Silicon-based negative binder and preparation method thereof

Abstract

The invention provides a silicon-based negative binder which is an amphiphilic block copolymer modified by fluorinated organic acid, and the block copolymer is obtained by the reaction of two different polymers prepared in advance. The binder can effectively suppress the expansion of the silicon-based negative electrode, so that the silicon negative battery exhibits good cycle performance. The preparation method has the advantages of simple synthesis method, simple process and suitability for industrial production.

Description

technical field [0001] The invention belongs to the field of battery materials, and relates to a negative electrode binder, in particular to a silicon-based negative electrode binder and a preparation method thereof. Background technique [0002] With the rise of new energy vehicles, power batteries have become a key component of new energy vehicles, and power batteries have become an area that OEMs focus on and even deploy. Compared with traditional fuel vehicles, electric vehicles are more environmentally friendly and have received strong support from the state. The Ministry of Industry and Information Technology and the National Development and Reform Commission issued a notice stating that by 2020, the specific energy of a single power battery must reach 300wh / kg, and to achieve such a high energy density, The traditional graphite negative electrode is powerless. At present, a more realistic solution is to use silicon-based negative electrodes. In comparison, the theoret...

AI Technical Summary

Problems solved by technology

[0003] The advantages of using a silicon-based negative electrode are obvious. However, in the actual application process, the most important defect is: during the recharge-discharge cycle of the silicon-based negative electrode, the volume continues to expand, up to 300%, causing the active material of the negative electrode to rupture and differentiate. In contact with the electrolyte, the SEI is constantly broken and reconstructed, consuming a large amount of electrolyte, the impedance becomes larger, and the cycle performance does not break, which eventually leads to battery failure

However, the double cross-linked binder of this technical solution has poor expansion inhibition on the silicon-based negative electrode, and there are problems in safety.