Lithium ion battery waterborne silicon-based negative pole piece and preparation method thereof

Abstract

The invention discloses a lithium ion battery waterborne silicon-based negative pole piece and a preparation method thereof. The negative pole piece comprises a battery negative pole current collector and a silicon-based negative pole. A conductive coating is arranged between the battery negative pole current collector and the silicon-based negative pole. The conductive coating is prepared from, by mass, 5-40% of butadiene styrene rubber emulsion, 1-15% of carboxymethyl cellulose, 10-90% of conductive carbon black and 20-80% of solvent, and the total mass percentage of the raw materials is 100%. The coating is arranged between copper foil and the silicon-based negative pole of the waterborne silicon-based negative pole piece, the silicon-based negative pole piece does not influence deintercalation of active substances, namely lithium ions, by designing a brand new coating formula and optimizing the preparation process, contact of the active substances and the current collector is prevented, stripping of the negative pole piece and the current collector after pole piece expansion of the silicon-based negative pole in the battery charging and discharging process is relieved, and accordingly the problems that electrical contact is lost, capacity is quickly attenuated due to relieving and circulation performance deteriorates are solved.

Description

technical field [0001] The invention relates to a lithium-ion battery water-based silicon-based negative electrode sheet and a preparation method thereof, belonging to the technical field of lithium-ion batteries. Background technique [0002] At present, the global lithium battery anode materials are still dominated by natural graphite and artificial graphite, accounting for more than 80% in 2015. The output of new materials such as silicon carbon (Si / C) anode materials is also growing rapidly, and the rapid development of portable and mobile electronic devices has greatly stimulated the market demand for lithium-ion batteries with light weight, small capacity and higher energy density. At present, commercial lithium-ion batteries use carbon-based materials as negative electrodes, but the reversible capacity of graphite negative electrodes is only 372mAh / g (LiC6), which seriously limits the development of lithium-ion batteries in the future, so the development of next-gener...

AI Technical Summary

Problems solved by technology

However, the disadvantages of this material are also very prominent: the volume of the material will expand during the lithium intercalation and delithiation process, and the lithium intercalation and delithiation reaction of silicon will be accompanied by a large volume change (~300%), resulting in the destruction of the material structure and mechanical powder. This leads to the separation between the electrode materials and the electrode material and the current collector, and then the loss of electrical contact, resulting in rapid capacity decay and deterioration of cycle performance

Images