Core-Shell Cathode Lithium Additive for Stable Li-Ion Supplementation
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Solution Overview
Problem
Current lithium-supplementing materials for cathodes in lithium-ion batteries face challenges such as low electronic and ionic conductivity, poor storage stability, and limited capacity, leading to inefficient lithium deintercalation and irreversible capacity loss during the charging process.
Innovation Solution
A core-shell cathode lithium-supplementing additive is developed, comprising a lithium-supplementing material coated with an isolating conductive packaging layer, which enhances ion and electron conductivity, stability, and storage performance by forming a conductive carbon layer on the surface of lithium-containing particles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If lithium-supplementing materials such as LiF are used in cathodes, then lithium content is high and storage stability is improved, but electronic conductivity and ion conductivity remain low, and electrochemical decomposition potential exceeds cathode cut-off voltage
Solution Approach 1:
The patent uses composite lithium-supplementing materials combining LiF with conductive materials (such as carbon coatings or metal nanoparticles) to simultaneously achieve high storage stability and improved electronic conductivity. The composite structure allows LiF to provide lithium content and stability while the conductive additive enhances electron transport and lowers decomposition potential.
Solution Approach 2:
The patent modifies the chemical composition and physical structure of lithium-supplementing materials by adjusting LiF particle size, coating thickness, and composite ratios to optimize both storage stability and electrochemical performance. Surface modification techniques change the interface properties to improve ion conductivity while maintaining bulk stability.
2Quantity of substance
If conventional lithium-supplementing materials are used, then lithium content is high, but purity is low and interface lacks passivation layer, causing reaction with moisture to re-form LiOH
Solution Approach 1:
The patent applies thin film coatings (such as carbon layers or oxide shells) on lithium-supplementing material particles to create a protective passivation layer. This shell structure prevents direct contact between the lithium-containing core and environmental moisture, blocking the reformation of LiOH while maintaining high lithium content in the core.
Solution Approach 2:
The patent introduces intermediate protective layers between the lithium-supplementing material and the environment. These intermediary coatings act as barriers that prevent harmful reactions with moisture and oxygen, thereby stabilizing the interface while preserving the high lithium content of the underlying material.
3Reliability
If larger amount of lithium supplementing additives is used to overcome limited irreversible specific gram capacity, then capacity is improved, but proportion of cathode active material decreases, indirectly lowering energy density
Solution Approach 1:
The patent optimizes the particle size, morphology, and composition of lithium-supplementing additives to maximize their irreversible specific gram capacity. By changing these parameters, each unit of additive provides more lithium supplementation, reducing the total amount needed and preserving more cathode active material for energy storage.
Solution Approach 2:
The patent develops high-performance composite lithium-supplementing additives with enhanced capacity per unit mass. These advanced composites provide stronger lithium supplementation effects at lower loadings, thereby maintaining higher proportions of cathode active material and preserving energy density.
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 core-shell structure improves the first cycle efficiency and overall electrochemical performance of lithium-ion batteries by ensuring stable lithium supplementation, maintaining sufficient lithium ions, and extending cycle life while reducing internal resistance.
Implementation Method 1
the surface of the particles containing the lithium-supplementing material is coated with a conductive carbon layer to form a core-shell cathode lithium-supplementing additive
Implementation Method 2
a core body and a coating layer covering the core body, the coating layer is an isolating conductive packaging layer
Data Source
AI summary
A core-shell cathode lithium-supplementing additive, a preparation method therefor, and an application thereof. The core-shell cathode lithium-supplementing additive of the present application comprises a core body and a coating layer covering the core body, the coating layer being an isolating conductive packaging layer, the core body containing a lithium-supplementing material, and the lithium-supplementing material comprising Li2+cAcB1−c and/or LiaXb, wherein 0≤c≤1, A is at least one of N and P, B is at least one of S and O, 1≤a≤3, 1≤b≤3, and X is any one selected from F, S, N, B, P, O, and Se. The lithium-supplementing material contained in the core-shell cathode lithium-supplementing additive of the present application is rich in lithium, thereby increasing the Coulombic efficiency and improving the overall electrochemical performance of a battery.