Preparation Of Silicon-carbon Composite Material For Ion Battery Anode Material

Preparation of silicon-carbon composite material for ion battery anode material

Lithium-ion batteries (LIB) have been increasingly used in large-capacity storage devices such as electric vehicles and energy storage devices (ESS) and mobile devices due to their stable life characteristics and high efficiency.

The following strategies can be used to advance the energy density of the LIB (Wh = kg): 1) modify the electrode data 2) improve the coating technology 3) improve the data filling in the anode and cathode, 4) advance the lithium absorption rate of the cathode. However, methods 2-4 are generally limited to optimizing internal space and planning, and therefore, research into the composition of new electrode materials is being actively conducted.

Currently, the most representative source of cathodes used in LIBS is graphite. Because of the uniaxial orientation of the graphene layer, it exhibits a highly reversible charge-discharge behavior and therefore has a long cycle life.

In addition, when graphite is completely charged, that is, when lithium ions are present between the layers, the electrode potential is 0V vs Li = Li +. This indicates that graphite can exhibit a potential similar to that of pure Li metal. Therefore, higher energy can be obtained by assembling a battery with a graphite cathode and an oxide-based anode.

However, considering the demand for high-capacity batteries at that time, the low theoretical capacity of graphite (372mAh = g, 837mAh = cm3) is a key obstacle to the continuous use of graphite as anode material. Therefore, in order to develop high-capacity, high-performance lithium secondary batteries, it is important to develop non-carbon anode materials.

Among these non-carbon materials, Si is the most suitable because it has a high discharge capacity of 4200mAh = g and a lithium response potential of 0.4V (vsLi = Li +). However, Si encountered a key problem, that is, the volume changes severely during the charge and discharge process, resulting in poor reversibility and sensitive capacity decay.

Numerous approaches have been proposed to reduce volume expansion, such as the nano-scale response of metal particles to lithium, the composition of heterogeneous alloys that react with lithium, and active = inactive metal complexes and lithium alloy = carbon composition. 11-15)

In this workshop, we attempt to deal with the bulk expansion problem in silicon by compose silicon-carbon black (Si-CB) composite data. The CB structure is formed by the aggregation of primary particles in different directions to form a network of different directions and spaces formed in the CB aggregate due to random growth. 16-19)

Therefore, in the case of volume expansion, these spaces will be used as a buffer to contain silicon