Application of high-molecular coating in aluminium negative electrode, aluminium negative electrode, preparation method thereof and secondary battery

Abstract

The invention discloses application of a high-molecular coating in an aluminium negative electrode, the aluminium negative electrode, a preparation method thereof and a secondary battery and relates to the field of electrochemical energy storage devices. For the application of the high-molecular coating in the aluminium negative electrode, the aluminium negative electrode is used as a negative current collector and a negative active material simultaneously. The aluminium negative electrode is used as the negative current collector and the negative active material simultaneously and is coated with the high-molecular coating; the secondary battery comprises the aluminium negative electrode. The application disclosed by the invention has the beneficial effects that the problems that the volume of the aluminium negative electrode used as the negative current collector and the negative active material is expanded and the capacity is attenuated due to an unstable solid electrolyte membrane are relieved; after the high-molecular coating is applied on the aluminium negative electrode, electrolytic solution and the aluminium negative electrode can be effectively isolated, the aluminium negative electrode can be prevented from being eroded and reacted, the coulombic efficiency is effectively improved, the irreversible capacity can be reduced, the cyclic stability of the battery can be improved, simultaneously certain role is played in inhibiting powdering of the aluminium negative electrode in the process of volume expansion, and the integrity of the aluminium negative electrode structure can be ensured.

Description

Technical field [0001] The invention relates to the technical field of electrochemical energy storage devices, and in particular to an application of a polymer coating in an aluminum negative electrode, an aluminum negative electrode, a preparation method thereof, and a secondary battery. Background technique [0002] Lithium-ion batteries have the advantages of high energy density, high energy efficiency, long cycle life, no memory effect, fast discharge, etc., so they have a huge market in consumer electronics and electric vehicles, grid peak shaving, energy storage power supplies, aerospace and other fields demand. In order to cope with the performance, cost and environmental challenges faced by lithium-ion batteries, the development of electrode materials with abundant reserves, cheap and easy to obtain, and excellent electrochemical performance is the current research and development direction. [0003] Traditional lithium ion battery anode materials are graphite materials. W...

AI Technical Summary

Problems solved by technology

However, there are also some problems when aluminum foil is used as the negative electrode: (1) Lithium ions experience huge volume expansion during the alloying process with aluminum metal, resulting in electrode pulverization and battery capacity attenuation; (2) metal aluminum and electrolyte react at the interface The formed solid electrolyte layer (Solid Electrolyte Interface, SEI film) thickens with time, the interface impedance continues to increase, the Coulombic efficiency decreases, and the battery capacity decays; (3) due to the continuous change in the volume of the aluminum metal negative electrode during charge and discharge, the SEI film Unstable, in the process of lithium deintercalation, continuous generation-breakage-regeneration, consumption of metal lithium and electrolyte

However, carbon is coated with an inorganic compound protective layer, which will also be broken to a certain extent during the volume expansion of the aluminum negative electrode, which cannot effectively improve the volume expansion and the capacity fading caused by the unstable solid electrolyte membrane.

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