Phenolic-resin-modified silicon-based negative electrode material for lithium ion battery and preparation method thereof

Abstract

The invention provides a phenolic-resin-modified silicon-based negative electrode material for a lithium ion battery and a preparation method of the phenolic-resin-modified silicon-based negative electrode material. The material is prepared by modifying silicon nanoparticles by using phenolic resin and then carrying out pyrolysis. In other words, the preparation method comprises the following steps: carrying out phenolic resin crosslinking on the surfaces of silicon nanoparticles, coating the silicon nanoparticles with the crosslinked phenolic resin, and carrying out pyrolysis in an inert atmosphere to obtain a porous carbon coated nanometer silicon composite material, i.e., the phenolic resin modified silicon-based negative electrode material of the lithium ion battery. The electrical conductivity and the volume change of the porous carbon-coated nano silicon composite material in the charging and discharging process are obviously improved when being compared with that of silicon nanoparticles. Moreover, the capacity retention capability is high, and the electrochemical performance is excellent. In addition, green and low-cost phenolic resin is used as a coating material in the preparation process, the preparation method is simple, raw materials are easy to obtain, conditions are mild, batch production can be achieved, and the good industrial preparation prospect is achieved.

Description

technical field [0001] The invention relates to the technical field of negative electrode materials for lithium ion batteries, in particular to a phenolic resin-modified silicon-based negative electrode material for lithium ion batteries and a preparation method thereof. Background technique [0002] Lithium-ion batteries are widely used in portable electronic devices such as mobile phones and notebook computers. They have been initially used in electric vehicles and are expected to be used on a large scale in the future. The main goal in the development of next-generation lithium-ion batteries is to extend cycle life, increase energy density and charge-discharge specific capacity. Anode materials become the key to determine whether this goal can be achieved. [0003] Graphite is currently widely used as the negative electrode material in lithium-ion batteries, with a theoretical specific capacity of 372mAh g -1 , can no longer meet the extensive demand for large-capacity,...

AI Technical Summary

Problems solved by technology

The mechanical force generated by such a huge volume effect will gradually disengage the electrode active material from the current collector. After charging and discharging, the silicon active material phase itself will also break and pulverize, and the structure will collapse. The irreversible change of the crystalline state leads to serious damage to the structure of the electrode material, and the low conductivity of silicon leads to the generation of irreversible capacity, resulting in a rapid decline in the cycle performance of the electrode.

In addition, silicon is a semiconductor material with low intrinsic conductivity, only 6.7×10 -4 S cm -1 , the conductivity needs to be improved

[0005] Therefore, the huge volume effect and low conductivity generated during charge and discharge seriously hinder the commercial application of silicon as the anode material of lithium-ion batteries.

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