Nickel Hydroxide Precursor Void Control for Li-Ion Cycle Stability
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Solution Overview
Problem
Lithium-ion secondary batteries face challenges in improving cycle characteristics, particularly when using lithium-nickel composite oxides, which are prone to performance degradation in high-temperature environments and have inferior cycle characteristics compared to lithium-cobalt composite oxides.
Innovation Solution
A positive electrode active material precursor for non-aqueous electrolyte secondary batteries is developed, comprising nickel composite hydroxide particles with controlled void distribution, where the area ratio of voids to the particle cross-section is less than 5.0% and specifically less than 20% in a circular region of 1.78 μm, enhancing lithium diffusion and distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If lithium-nickel composite oxide is used as positive electrode material to reduce cost, then manufacturing cost is reduced, but cycle characteristics deteriorate and battery performance is impaired in high-temperature environments
Solution Approach 1:
The invention applies local quality by creating a core-shell structure where the nickel-rich core provides high capacity and cost-effectiveness, while the cobalt-containing shell layer provides stability and protects the core from degradation. This spatial differentiation of material composition allows each region to fulfill its specific function: the core maximizes capacity and reduces cost, while the shell ensures cycle stability and high-temperature performance.
2Reliability
If lithium-cobalt composite oxide is used as positive electrode material to achieve high voltage and good cycle characteristics, then battery voltage reaches up to 4V and cycle characteristics are superior, but manufacturing cost increases significantly
Solution Approach 1:
The invention employs composite materials by combining nickel-rich and cobalt-containing phases in a core-shell structure. The nickel-rich core provides high capacity and low cost, while the cobalt-containing shell provides stability and protects the core. This composite approach allows the battery to achieve performance characteristics similar to pure cobalt systems while significantly reducing the amount of expensive cobalt required.
3Ease of manufacture
If purely nickel-based lithium-nickel composite oxide is synthesized to reduce material cost, then cost is reduced, but cycle characteristics become inferior and battery performance degrades in high-temperature environments
Solution Approach 1:
The invention applies local quality by creating a core-shell structure where the nickel-rich core provides high capacity and cost-effectiveness, while the cobalt-containing shell layer provides stability and protects the core from degradation. This spatial differentiation of material composition allows each region to fulfill its specific function: the core maximizes capacity and reduces cost, while the shell ensures cycle stability and high-temperature performance.
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 approach results in improved cycle characteristics and increased charging and discharging capacity by ensuring uniform lithium distribution within the nickel composite hydroxide particles, leading to enhanced battery performance.
Implementation Method 1
enhancing lithium diffusion and distribution
Data Source
AI summary
A positive electrode active material precursor for a non-aqueous electrolyte secondary battery, including a nickel composite hydroxide particle, is provided, wherein a cross section of the nickel composite hydroxide particle includes a void, a ratio of an area of the void to the cross section of the nickel composite hydroxide particle is less than or equal to 5.0%, a circular region having a radius of 1.78 μm is set at a position where a ratio of an area of the void to the circular region is maximum, on the cross section of the nickel composite hydroxide particle, and the ratio of the area of the void to the circular region is less than or equal to 20%.