Aqueous solution containing lithium and silicon, method for producing same, and method for producing active material for lithium secondary battery
By forming a lithium orthosilicate covering layer on the surface of the positive active material of the all-solid-state lithium-ion secondary battery, the problems of increased interface resistance and uneven coverage are solved, the battery performance and production efficiency are improved, and the cost is reduced.
Patent Information
- Application Number
- CN202480008836.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2023-05-19
- Filing Date
- 2024-05-13
- Publication Date
- 2025-09-12
AI Technical Summary
In existing technology, in all-solid-state lithium-ion secondary batteries, the interfacial resistance generated when lithium ions move at the interface between the positive electrode active material and the solid electrolyte increases, resulting in reduced battery capacity and battery performance. In addition, existing covering methods have problems such as low productivity, unevenness and high cost.
An aqueous solution containing lithium and silicon in a specific molar ratio is used to form a lithium orthosilicate covering layer on the surface of the positive electrode active material through drying and heat treatment to optimize lithium ion conductivity and coverage uniformity. Mechanical stirring and filtration are used to treat the particles and control the absorbance and impurity content of the aqueous solution.
Effectively reduce interface resistance, improve the performance of lithium-ion secondary batteries, ensure the uniformity of the coating and battery capacity, and reduce production costs.
Smart Images
Figure CN120641354A_ABST
Abstract
Claims
1. An aqueous solution containing lithium and silicon, comprising 0.1 mass % to 3.0 mass % of lithium and 0.1 mass % to 3.0 mass % of silicon, wherein the molar ratio of lithium to silicon (Li / Si) is 3.70 to 5.20, and the absorbance at a wavelength of 660 nm is 0.10 or less.
2. The aqueous solution containing lithium and silicon according to claim 1, wherein The aqueous solution was dried and then heat-treated at 750° C. for 5 hours in an atmosphere to obtain a calcined powder mainly composed of crystals of lithium orthosilicate Li 4 SiO 4 .
3. The aqueous solution containing lithium and silicon according to claim 1, wherein The lithium content in the aqueous solution is 0.5 mass % or more and 2.0 mass % or less.
4. The aqueous solution containing lithium and silicon according to claim 1, wherein The silicon content in the aqueous solution is 0.5 mass % or more and 2.0 mass % or less.
5. The aqueous solution containing lithium and silicon according to claim 1, wherein The molar ratio of lithium to silicon in the aqueous solution (Li / Si) is 3.70 to 5.
00.
6. The aqueous solution containing lithium and silicon according to claim 1, wherein The absorbance of the aqueous solution at a wavelength of 660 nm is less than 0.
07.
7. The method for producing an aqueous solution containing lithium and silicon according to claim 1, comprising the steps of: a step of mixing an aqueous solution containing a silicon compound and an aqueous solution containing a lithium compound to obtain an aqueous solution having a molar ratio Li / Si of lithium to silicon of 3.70 to 5.20; and A step of maintaining the aqueous solution containing lithium and silicon at 45° C. or higher and 60° C. or lower.
8. A method for producing an active material for a lithium secondary battery, wherein: The active material for lithium secondary batteries has a covering layer containing lithium orthosilicate, The manufacturing method comprises the following steps: an aqueous solution covering step, wherein the surface of the positive electrode active material of the lithium secondary battery is covered with an aqueous solution containing lithium and silicon obtained by the manufacturing method according to claim 7; a covering layer forming step of drying the lithium secondary battery positive electrode active material covered with the aqueous solution containing lithium and silicon to form a covering layer containing lithium and silicon; and The heat treatment step includes heat-treating the lithium secondary battery positive electrode active material having the coating layer containing lithium and silicon.
9. A method for producing an active material for a lithium secondary battery, wherein: The active material for lithium secondary batteries has a covering layer containing lithium orthosilicate, The manufacturing method comprises the following steps: an aqueous solution covering step, wherein the surface of the positive electrode active material of the lithium secondary battery is covered with the aqueous solution containing lithium and silicon according to claim 1; a covering layer forming step of drying the lithium secondary battery positive electrode active material covered with the aqueous solution containing lithium and silicon to form a covering layer containing lithium and silicon; and The heat treatment step includes heat-treating the lithium secondary battery positive electrode active material having the coating layer containing lithium and silicon.
Citation Information
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