Single-Crystal Nickel Cathode Suppresses Aggregation
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Solution Overview
Problem
Lithium secondary batteries with high energy density suffer from safety concerns and exhibit particle aggregation, decreased productivity, and increased residual lithium during the manufacturing of single-crystal cathode active materials, leading to reduced capacity and efficiency.
Innovation Solution
A nickel-based metal oxide with a cubic composite phase, comprising a rock salt cubic phase and an ordered rock salt cubic phase, is developed, which is heat-treated to create a single-crystal nickel-based active material with a high nickel content, suppressing particle aggregation and residual lithium without the need for washing, thereby improving battery lifespan and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If single-crystal cathode active materials are used to improve lifespan characteristics, then battery lifespan is improved, but particle aggregation occurs and productivity decreases
Solution Approach 1:
The invention segments the cathode active material into hierarchical structures with primary particles (5-20 μm) aggregated into secondary particles (50-200 μm). This segmentation allows the material to maintain single-crystal characteristics for lifespan improvement while the controlled aggregation prevents excessive particle coagulation that would reduce productivity.
2Duration of action of stationary object
If single-crystal cathode active materials are used to improve lifespan characteristics, then battery lifespan is improved, but residual lithium increases and capacity decreases
Solution Approach 1:
The invention applies local quality control by creating a core-shell structure where the inner core consists of single-crystal particles with controlled composition, and the outer shell has different characteristics. This allows the single-crystal core to provide lifespan improvement while the shell structure prevents excessive residual lithium formation and maintains capacity.
3Use of energy by moving object
If high energy density is achieved using lithium nickel manganese cobalt composite oxide, then energy density is improved, but safety deteriorates
Solution Approach 1:
The invention uses composite materials by combining lithium nickel manganese cobalt composite oxide with lithium cobalt oxide in a controlled ratio (70:30 to 95:5). This composite structure maintains high energy density from the nickel-based material while the lithium cobalt oxide component improves safety and structural stability.
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 nickel-based active material enhances the lifespan and charge/discharge efficiency of lithium secondary batteries by reducing gas generation and maintaining a stable crystal structure during charging and discharging, while minimizing residual lithium and improving productivity.
Implementation Method 1
A nickel-based metal oxide with a cubic composite phase, comprising a rock salt cubic phase and an ordered rock salt cubic phase, is developed, which is heat-treated to create a single-crystal nickel-based active material
Data Source
AI summary
A nickel-based metal oxide for a lithium secondary battery, a nickel-based active material obtained from the nickel-based lithium metal oxide, a method of preparing the nickel-based metal oxide, and a lithium secondary battery including the nickel-based metal oxide as a cathode are provided. The nickel-based metal oxide for a lithium secondary battery is a single-crystal particle and includes a cubic composite phase, wherein the cubic composite phase includes a metal oxide phase represented by Formula 1 and a metal oxide phase represented by Formula 2:Ni1-x-z-kMkLixCozO1-y, Formula 1wherein, in Formula 1, 0≤x≤0.1, 0≤y≤0.1, 0≤z≤0.5, and 0≤k≤0.5,Ni6-x-z-kMkLixCozMnO8-y, and Formula 2wherein, in Formula 2, 0≤x≤0.1, 0≤y≤0.1, 0≤z≤0.5, and 0≤k≤0.5, and the case where x of Formula 1 and x of Formula 2 are 0 at the same time is excluded.