Layered High-Nickel Cathode Composition With Lithium-Excess Control
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Solution Overview
Problem
Existing lithium secondary batteries face challenges with high-capacity production of layer-type lithium transition metal oxides, particularly due to the instability of Ni(III) and significant changes in electrochemical characteristics with small lithium composition variations during synthesis.
Innovation Solution
Development of lithium-excessive high nickel-based positive active materials with a layered metal oxide crystal structure, featuring a nickel content of 80 mol% or more and a specific lithium substitution amount, which enhances stability and energy density while minimizing cation mixing and impurity formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high nickel content (80 mol% or more) is used to increase capacity, then energy density is improved, but synthesis stability deteriorates due to Ni(III) instability
Solution Approach 1:
The patent changes the compositional parameters by introducing lithium substitution in the metal layer (1.5-15 mol%) and controlling the lithium-to-metal ratio (1.01-1.2), which stabilizes the high-nickel structure during synthesis and charge-discharge cycles, enabling Ni(III) stability while maintaining high capacity
Solution Approach 2:
The patent creates a composite layered structure with alternating lithium layers and metal layers containing high nickel content, where the layered architecture provides structural stability while the high nickel content delivers high capacity, resolving the contradiction between stability and quantity
2Reliability
If lithium substitution in metal layer is increased to improve stability, then synthesis stability is improved, but cation mixing increases
Solution Approach 1:
The patent optimizes the lithium substitution amount in the metal layer to a specific range (1.5-15 mol%) and controls the lithium-to-metal ratio (1.01-1.2), finding the optimal balance point where sufficient lithium substitution provides stability while excessive substitution that causes cation mixing is avoided
3Manufacturing precision
If small change in lithium composition is made during synthesis, then manufacturing precision is improved, but electrochemical characteristics change significantly
Solution Approach 1:
The patent introduces a buffered parameter system where the lithium-to-metal ratio is controlled within a specific range (1.01-1.2) and lithium substitution is maintained at 1.5-15 mol%, creating a compositional buffer that absorbs small manufacturing variations and prevents significant electrochemical characteristic changes
4Quantity of substance
If high capacity materials are produced, then energy density is improved, but stoichiometric synthesis becomes difficult
Solution Approach 1:
The patent采用非化学计量合成策略，通过控制Li/M比例在1.01-1.2范围内和锂取代量在1.5-15 mol%，实现了高容量材料的可控制备，将原本难以控制的化学计量合成转化为可控的参数优化过程
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 proposed solution achieves high price competitiveness, stability, energy density, capacity, and lifespan characteristics for lithium secondary batteries by maintaining a stable crystal structure and reducing impurity content during charge and discharge cycles.
Implementation Method 1
mixing and sintering the metal hydroxide precursor and the lithium raw material; wherein, a sintering temperature is t
Implementation Method 2
the crystal structure includes a first metal layer in which some of the metal is replaced by lithium, the crystal structure includes a first lithium layer in which some of the lithium in the lithium layer is replaced by metal
Data Source
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AI summary
It is related to a positive active material for a lithium secondary battery and a manufacturing method thereof, and is provided a positive active material which is a layered metal oxide crystal structure including a lithium layer and a metal layer, wherein, the crystal structure includes a first metal layer in which some of the metal is replaced by lithium, the crystal structure includes a first lithium layer in which some of the lithium in the lithium layer is replaced by metal, a substitution amount of lithium in the first metal layer is 1.5 mol% or more, and a nickel content is 80 mol% or more, with 100 mol% of metal in the positive active material as the reference.