Core-Shell Precursor for Lithium Battery Cathode
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Solution Overview
Problem
Current lithium secondary battery positive electrode active materials face challenges with thermal stability, capacity, and output characteristics, particularly due to issues with lithium-containing cobalt oxide, lithium manganese oxides, and nickel-based materials, which suffer from high temperature safety concerns, resource limitations, and chemical instability.
Innovation Solution
A precursor for a positive electrode active material is developed with a core-shell structure, where the core is composed of nickel-rich transition metal oxides and the shell of cobalt-rich lithium transition metal oxides, both incorporating anions other than hydroxyl groups to enhance density and stability, and zirconium is used to improve structural stability by substituting transition metals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lithium-containing cobalt oxide (LiCoO2) is used as positive electrode active material, then charge/discharge efficiency and lifespan characteristics are improved, but high temperature safety is lowered and material cost increases
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the core region contains nickel-rich transition metal oxides for high capacity and the shell region contains cobalt-rich lithium transition metal oxides for thermal stability. This spatial differentiation allows each region to optimize its local properties - the core provides capacity while the shell provides safety - resolving the contradiction between lifespan/capacity and thermal safety.
Solution Approach 2:
The patent uses composite materials by combining nickel-rich transition metal oxides and cobalt-rich lithium transition metal oxides in a core-shell structure. The composite nature allows the material to simultaneously exhibit high capacity characteristics from the nickel-rich core and excellent thermal stability from the cobalt-rich shell, resolving the contradiction between performance and safety.
2Object-affected harmful factors
If lithium manganese oxides (LiMnO2, LiMn2O4) are used as positive electrode active material, then thermal stability and cost are improved, but capacity and high temperature characteristics are lowered
Solution Approach 1:
The patent applies local quality by concentrating nickel-rich transition metal oxides in the core region where high capacity is needed, while placing cobalt-rich lithium transition metal oxides in the shell region for thermal stability. This allows the material to achieve both high capacity (from the nickel-rich core) and thermal stability (from the cobalt-rich shell), resolving the contradiction between capacity and thermal stability.
Solution Approach 2:
The patent uses composite materials by combining nickel-rich and cobalt-rich lithium transition metal oxides in a core-shell structure. The nickel-rich core provides high capacity while the cobalt-rich shell provides thermal stability, allowing the composite material to simultaneously achieve properties that neither component could provide alone, resolving the contradiction between capacity and thermal stability.
3Quantity of substance
If nickel-based positive electrode active material (LiNiO2) is used, then cost and discharging capacity are improved, but crystal structure stability is lowered and chemical stability in air/moisture is reduced
Solution Approach 1:
The patent applies local quality by placing nickel-rich transition metal oxides in the core region where high discharging capacity is needed, while surrounding it with a shell of cobalt-rich lithium transition metal oxides that provide crystal structure stability and chemical stability. This spatial arrangement allows the nickel-rich core to maximize capacity while the stable shell protects the overall structure, resolving the contradiction between capacity and stability.
Solution Approach 2:
The patent uses composite materials by combining nickel-rich transition metal oxides with cobalt-rich lithium transition metal oxides in a core-shell structure. The nickel-rich component provides high discharging capacity while the cobalt-rich component provides crystal structure stability and resistance to air/moisture, resolving the contradiction between capacity and stability.
4Reliability
If metal-substituted nickel-based lithium-transition metal oxides are used, then cycle characteristics are improved, but long-term cycle characteristics deteriorate and thermal stability is reduced
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the core contains nickel-rich transition metal oxides with metal substitution for good cycle characteristics, while the shell contains cobalt-rich lithium transition metal oxides for thermal stability. This allows the core to provide excellent cycle characteristics while the shell maintains thermal stability, resolving the contradiction between cycle characteristics and thermal stability.
Solution Approach 2:
The patent uses composite materials by combining nickel-rich transition metal oxides (with metal substitution for cycle characteristics) and cobalt-rich lithium transition metal oxides (for thermal stability) in a core-shell structure. The composite structure allows simultaneous achievement of good cycle characteristics from the nickel-rich core and thermal stability from the cobalt-rich shell, resolving the contradiction between cycle characteristics and thermal stability.
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 resulting positive electrode active material exhibits improved thermal stability, high capacity, and excellent high-output characteristics, increasing battery lifespan and production yield while maintaining structural integrity.
Implementation Method 1
zirconium is used to improve structural stability by substituting transition metals
Data Source
AI summary
The present invention provides a precursor for the production of a positive electrode active material for a secondary battery comprising: a core composed of transition metal hydroxides including nickel(Ni) and manganese(Mn) and further including anions other than hydroxyl groups(OH), or transition metal hydroxides including nickel(Ni), manganese(Mn) and cobalt(Co) and further including anions other than hydroxyl groups(OH); and a shell composed of transition metal hydroxides including cobalt(Co) and further including anions other than hydroxyl groups(OH), and a positive electrode active material for lithium secondary battery produced using the same.