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Lithium-ion batteries show great potential in more demanding applications such as electric vehicles. As the negative electrode of lithium-ion batteries, graphite has a specific capacity limit of 372 mAh/g for energy storage, which is difficult to meet the demand for high capacity. The specific capacity of silicon-based materials used in lithium-ion batteries is 10 times that of graphite. But silicon itself also has many problems such as poor conductivity. With graphene's high conductivity and super large specific surface area, we can make graphene-based carbon-silicon composite materials with high-quality properties to overcome the problem of silicon series materials in lithium batteries.
Among various anode materials, silicon has attracted much attention because of its highest theoretical specific capacity (about 4200 mAh/g). The practical application of Si anodes is currently hindered by many challenges. The main reason is the huge volume change (about 300%) during complete lithiation, and the expansion/contraction stress generated during the lithiation/delithiation process, which leads to serious Si cracking. Studies have shown that graphene can effectively buffer the volume change of silicon.
Figure 1. Graphene paper buffering the volume change of Si and providing a conductive network during cycling. (Chang J, et al. 2014)
Graphene-based silicon-carbon composites have shown great potential as anode materials for lithium-ion batteries due to their high capacity, good operating potential, environmental friendliness and high abundance. They can perfectly improve the problems existing in silicon anodes, such as particle crushing, shedding, and the decline of electrochemical performance during lithiation and delithiation.
Figure 2. (a) Schematic illustration of the fabrication process of multilayered Si/rGO nanostructures, (b) Multilayered Si/rGO electrode cycled at 3C for 300 cycles. (Chang J, et al. 2014)
Alfa Chemistry has many years of experience in graphene-based silicon-carbon anode compounding. It can quickly compound graphene for different silicon materials to solve corresponding problems and develop high-specific energy and high-performance silicon-carbon anode materials.
Chemical vapor deposition (CVD), physical vapor deposition (PVD), high temperature solid phase synthesis, mechanical alloying, graphene modification and other technologies.
SEM, TEM, AFM, XPS, ICP-OES, ICP-MS, EDS, Raman spectroscopy and other detection platforms.
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