All-solid-state battery with silicon negative electrode and sulfide solid electrolyte

Abstract

The invention relates to a silicon negative electrode lithium ion battery, and discloses an all-solid-state battery with a silicon negative electrode and a sulfide solid electrolyte. The battery comprises the negative electrode, a solid electrolyte layer and a positive electrode; the negative electrode comprises a current collector and a lithium intercalated layer which is fixed to the side surface of the current collector in a laminated mode; the lithium intercalated layer is formed by pressing mixed powder comprising sulfide electrolyte powder particles and silicon-containing negative electrode powder; the content of silicon in the mixed powder is 40-53wt%; the particle sizes of the sulfide electrolyte powder particles are 10-100nm; the particle size of the silicon-containing negative powder is 10-100nm; and the porosity of the lithium intercalated layer is 15-23%. The lithium intercalated layer can adaptively adjust expansion / contraction caused in a lithium de-intercalation processof the silicon-containing negative electrode powder, so that the possibility of cracking pulverization of the lithium intercalated layer is reduced, the electric contact between a desulfurization layer and the current collector and between the desulfurization layer and the solid electrolyte layer is stable, the capacity attenuation of the high-silicon negative-electrode solid-state battery is reduced, and the cycling performance of the high-silicon negative-electrode solid-state battery is improved.

Description

technical field [0001] The invention relates to a silicon negative electrode lithium ion battery, in particular to an all-solid battery with a silicon negative electrode and a sulfide solid electrolyte. Background technique [0002] Silicon is the lithium-ion battery anode material with the highest specific capacity (4200mAh / g) discovered so far by human beings. Its anode capacity density is ten times higher than that of graphite, and it is the most potential anode material. In addition, silicon is also rich in natural Reserves (the second most abundant element in the earth's crust), no harm to the environment and low electrochemical potential. [0003] However, the current silicon, as the negative electrode material of lithium-ion batteries, is still not widely used, and there are still restrictions on commercial application. This limitation is due to the nature of silicon itself, which is mainly divided into two aspects. [0004] In the first aspect, when silicon is used...

AI Technical Summary

Problems solved by technology

However, a small amount of added silicon has a limited effect on improving the energy density of the battery. Compared with other advantageous anode materials, the advantages of high specific capacity of silicon materials have not been fully developed, which makes the commercial application of silicon anode batteries less meaningful.

[0005] The second point is that the conductivity distribution on the silicon surface is uneven. If no treatment is added, the SEI film formed on the silicon surface is uneven and porous, and the electrolyte can always touch the surface immersed in the silicon, making the SEI film grow very long. Thick, consumes a lot of lithium for lithium-ion batteries and is not good for full battery performance

In this regard, the liquid electrolyte is used in silicon negative batteries in the current technology, and the amount of electrolyte added needs to be excessive, but the excessively added electrolyte not only reduces the energy density of the battery, but also only prolongs the energy density of the battery. After battery failure time

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