An alkali metal-based negative electrode and a preparation method and application thereof

Abstract

The invention discloses an alkali metal-based negative electrode and a preparation method and application thereof. The alkali metal-based negative electrode comprises an alkali metal and a fluorocarbon material uniformly distributed in the alkali metal. The present invention introduces a fluorocarbon material into an alkali metal, alkali metal fluoride can be formed in situ during the charge and discharge process, a synergistic effect is formed between the fluoride and the carbon material, and a uniform electric field is formed during the charging and discharging process, thereby promoting theuniform deposition of the alkali metal, effectively inhibiting the formation of the alkali metal dendrite and the interface reaction between the alkali metal and the electrolyte, and improving the safety performance and cycle stability of the alkali metal battery.

Description

technical field [0001] The invention relates to the technical field of energy storage batteries, in particular to an alkali metal-based negative electrode and its preparation method and application. Background technique [0002] Although lithium-ion batteries still occupy a dominant position in secondary batteries, as new energy vehicles require higher and higher energy density of lithium-ion batteries, the energy density of traditional lithium-ion batteries based on intercalation reactions has reached the limit, namely The energy density of lithium-ion batteries with graphite as the negative electrode is close to the bottleneck value, and it is imperative to develop lithium batteries with metallic lithium as the negative electrode (including lithium-sulfur batteries and lithium-air batteries). On the other hand, with the development of new energy vehicles, the consumption of lithium resources is rapid, but the reserves of lithium on the earth are very limited. In contrast, ...

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Problems solved by technology

[0004] Previous studies have focused on the protection of alkali metals by carbon materials and fluorides. For example, the Chinese patent document with the publication number CN 108063218A discloses a method for preparing a thin-layer metal lithium-based negative electrode. The negative electrode has a copper foil current collector as the substrate. A single-layer graphene film is synthesized on the surface of a copper foil current collector by chemical vapor deposition. The graphene supported by the copper foil is used as the negative electrode, and the lithium-rich material or lithium salt is used as the positive electrode to form a lithium battery, and then the current is applied to make the lithium-rich The lithium in the material or lithium salt is deposited in the graphene supported by copper foil to obtain a metal lithium / graphene composite negative electrode. Although a relatively uniform composite negative electrode can be obtained by this method, it is suitable for a relatively thin electrode, but when the electrode is thicker In addition, although the carbon material has a better effect on inhibiting lithium dendrites, it is less effective in protecting the electrode and inhibiting the reaction with the electrolyte.

[0005] Another example is that the Chinese patent literature with the authorized publication number CN 207441857U discloses a lithium metal / artificial inorganic salt composite electrode, which is obtained after depositing inorganic substances on the surface of lithium metal by magnetron sputtering. The inorganic substances are as follows: Lithium fluoride, lithium bromide, lithium chloride, etc. Although this method can obtain a relatively uniform surface coating layer, it is also only suitable for thin electrodes, and it is not easy to achieve large-scale preparation. In addition, due to the low conductivity of inorganic substances, The introduction of simple inorganic compounds will cause a decrease in the conductivity of the electrode

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