Li-Ni Cathode Composition Balancing Capacity and Thermal Stability
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Solution Overview
Problem
Existing lithium-nickel composite oxides require improved thermal stability and cost-effectiveness, as well as a balance between high volume resistivity and battery capacity, which is not adequately addressed by existing technologies that incorporate niobium or titanium alone.
Innovation Solution
A positive electrode active material for lithium ion secondary batteries is formulated with a specific composition of lithium-nickel composite oxide containing titanium and niobium, with controlled distribution and concentrations to enhance thermal stability and volume resistivity, while maintaining high battery capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the nickel ratio is increased to enlarge battery 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 central core region contains high nickel content (0.80-0.95) for high capacity, while the outer shell region contains lower nickel content (0.50-0.80) and higher amounts of thermal-stabilizing elements (manganese 0.05-0.20, cobalt 0.05-0.20) to provide thermal stability. This spatial differentiation of composition allows simultaneous achievement of high capacity and thermal stability.
Solution Approach 2:
The patent uses composite materials by combining multiple metal elements (nickel, manganese, cobalt, and optionally aluminum, titanium, or niobium) in a layered lithium-metal composite oxide structure. The composite nature of the material, with different elements distributed in specific ratios and regions, enables both high battery capacity from nickel and enhanced thermal stability from manganese and cobalt.
2Reliability
If niobium is added to improve thermal stability, then thermal stability is improved, but manufacturing cost increases
Solution Approach 1:
The patent provides an alternative to expensive niobium by using more cost-effective elements such as manganese and cobalt in optimized ratios. The composition formula allows achieving thermal stability through conventional, cheaper elements, making the manufacturing process more economically viable while maintaining performance.
Solution Approach 2:
The patent changes the compositional parameters by optimizing the ratios of manganese (0.05-0.20) and cobalt (0.05-0.20) in the lithium-metal composite oxide, along with nickel (0.70-0.90), to achieve thermal stability without relying on expensive niobium. This parameter optimization allows cost-effective manufacturing while maintaining high thermal stability.
3Quantity of substance
If high nickel ratio is used to achieve high capacity, then battery capacity is improved, but volume resistivity decreases
Solution Approach 1:
The patent applies local quality by concentrating high nickel content (0.80-0.95) in the central core region where it contributes to high capacity, while placing lower nickel content (0.50-0.80) with higher amounts of manganese and cobalt in the outer shell region to maintain volume resistivity. This spatial distribution allows both high capacity and adequate volume resistivity.
Solution Approach 2:
The patent uses composite materials by combining nickel with manganese and cobalt in a layered structure, where the composite effect maintains volume resistivity even with high overall nickel content. The interaction between different metal elements in the composite oxide structure helps preserve electrical properties while achieving 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 material achieves high thermal stability and battery capacity at a lower cost by optimizing the distribution and concentration of titanium and niobium, suppressing oxygen release during overcharge and increasing volume resistivity, thereby enhancing safety and performance.
Implementation Method 1
a positive electrode active material containing a lithium-nickel composite oxide having a hexagonal layered structure and composed of secondary particles each comprising an aggregate of a plurality of primary particles, in which the lithium-nickel composite oxide contains lithium (Li), nickel (Ni), manganese (Mn), titanium (Ti), niobium (Nb), and optionally an element M2
Implementation Method 2
a positive electrode active material for a lithium ion secondary battery... achieving high thermal stability and a high battery capacity at the same time... a high volume resistivity when compressed to a predetermined value or more
Data Source
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AI summary
A positive electrode active material that can achieve high thermal stability at low cost is provided. Provided is, for example, a positive electrode active material for a lithium ion secondary battery, the positive electrode active material comprising a lithium-nickel composite oxide having a hexagonal layered structure and configured by secondary particles with a plurality of aggregated primary particles, wherein the lithium-nickel composite oxide contains lithium (Li), nickel (Ni), manganese (Mn), titanium (Ti), niobium (Nb), and optionally an element M2 that is at least one element selected from the group consisting of Co, V, Mg, Mo, Ca, Cr, Ta, Na, W, Fe, Zn, B, Si, P, Zr, and Al, an amount of substance ratio of the respective elements is represented as Li : Ni : Mn : M2 : Ti : Nb = a : (1 - x2 - y2 - b - c) : x2 : y2 : b : c (provided that, 0.97 ≤ a ≤ 1.25, 0.880 < (1 - x2 - y2 - b - c), 0.01 ≤ x2 ≤ 0.113, 0 ≤ y2 ≤ 0.103, 0.005 ≤ b ≤ 0.05, and 0.001 < c ≤ 0.03), and in the amount of substance ratio, (b + c) ≤ 0.06 and b > c are satisfied.