Layered Lithium Metal Composite Oxide for Battery Capacity Balance
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Solution Overview
Problem
Lithium metal composite oxides with a layered structure used in batteries tend to exhibit increased discharge capacity at high temperatures, leading to capacity imbalance between the positive and negative electrodes, which accelerates battery deterioration, especially in in-vehicle batteries.
Innovation Solution
A lithium metal composite oxide with a specific layered structure expressed by General Formula Li1+x(MnαCoβNiγ)1−xO2, where 0.00≤X≤0.07, 0.10≤α≤0.40, 0.10≤β≤0.40, and 0.30≤γ≤0.75, having a specific surface area of 2.0 to 5.0 m2/g and a ratio of average particle size to crystallite size between 5.7 and 18.5, is developed to suppress the increase in discharge capacity at high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If lithium metal composite oxide with layered structure is used as positive electrode active material, then charge and discharge capacity and lithium ion diffusibility are improved, but discharge capacity increases excessively at high temperatures causing capacity imbalance
Solution Approach 1:
The patent applies parameter changes by precisely controlling the stoichiometric ratios of transition metals (Ni: 0.30≤γ≤0.75, Mn: 0.10≤α≤0.40, Co: 0.10≤β≤0.40) and lithium excess (0.00≤x≤0.07) in the Li1+x(MnαCoβNiγ)1−xO2 structure. This compositional parameter optimization suppresses high-temperature discharge capacity increase while maintaining adequate charge-discharge capacity, thereby resolving the capacity balance issue between electrodes.
Solution Approach 2:
The patent employs composite materials by creating a multi-element transition metal oxide system (Mn-Ni-Co-Li) with a layered structure. The synergistic combination of different transition metals provides both high capacity performance and suppressed high-temperature capacity increase, achieving capacity balance while maintaining productivity.
2Use of energy by moving object
If lithium metal composite oxide with layered structure is used, then energy density is improved, but battery deterioration accelerates due to capacity imbalance
Solution Approach 1:
The patent optimizes the compositional parameters of the lithium metal composite oxide, specifically controlling the lithium excess parameter x (0.00≤x≤0.07) and transition metal ratios, to achieve a balance between energy density and battery life. The controlled composition suppresses high-temperature capacity increase that leads to capacity imbalance, thereby extending battery life while maintaining high energy density.
Solution Approach 2:
The patent uses a composite lithium transition metal oxide system (Li-Mn-Ni-Co-O) with a layered structure that combines the benefits of multiple elements. This composite material provides high energy density through the layered structure while the specific composition ratios suppress deterioration, thereby extending battery life.
3Productivity
If high nickel content is used to increase capacity, then charge and discharge capacity is improved, but high-temperature capacity increase and deterioration are accelerated
Solution Approach 1:
The patent applies parameter changes by optimizing the nickel content parameter (0.30≤γ≤0.75) in combination with manganese (0.10≤α≤0.40) and cobalt (0.10≤β≤0.40) content, along with controlled lithium excess (0.00≤x≤0.07). This multi-parameter optimization maintains adequate charge-discharge capacity while suppressing the harmful effect of excessive high-temperature capacity increase that would otherwise accelerate deterioration.
Solution Approach 2:
The patent uses a composite material system where nickel is combined with manganese and cobalt in specific ratios within a layered lithium transition metal oxide structure. This composite approach allows the material to maintain the high capacity benefits of nickel while the presence of other elements and the layered structure suppress high-temperature capacity increase and associated deterioration.
Data Source
AI summary
Provided is a lithium metal composite oxide having a layered structure, which is particularly excellent as a positive electrode active material for batteries that are mounted on electric vehicles or hybrid vehicles. Proposed is a lithium metal composite oxide having a layered structure, which is represented by general formula Li1+x(MnαCoβNiγ)1−xO2 (0.00≤X≤0.07, 0.10≤α≤0.40, 0.10≤β≤0.40, and 0.30≤γ≤0.75) and has a specific surface area of more than 2.0 m2/g but 5.0 m2/g or less and has an average particle size of the primary particles/crystallite size ratio of 5.7 to 18.5.