Composite positive electrode material, preparation method thereof and aqueous secondary battery

Abstract

The invention discloses a composite positive electrode material capable of being used for a long-cycle lithium ion battery. The composite positive electrode material comprises modified lithium manganate and modified lithium cobalt oxide, and aluminum hydroxide and neodymium oxide which coat the surfaces of the modified lithium mangnate and the modified lithium cobalt oxide. Wherein the modified lithium manganate is doped with aluminum and cobalt elements; wherein the modified lithium cobalt oxide is doped with a magnesium element. The invention also discloses a preparation method of the composite positive electrode material and an aqueous secondary battery. According to the composite positive electrode material, the composite positive electrode material is synthesized by adopting a high-temperature solid-phase method, so that double modification of material doping and coating is realized, the technological process is greatly simplified, the compaction density of an electrode plate in the battery preparation process and the cycling stability in the battery cycling process are improved, and large-scale production is facilitated.

Description

Technical field [0001] The application relates to a composite positive electrode material, a preparation method thereof and an aqueous secondary battery, belonging to the field of energy storage. Background technique [0002] Currently, the most widely used cathode material for water-based secondary batteries is lithium manganate material, but there are still major problems in electrochemical performance. Lithium manganate is considered to be the most promising cathode material for water-based batteries due to its wide range of raw materials, low price and high specific capacity. However, during charging and discharging, the manganese ions in the crystal lattice are prone to disproportionation reaction and dissolve in the aqueous solution. Therefore, it will cause serious capacity degradation during the cycle. The structure of lithium manganate changes during the charge and discharge process, the volume shrinks during the charging process, and the volume expands during the discha...

AI Technical Summary

Problems solved by technology

[0002] Lithium manganese oxide is the most widely used positive electrode material for aqueous secondary batteries, but there are still big problems in terms of electrochemical performance.

Lithium manganese oxide has the advantages of wide source of raw materials, low price, and high specific capacity, and is considered to be the most promising positive electrode material for aqueous batteries. However, during charging and discharging, manganese ions in the crystal lattice are prone to disproportionation reactions and dissolve in aqueous solutions. , so it will cause serious capacity fading during the cycle, the structure of lithium manganate will change during the charge and discharge process, the volume will shrink during the charge process, and the volume will expand during the discharge process, showing a relatively poor cycle life.

Lithium cobaltate has the advantages of simple synthesis, high specific capacity, and good cycle stability, and has a wide range of uses. However, the abundance of lithium cobaltate is low and the price is relatively expensive. It is not realistic to simply use it for large-scale water-based energy storage batteries.

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