Lithium metal negative electrode, preparation thereof and application of lithium metal negative electrode

Abstract

The invention relates to a lithium metal negative electrode, a preparation thereof and application of the lithium metal negative electrode. According to the lithium metal negative electrode, lithium metal is taken as a substrate; the surface, facing a positive electrode, of the substrate is sequentially coated with a solid lithium salt layer and a polymer electrolyte layer. When the lithium metalnegative electrode is applied to a lithium metal battery, an electrolyte system in which lithium ion concentration from a positive electrode to the negative electrode is in low-to-high gradient distribution can be formed. With the electrolyte with lithium ions in gradient distribution adopted, the problems of low ionic conductivity and high interface contact impedance in a solid electrolyte can beeffectively solved, and the problem of poor stability of an SEI film in a liquid electrolyte can be also solved; lithium dendritic crystal growth can be inhibited; and the cycling stability of a lithium battery can be improved. The electrolyte has important practical application value.

Description

technical field [0001] The invention relates to the field of lithium metal batteries and belongs to the field of batteries. Background technique [0002] With the rapid development of the economy, people consume more and more energy, and the non-renewable resources are decreasing day by day, which makes the field of batteries get more and more attention. Among the existing batteries, lithium-ion batteries are the most researched. Although the energy density of lithium-ion batteries is higher than that of lead-acid and nickel-metal hydride batteries, it still cannot meet people's needs for higher energy densities. Therefore, researchers will focus on research transferred to lithium metal secondary batteries. The high specific capacity (3860mAh / g) and low reduction potential (-3.04V vs SHE) of lithium metal make it the most promising anode material for lithium metal secondary batteries. In metal lithium secondary batteries, the lithium anode is the main factor affecting the ...

AI Technical Summary

Problems solved by technology

First, the lithium dendrite problem, that is, the growth of lithium dendrites during the charge-discharge cycle of the battery can cause internal short circuits and serious safety issues in the battery, and it can also cause repeated damage to the SEI film to cause reactions between metal lithium and the electrolyte.

Second, the cycle efficiency is low. There are two reasons: the repeated damage and repair of the SEI film on the surface of lithium metal during charging and discharging, which consumes lithium metal and shortens the battery life; the generation of irreversible "dead lithium" will also reduce the lithium metal battery capacity

However, the SEI film spontaneously formed by lithium anode and electrolyte has poor mechanical strength and slow ion transport rate, which cannot effectively inhibit dendrite growth, and is prone to structural rupture and regeneration, resulting in a decrease in battery Coulombic efficiency and cycle life.

In addition, the use of solid electrolytes also has a series of problems such as low room temperature ionic conductivity and large interface impedance, which are difficult to meet the application requirements of lithium metal batteries.

Images