Fluoride-Coated Cathode Material With Controlled Surface Carbonate
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Solution Overview
Problem
Batteries using positive electrode materials coated with lithium-containing fluorides experience high internal resistance due to the deterioration of the coating layer caused by alkaline components on the surface of the positive electrode active material, leading to increased resistance during charge and discharge.
Innovation Solution
A coated active material is developed with a lithium-containing fluoride coating layer on the positive electrode active material, controlling the amount of lithium hydrogen carbonate on the surface to 130-580 ppm, and using a lithium-containing fluoride composition to enhance ionic conductivity and suppress the formation of resistance layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a lithium-containing fluoride coating layer is applied to the positive electrode active material, then ionic conductivity is enhanced and resistance layer formation is suppressed, but the coating layer deteriorates due to alkaline components on the surface, leading to increased internal resistance
Solution Approach 1:
The patent applies preliminary action by controlling the amount of lithium hydrogen carbonate on the surface of the positive electrode active material before applying the lithium-containing fluoride coating layer. By pre-regulating the alkaline component content to within a specific range (130-580 ppm), the surface is prepared in advance to prevent deterioration of the coating layer during battery operation, thus maintaining low internal resistance and stable performance.
2Reliability
If the amount of lithium hydrogen carbonate on the surface is controlled to 130-580 ppm, then coating layer deterioration is prevented, but precise control and measurement of the carbonate amount is required
Solution Approach 1:
The patent applies parameter changes by establishing a specific quantitative range (130-580 ppm) for lithium hydrogen carbonate content on the surface of the positive electrode active material. This parameter control transforms the qualitative problem of preventing coating layer deterioration into a quantitative manufacturing specification, enabling precise control through measurable parameters and facilitating consistent production of stable battery performance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The coated active material reduces internal battery resistance by preventing the deterioration of the coating layer and maintaining effective ionic conductivity, thereby enhancing battery performance.
Implementation Method 1
the coating layer includes a lithium-containing fluoride... suppress the formation of resistance layers
Implementation Method 2
deterioration of the coating layer caused by alkaline components on the surface of the positive electrode active material
Data Source
AI summary
A coated active material (100) of the present disclosure includes: a positive electrode active material (11); lithium hydrogen carbonate present on a surface of the positive electrode active material (11); and a coating layer (12) coating at least a portion of the surface of the positive electrode active material (11). The coating layer (12) includes a lithium-containing fluoride. When a mass of the lithium hydrogen carbonate present on the surface of the positive electrode active material (11) is measured by thermogravimetry-mass spectrometry, a proportion R1 of the mass of the lithium hydrogen carbonate in a mass of the positive electrode active material (11) is 130 ppm or more and 580 ppm or less.