Hard Carbon Anode Material Technology For Lithium Battery

Hard Carbon Anode Material Technology For Lithium Battery

Hard Carbon refers to graphitized Carbon, which is the thermal decomposition product of polymer and has a high reversible specific capacity, generally 500 ~ 700mAh/g. Hard carbon as anode material of lithium battery has stable structure, long charge-discharge cycle life and good rate performance, which can meet the requirements of high-power charging and discharging of lithium battery of electric vehicle. In addition, hard carbon is more compatible with propylene carbonate (PC) -based electrolyte than graphite.

Hard carbon surface is loose porous structure, easy to absorb water and oxygen in the air, forming a variety of C-H functional groups on the surface, lithium ions can react with these functional groups, resulting in the loss of lithium ions, improve the irreversible capacity, reduce the first efficiency. Modification of hard carbon anode material can effectively improve its electrochemical performance.

The Methods of Hard Carbon Modification Mainly Include:

1. Inorganic materials coated with hard carbon modification, doping non-metallic elements B, Si, P, N, S into the carbon material can significantly change the lithium embedding properties of hard carbon materials, reduce the irreversible capacity;

2. Chemical vapor precipitation method (CVD method) coated with hard carbon modification. At present, CVD method can keep the reversible cycle capacity at about 70% of the theoretical value. The reversible capacity of hard carbon can be further increased by optimizing the parameters of CVD method.