Low Magnesium Composite Metal Precursor for Lithium Battery Stability
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Solution Overview
Problem
Current lithium secondary battery positive electrode active materials, such as lithium cobalt oxide or lithium nickel composite oxide, exhibit unsatisfactory capacity and lifespan characteristics, particularly at high temperatures, due to inadequate control of magnesium content, which affects the electrochemical properties and stability of the electrode.
Innovation Solution
A composite metal precursor with a controlled magnesium content of less than or equal to 0.005 wt % is used to form a positive electrode active material, specifically a lithium composite oxide, which improves the high temperature interval lifespan and capacity characteristics by optimizing the composition and processing conditions, including the use of nickel, cobalt, manganese, and other elements, and controlling the presence of fluoride and chlorine ions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If magnesium content is increased to improve electrode stability, then electrochemical stability improves, but capacity and lifespan characteristics deteriorate
Solution Approach 1:
The patent applies parameter changes by precisely controlling the magnesium content to be less than or equal to 0.005 wt% in the composite metal hydroxide precursor. This specific parameter threshold resolves the contradiction by identifying the optimal concentration point where magnesium provides sufficient electrochemical stability without causing capacity degradation or lifespan reduction.
Solution Approach 2:
The patent implements local quality by creating a composite metal hydroxide structure with specific elemental distribution, where magnesium is present at controlled low levels alongside nickel, cobalt, and manganese. This localized control of magnesium content within the composite structure allows the material to maintain stability while avoiding the harmful effects of excessive magnesium that would reduce lifespan.
2Reliability
If magnesium content is increased to improve electrode stability, then electrochemical stability improves, but capacity characteristics deteriorate
Solution Approach 1:
The patent resolves this contradiction by establishing a critical parameter threshold for magnesium content (≤0.005 wt%) in the composite metal hydroxide. This parameter optimization ensures that magnesium provides the necessary electrochemical stability while preventing capacity loss, thereby simultaneously achieving both stability and high capacity characteristics in the lithium secondary battery.
3Ease of manufacture
If conventional positive electrode active materials are used, then manufacturing simplicity is maintained, but capacity and lifespan characteristics remain unsatisfactory
Solution Approach 1:
The patent applies composite materials by formulating a composite metal hydroxide precursor containing nickel, cobalt, manganese, and controlled amounts of magnesium. This composite approach improves capacity and lifespan characteristics compared to conventional single-metal oxides, while the synthesis process remains relatively simple and compatible with existing manufacturing techniques.
Data Source
AI summary
A composite metal precursor including a composite metal hydroxide represented by Formula 1 below, wherein an amount of magnesium (Mg) in the composite metal hydroxide is less than or equal to 0.005 wt %, an electrode active material formed from the same, a positive electrode including the same, and a lithium secondary battery employing the same:(A1-x-yBxCy)(OH)2 [Formula 1]wherein in Formula 1, x, y, A, B, and C are as described in the detailed description.