Novel silicon-containing negative electrode and lithium ion battery

Abstract

The invention is applicable to the technical field of silicon-carbon negative electrodes, and provides a novel silicon-containing negative electrode which comprises a first low-silicon layer, a second low-silicon layer and a third low-silicon layer, a high silicon layer; a second low silicon layer; and a negative electrode active material; according to the heterogeneous interlayer electrode provided by the invention, negative effects on the electrode caused by expansion and contraction of silicon particles are avoided, and the second low-silicon layer increases contact sites between the active material and the current collector and improves the compaction density at the same time, so that the electron conduction performance between the active material layer and the current collector is enhanced; the high-silicon layer provides a buffer space for volume expansion of silicon particles and improves the electrolyte retaining amount of the pole piece, and the first low-silicon layer is beneficial to relieving diffusion of transition metal ions into the pole piece and relieving the promotion effect of the transition metal ions on continuous thickening of an SEI film; and the relatively low silicon content ratio also reduces the damage of the expansion effect to the outer layer structure of the electrode and the SEI film, and reduces the capacity fading induced by the side reaction of the electrolyte and the transition metal ions.

Description

technical field [0001] The invention belongs to the technical field of silicon-carbon negative electrodes, and in particular relates to a novel silicon-containing negative electrode and a lithium-ion battery. Background technique [0002] In view of the resource crisis and environmental impact of traditional fuels, the development and promotion of new energy vehicles has become the consensus of the world today. As the heart of current new energy vehicles, lithium-ion power batteries have undergone long-term development, and have also demonstrated advantages such as high energy density and long cycle life that are different from traditional lead-acid and nickel-metal hydride batteries. However, compared with traditional fuel vehicles, electric vehicles still have certain disadvantages in terms of battery life. The main reason is that the current commercial power battery chemical system is still dominated by lithium iron phosphate / graphite or ternary / graphite, and the energy ...

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Problems solved by technology

[0005] The purpose of the embodiments of the present invention is to provide a new silicon-containing negative electrode and lithium-ion battery, aiming to solve the problem that the expansion and shrinkage of silicon particles in the existing silicon-containing negative electrode and lithium-ion battery will have a negative effect on the electrode, which is not conducive to battery performance.

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