A kind of solid lithium battery, composite negative electrode and preparation method thereof

Abstract

The invention discloses a solid-state lithium battery composite negative electrode, which comprises a negative electrode current collector, a negative electrode elastic-plastic body and a negative electrode lithium metal which are sequentially stacked and connected, wherein the negative electrode elastic-plastic body takes a three-dimensional space structure coated with an organic polymer as a container, the interior of the container is provided with an island-bridge three-dimensional interlaced porous structure which takes an active material lithium titanate and the like as an island and takes an electric conduction and heat conduction material carbon black and the like as a bridge, the negative electrode elastic-plastic body is tightly bonded with the current collector and the lithium metal, and the lithium metal is embedded into the dried negative electrode elastic-plastic body through hot pressing to form a composite negative electrode with a layered structure. The invention also discloses a solid-state battery adopting the composite negative electrode, and a preparation method of the solid-state battery, wherein a three-dimensional porous disordered island-bridge frame structure of a negative electrode material is constructed through a negative electrode elastic-plastic body, so that the mechanical strength of the negative electrode material is improved, the volume changeof the negative electrode material during charging and discharging is absorbed and buffered, the growth of lithium dendrites is inhibited, the overall performance of the solid-state battery is improved, and the manufacturing cost is reduced.

Description

technical field [0001] The invention belongs to the technical field of secondary lithium battery manufacturing, and in particular relates to a solid lithium battery for manufacturing power batteries and other products, a composite negative electrode and a preparation method thereof. Background technique [0002] At present, liquid lithium-ion batteries have been well applied in the consumer field, new energy vehicles and other transportation fields, as well as energy storage, base stations and other energy fields. Although liquid electrolyte lithium-ion battery cells adopt a variety of measures to meet the safety requirements of most applications, there are still safety risks of thermal runaway, overheating, fire and even explosion. [0003] All-solid-state lithium-ion batteries use solid-state electrolytes instead of traditional organic liquid electrolytes, which can avoid continuous side reactions in liquid electrolytes, improve battery safety issues, and are expected to f...

AI Technical Summary

Problems solved by technology

However, the porous copper foil is expensive, and the negative electrode interface bonding strength after thermal compounding with lithium metal is poor, and the overall mechanical strength is poor, which will reduce the cycle life of lithium batteries; at the same time, the high temperature thermal compounding of lithium metal sheets requires high equipment. The process is complex, especially it still cannot avoid the problem of interfacial lithium dendrite growth

[0010] In summary, although using lithium metal as the negative electrode of lithium-ion batteries has natural advantages, metal lithium negative electrodes are also considered by the industry to be the ultimate negative electrode solution for high-energy-density batteries. However, the use of copper foil to prepare high-performance current collectors and tabs The composite material and industrialization process of metal lithium / copper negative electrode foil are also one of the key restrictive technologies for solid-state lithium-ion batteries

Poor mechanical strength is the biggest defect of metal lithium / copper anode foil

The poor bonding force between the lithium metal negative electrode and the copper foil layer may easily lead to power failure of the lithium metal during the working process of the battery, making it impossible to achieve large-scale production and application

In the solid-state lithium battery manufacturing industry, there are still problems such as high cost, complicated process, and short service life of the product. It is urgent to develop high-performance, low-cost electrode materials, and stable, reliable, and easy-to-industrial preparation processes.

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