Surface-Modified Cathode Material for High-Voltage Lithium Batteries
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Solution Overview
Problem
Lithium-containing composite oxides used in non-aqueous electrolyte secondary batteries, such as lithium secondary batteries, face challenges in achieving high discharge capacity, cyclic charge and discharge properties, and safety, especially at high operating voltages, due to insufficient aluminum content in the surface layer.
Innovation Solution
A cathode active material with surface-modified lithium-containing composite oxide particles, where aluminum is present in a high concentration in the surface layer, enhancing the discharge capacity and cyclic charge and discharge properties, and maintaining safety even at high operating voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If lithium nickel composite oxide is used as cathode active material, then high capacity is achieved, but thermal stability is low and safety is reduced
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the inner core region contains lithium nickel composite oxide for high capacity, while the outer shell region contains lithium nickel manganese cobalt composite oxide for thermal stability. This spatial differentiation allows each region to perform its specialized function, resolving the contradiction between capacity and safety.
Solution Approach 2:
The patent uses composite materials by combining lithium nickel composite oxide and lithium nickel manganese cobalt composite oxide in a core-shell configuration. The composite structure integrates the high capacity characteristics of nickel-based materials with the thermal stability of manganese-based materials, achieving both improved capacity and enhanced safety simultaneously.
2Reliability
If lithium manganese composite oxide with spinel structure is used, then thermal stability and safety are improved, but capacity is reduced
Solution Approach 1:
The patent applies local quality by positioning lithium manganese composite oxide in the outer shell region where it provides thermal stability and safety protection, while the inner core region with lithium nickel composite oxide delivers high capacity. This spatial arrangement allows the manganese-based material to fulfill its safety function without limiting the nickel-based material's capacity contribution.
Solution Approach 2:
The patent uses composite materials by integrating lithium manganese composite oxide with lithium nickel composite oxide in a core-shell structure. The composite design allows the manganese-based component to enhance thermal stability while the nickel-based component maintains high capacity, achieving synergistic performance improvement.
3Adaptability or versatility
If lithium nickel manganese cobalt composite oxide is used, then drawbacks of single element use are compensated, but none succeeded in satisfying all properties including discharge capacity, cyclic charge and discharge properties, and thermal stability
Solution Approach 1:
The patent applies local quality by creating distinct functional zones within the cathode material: the inner core optimized for capacity with lithium nickel composite oxide, and the outer shell optimized for stability with lithium nickel manganese cobalt composite oxide. This zonal approach allows each region to specialize in specific properties, achieving superior overall performance that homogeneous composite materials cannot attain.
Solution Approach 2:
The patent uses composite materials by combining lithium nickel composite oxide and lithium nickel manganese cobalt composite oxide in a core-shell configuration. This composite structure leverages the advantages of both material systems, achieving high capacity from the nickel-based core while the nickel manganese cobalt shell provides enhanced cyclic stability and thermal safety that neither material alone can deliver.
4Quantity of substance
If charging voltage is increased to 4.5 V to improve discharge capacity, then utilization rate of cathode active material increases, but cyclic charge and discharge properties are insufficient
Solution Approach 1:
The patent applies local quality by creating a protective outer shell of lithium nickel manganese cobalt composite oxide that stabilizes the cathode material during high-voltage charging cycles. This shell structure protects the inner high-capacity core from degradation mechanisms that normally occur at 4.5 V, enabling the material to maintain both high capacity utilization and excellent cyclic stability.
Solution Approach 2:
The patent uses composite materials by combining lithium nickel composite oxide and lithium nickel manganese cobalt composite oxide in a core-shell configuration. This composite structure enables the cathode to operate at 4.5 V with high capacity utilization while the nickel manganese cobalt shell provides structural stability that maintains cyclic charge and discharge properties, overcoming the limitations of single-phase materials at high voltage.
Data Source
AI summary
Provided are a cathode active material with high safety, with high discharge capacity even at high operating voltage, and with excellent cyclic charge and discharge properties, its production method and a non-aqueous electrolyte secondary battery containing the cathode active material.The cathode active material for a non-aqueous electrolyte secondary battery comprises a surface-modified lithium-containing composite oxide particle, wherein the particle is a lithium-containing composite oxide particle represented by the general formula LipNxO2 (wherein N═NiyM1-y-zLz, M contains at least one element selected from Co and Mn, L is an element selected from alkaline earth metal elements, aluminum and transition metal elements other than Ni, Co and Mn, 0.9≦p≦1.1, 0.9≦x<1.1, 0.2≦y≦0.9, and 0≦z≦0.3), and a surface layer of the particle contains aluminum, said surface layer within 5 nm having an aluminum content of at least 0.8 as an atomic ratio to a total of Ni and the element M.