Three-dimensional composite metal lithium negative electrode, metal lithium battery and device

Abstract

The invention relates to a three-dimensional composite metal lithium negative electrode, a metal lithium battery and a device. The composite metal lithium negative electrode comprises metal lithium particles and a three-dimensional polymer skeleton, the metal lithium particles are loaded in the three-dimensional polymer skeleton, and the three-dimensional polymer skeleton comprises a lithium-loving fragment, an active site and a polymer-containing part. The volume effect of the metal lithium negative electrode in the charging and discharging process is improved, and the side reaction of the metal lithium and the electrolyte can be inhibited; the specific surface area of the metal lithium negative electrode is increased, and lithium-loving nano-sites are introduced, so that the metal lithium can be guided to be uniformly deposited, and the growth of lithium dendrites can be effectively inhibited; in addition, the three-dimensional framework is coated with active lithium, so that the risk that an SEI film is relatively brittle in a traditional scheme can be effectively inhibited.

Description

technical field [0001] The present application relates to the field of electrochemistry, in particular to a three-dimensional composite lithium metal negative electrode, a lithium metal battery and a device. Background technique [0002] Today, portable electronic devices, electric vehicles, and large power grids have higher and higher demands on battery energy density. However, the currently used lithium-ion batteries mostly use graphite as the negative electrode material. After recent years of development, it has approached its theoretical energy density. It is difficult to further increase the battery energy density. Since metal lithium has a very high theoretical specific capacity (3860mAh / g) and the lowest reduction potential (-3.04Vvs. standard hydrogen electrode) as the negative electrode, it is considered to be the most potential negative electrode material for the next generation of lithium batteries. [0003] However, the existing metal lithium negative electrode ...

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Problems solved by technology

[0003] However, the existing metal lithium negative electrode and metal lithium battery system mainly have the following problems: 1) During the deposition and dissolution process of metal lithium, when the apparent current density is large, the microscopic current density distribution on the surface of metal lithium is uneven, making lithium Uneven deposition leads to the generation of lithium dendrites, further short-circuiting the battery and causing safety problems; 2) Lithium metal is chemically active and easily reacts with the electrolyte, thereby consuming the electrolyte; 3) The volume effect is serious during the process of lithium deposition and dissolution

[0004] Therefore, researchers have proposed the following solutions to solve the above problems, such as 1) decomposing and constructing SEI films on the surface of metal lithium by additives, solvents or suitable lithium salts, but in general, the constructed SEI films are relatively brittle, and the volume changes It is easy to break during the process, thus exposing fresh lithium, and the SEI film components are mostly LiF, Li 2 CO 3 , LiOH and RCO 2 - Li and other substances, the conductivity of lithium ions is very low; 2) By designing a three-dimensional current collector, the specific surface area of ​​the negative electrode is increased to reduce the microscopic current density, but usually this method needs to supplement metal lithium to the three-dimensional current collector by melting , and did not take into account the protection of metal lithium, resulting in faster electrolyte consumption; 3) using a solid electrolyte, but the interface resistance between the solid electrolyte and the positive and negative electrodes is high, and the conductivity of lithium ions is poor, and high current charging and discharging cannot be realized

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