Electrode for lithium battery, preparation method thereof, and lithium battery containing the electrode

Abstract

The invention relates to an electrode for a lithium battery, a preparation method thereof and a lithium battery containing the electrode, belonging to the technical field of batteries. The lithium battery electrode of the present invention includes a current collector, an electrochemically active layer disposed on the current collector, and a modification layer coated on the outer surface of the electrochemically active layer; the material of the electrochemically active layer includes In the electrode active material, the modification layer is formed of lithium ion exchange polymer. The electrode for lithium battery of the present invention adopts lithium ion exchange polymer as the modification layer to coat the electrochemically active layer, and the modification layer has better shape retention to the electrode, thereby to a certain extent suppressing material pulverization caused by volume change , and inhibit the cracking of the pole piece; at the same time, the lithium ion exchange capacity can also ensure the lithium ion transmission rate in the electrochemical process and reduce the influence of the coating on the impedance.

Description

technical field [0001] The invention relates to an electrode, a preparation method thereof, and a lithium battery containing the electrode, in particular to an electrode for a lithium battery, a preparation method thereof, and a lithium battery containing the electrode. Background technique [0002] In recent years, lithium-ion batteries have been widely used in the field of new energy vehicles. With the development of the new energy automobile industry, people have put forward higher and higher requirements for the performance of lithium-ion batteries, especially the energy density. [0003] In order to achieve the battery design and performance goals with a lithium-ion battery energy density of 300Wh / kg in 2020, it is almost inevitable to choose a lithium-ion battery chemistry system containing silicon / tin negative electrodes. Silicon / tin-based negative electrode materials have high specific capacity, but during the charging and discharging process, the huge and repeated ...

AI Technical Summary

Problems solved by technology

[0008] Most of the existing mass-produced lithium battery pole piece designs, when using silicon / tin-containing negative electrode materials, or sulfur-containing positive electrode materials, due to the large expansion / contraction of the active material during charging and discharging, repeated volume changes are easy. It causes the pole piece to crack, the material is pulverized, and further falls off from the current collector. At the same time, the SEI film will continue to thicken and consume the electrolyte, resulting in battery capacity attenuation and pole piece deactivation.

Some advanced research also adds a conductive layer or polymer layer on the active material layer, but most of them cannot take into account conformality / inhibition of volume change and sufficient lithium ion transport channels at the same time, or most of the production processes are more complicated

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