-carbon composites are very promising materials.
Carbon material, as the cathode material of lithium ion battery, has a small volume change in the charging and discharging process, and has good cycling stability and excellent conductivity, so it is often used to compound with silicon. Among the carbon-silicon composite cathode materials, according to the types of carbon materials, they can be divided into two categories: The combination of silicon and traditional carbon materials and silicon and new materials, The traditional carbon materials mainly include graphite, intermediate phase microspheres, carbon black and amorphous carbon. New carbon materials mainly include carbon nanotubes, carbon nanowires, carbon gels and graphene. Silicon carbon composite is adopted to restrain and buffer the volume expansion of silicon active center by utilizing the porous effect of carbon material, prevent particle agglomeration, prevent electrolyte from penetrating into the center, and maintain the stability of interface and SEI film.
Many enterprises around the world have begun to work on this new type of cathode material, silicon carbon new cathode material as the direction of future product research and development.