A composite polymer three-dimensional structure metal lithium electrode and lithium ion battery

Abstract

The invention provides a metal lithium electrode with a composite polymer three-dimensional structure, which is characterized in that it includes a polymer film, an electronic conductive material, an ion conductive material and metal lithium, and the electronic conductive material and ions are doped in the polymer film. As a conductive material, the polymer film has a porous structure, and the pores of the polymer film are filled with the metal lithium. The metal lithium electrode with a composite polymer three-dimensional structure provided by the present invention can be directly used as a negative electrode, which can effectively avoid the problem of dead lithium; even after the formation of dead lithium, it can bypass the collapsed shell structure of the negative electrode material for ion conduction; phase Compared with traditional negative electrodes, it is smaller in size and lighter in weight, which can greatly improve the volume specific energy density and mass specific energy density of the battery. In addition, it can also be used as a lithium-replenishing material for the negative electrode to uniformly replenish lithium and improve the first-cycle charge-discharge efficiency of the battery.

Description

technical field [0001] The invention relates to the technical field of batteries, in particular to a metal lithium electrode with a composite polymer three-dimensional structure and a lithium ion battery. Background technique [0002] Compared with other secondary batteries, lithium-ion batteries have the advantages of high voltage, high energy density, long cycle life and good safety performance, and become the most widely used rechargeable batteries, such as portable electronic products, electric vehicles and other large mobile devices. Power Battery. At present, the mature battery negative electrode materials are mainly graphite materials. After years of development, its energy density has been developed to a level close to the theoretical value (theoretical specific capacity is 372mAh / g), which limits the further improvement of the battery energy density and cannot meet the needs of the future. Batteries require high energy density. [0003] Compared with graphite-base...

AI Technical Summary

Problems solved by technology

However, the uneven deposition of lithium metal in the lithium metal negative electrode during the charging and discharging process will lead to the generation of a large number of lithium dendrites, which will pierce the battery separator, cause a short circuit of the battery, and generate a lot of heat, causing accidents such as fire or even explosion.

In addition, the growth of lithium dendrites also makes it difficult to form a stable solid electrolyte interface (SEI) film on the electrode surface, resulting in the consumption of a large amount of lithium. Low Coulombic efficiency and fast capacity decay

In addition, the metal lithium negative electrode has electrode volume expansion during the cycle, which is easy to cause problems such as internal pressure changes and interface fluctuations.

[0004] In order to solve the lithium dendrite problem in the lithium metal negative electrode, the surface properties of the lithium metal negative electrode are modified by using electrolyte additives in the prior art; Capacity loss, increased internal resistance, and poor electrochemical performance cannot fundamentally solve the problems of dendrite growth, low Coulombic efficiency, and poor battery cycle performance caused by metal lithium electrodes.

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