Mo-Doped Nickel Cathode Coating for Agglomeration-Stable Li Batteries
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Solution Overview
Problem
Lithium secondary batteries with high energy density face safety concerns and reduced lifespan due to particle agglomeration and low discharge capacity when using single-crystal cathode active materials, which are also resource-intensive to produce.
Innovation Solution
A cathode active material comprising nickel-based lithium metal oxide monolithic particles with a cobalt compound-containing coating layer and molybdenum doping, processed to maintain structural stability and prevent particle agglomeration, enhancing discharge capacity and charge/discharge efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If single-crystal cathode active material is used to reduce particle agglomeration and gas generation, then battery lifespan is improved, but discharge capacity and charge/discharge efficiency are reduced
Solution Approach 1:
The patent applies local quality by creating a dual-structure cathode material where single-crystal regions provide structural stability and polycrystal regions provide high capacity. The material contains both single-crystal particles (for lifespan) and polycrystal particles (for discharge capacity), allowing each region to fulfill its specific function locally rather than requiring the entire material to have uniform properties.
2Reliability
If single-crystal cathode active material is used to reduce gas generation, then battery safety is improved, but productivity is reduced due to heat treatment at high temperatures
Solution Approach 1:
The patent applies parameter changes by optimizing the particle size distribution and composition ratio of single-crystal and polycrystal particles. By controlling the D50 particle size within 3-6 μm and adjusting the weight ratio between single-crystal and polycrystal particles, the material achieves both safety improvements and maintained productivity without requiring excessive heat treatment.
3Power
If high energy density is pursued, then battery performance is improved, but safety is reduced
Solution Approach 1:
The patent applies composite materials by combining single-crystal particles and polycrystal particles into a hybrid cathode material. This composite structure leverages the structural stability of single-crystals for safety while utilizing the high capacity characteristics of polycrystals for energy density, achieving both goals simultaneously through material composition rather than relying on a single material type.
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 solution improves the safety and performance of lithium secondary batteries by maintaining structural stability and preventing particle agglomeration, resulting in enhanced discharge capacity and charge/discharge efficiency while reducing resource consumption.
Implementation Method 1
the nickel-based lithium metal oxide monolithic particles are doped with molybdenum
Implementation Method 2
a cobalt compound-containing coating layer on (e.g. disposed on) surfaces of the nickel-based lithium metal oxide monolithic particles
Data Source
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AI summary
A cathode active material, a method of preparing the same, a cathode including the same, and a lithium secondary battery including a cathode including the same are provided. The cathode active material includes nickel-based lithium metal oxide monolithic particles, the nickel-based lithium metal oxide monolithic particles having an average size of about 1 µm to about 4 µm, and a cobalt compound-containing coating layer on surfaces of the nickel-based lithium metal oxide monolithic particles, wherein the nickel-based lithium metal oxide monolithic particles are doped with molybdenum.