Core-Shell Nickel Hydroxide Cathode for Capacity and Thermal Stability
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Solution Overview
Problem
Existing lithium-metal composite oxides and their precursors exhibit limited charge and discharge capacity, thermal stability, and weather resistance, necessitating improvements for higher energy density and safety in secondary batteries.
Innovation Solution
A lithium-metal composite oxide with a core-shell structure and controlled particle size distribution is developed, featuring different Ni ratios on the particle surface and inside, along with a specific production method involving two crystallization processes to form a core and shell portion, enhancing thermal stability and weather resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If lithium-nickel composite oxide is used to increase charge and discharge capacity, then battery capacity is improved, but thermal stability deteriorates
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the inner core contains high-nickel content (0.6 ≤ x1 < 0.8) for high capacity, while the outer shell has lower nickel content (0.2 ≤ x2 < 0.4) for thermal stability. This spatial differentiation of composition allows each region to perform its specialized function: the core provides capacity while the shell provides stability.
Solution Approach 2:
The patent uses composite materials by combining nickel-rich and nickel-poor phases into a single core-shell structured composite. The inner core region (Ni1-x1-y1Cox1Mny1(OH)2) and outer shell region (Ni1-x2-y2Cox2Mnym2(OH)2) form a composite structure that integrates the high-capacity properties of nickel-rich materials with the thermal-stability properties of nickel-poor materials.
2Quantity of substance
If particle size distribution is widened to improve filling property and energy density, then energy density is improved, but manufacturing precision deteriorates
Solution Approach 1:
The patent applies parameter changes by controlling the particle size distribution within a specific range (0.6 ≤ D90/D10 < 1.4) rather than using a wide distribution. This controlled parameter range achieves good filling property (tap density ≥ 2.0 g/cm³) while maintaining manufacturing precision and compositional uniformity throughout the particle size range.
3Quantity of substance
If nickel content is increased to enhance capacity, then charge and discharge capacity is improved, but weather resistance deteriorates
Solution Approach 1:
The patent applies local quality by concentrating high nickel content (x1 ≥ 0.6) in the inner core region where it contributes to capacity without direct exposure to environmental factors. The outer shell region has lower nickel content (x2 < 0.4) and acts as a protective layer that resists weathering, moisture, and atmospheric degradation, thus improving overall weather resistance while maintaining high capacity.
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 structured lithium-metal composite oxide achieves high charge and discharge capacity, thermal stability, and weather resistance, facilitating easy industrial-scale production of positive electrode active materials for secondary batteries.
Implementation Method 1
a first crystallization process of supplying a first raw material aqueous solution containing nickel and at least one of cobalt, manganese, or the element M, adjusting a pH value of a reaction aqueous solution to 11.5 or more and 13.5 or less at a liquid temperature of 25° C., and performing crystallization to form the core portion
Implementation Method 2
adjusting a pH value of a reaction aqueous solution to 11.5 or more and 13.5 or less at a liquid temperature of 25° C., and performing crystallization to form the core portion
Data Source
AI summary
A metal composite hydroxide represented by a general formula (1): Ni1-x-yCoxMnyMz(OH)2+α (where 0.02≤x≤0.3, 0.02≤y≤0.3, 0≤z≤0.05, and −0.5≤α≤0.5 are satisfied and M is at least one element selected from the group consisting of Mg, Ca, Al, Si, Fe, Cr, V, Mo, W, Nb, Ti, and Zr), in which the metal composite hydroxide contains a first particle having a core portion inside the particle and a shell portion formed around the core portion and [(D90−D10)/MV] is 0.80 or more.