Hard carbon negative electrode material, preparation method thereof, negative pole plate and battery

Abstract

The invention belongs to the technical field of a battery, and particularly relates to a hard carbon negative electrode material. The hard carbon negative electrode material comprises a hard carbon sphere matrix, wherein oxide layers are coated at a surface functional group position and a surface defect position on the hard carbon sphere matrix. The invention also provides a preparation method ofthe hard carbon negative electrode material. The oxide layers are coated at the surface functional group position and the surface defect position on the hard carbon sphere matrix by employing an atomic layer deposition method. The invention also provides a negative pole plate. The negative pole plate comprises a negative electrode current collector, wherein a hard carbon negative material layer iscoated on a surface of the negative electrode current collector and comprises the hard carbon negative electrode material. The invention also provides the battery. The battery comprises a positive pole plate and also comprises the negative pole plate. In the hard carbon negative electrode material, the oxide layers are coated at the surface functional group position and the surface defect position of the hard carbon sphere matrix, the surface defect of hard carbon and the functional group is in contact with an organic electrolyte to generate side reaction can be prevented, and the performanceof the battery is improved.

Description

technical field [0001] The invention belongs to the technical field of batteries, and in particular relates to a hard carbon negative electrode material, a preparation method thereof, a negative electrode sheet and a battery. Background technique [0002] Hard carbon refers to carbon that is difficult to hard carbonize. It has a high reversible specific capacity, generally 500-700mAh / g; it also has the characteristics of high specific capacity, good rate performance, and excellent rate and cycle performance, as well as low temperature characteristics. As a negative electrode material for lithium-ion batteries, sodium-ion batteries and potassium-ion batteries, hard carbon has a stable structure, long charge-discharge cycle life, and good rate performance, which can meet the high-power charge-discharge requirements of lithium-ion batteries for electric vehicles. In addition, hard carbon has better compatibility with propylene carbonate (PC)-based electrolytes than graphite. ...

AI Technical Summary

Problems solved by technology

However, the coating of this type of method is uneven, and it is difficult to uniformly cover all functional groups and defects on the surface of the hard carbon, and the coated carbon layer is not dense enough, and the electrolyte can still penetrate through the coating layer to contact the hard carbon layer during charging and discharging. Carbon surface, resulting in poor cycle life and high temperature performance of the battery, severe battery gas