W/B-Doped Cathode Active Material for High-Nickel Cycle-Life Stability
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Solution Overview
Problem
Lithium secondary batteries face issues with high production costs of positive electrode active materials, elution of components during charging and discharging, and degradation due to electrolyte decomposition, especially when high nickel compositions are used, leading to safety and capacity deterioration.
Innovation Solution
A positive electrode active material for lithium secondary batteries is developed, composed of secondary particles with primary particles having a rough surface, doped with tungsten (W) and boron (B), which suppresses grain growth and reduces internal porosity, enhancing cycle-life and discharge capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high nickel composition is used to achieve high capacity, then capacity is improved, but safety and output characteristics are deteriorated and capacity deterioration proceeds quickly
Solution Approach 1:
The patent applies parameter changes by precisely controlling the nickel content within 0.80-0.95 and systematically adjusting doping element concentrations (cobalt: 0.05-0.30, manganese: 0.05-0.30, aluminum: 0.01-0.10) to optimize the balance between capacity and cycle-life characteristics, transforming the high nickel composition from a problematic state to an optimized state with improved reliability
Solution Approach 2:
The patent creates a composite cathode material structure by combining multiple elements (nickel, cobalt, manganese, aluminum) in specific ratios within the NCM system, where each element contributes different properties: nickel provides capacity, cobalt enhances stability, manganese improves safety, and aluminum strengthens the crystal structure, achieving synergistic effects that resolve the contradiction between high capacity and long cycle-life
2Ease of manufacture
If positive electrode active material production cost is reduced, then manufacturing cost is improved, but capacity deterioration and resistance increase due to electrolyte decomposition are worsened
Solution Approach 1:
The patent changes the compositional parameters by replacing expensive cobalt-rich formulations with optimized nickel-dominant compositions supplemented with cheaper manganese and aluminum, achieving cost reduction while maintaining or improving performance through systematic parameter optimization of element ratios and doping concentrations
Solution Approach 2:
The patent substitutes expensive long-lived cobalt materials with more economical manganese and aluminum doping strategies, using cost-effective doping elements to achieve the desired performance characteristics, thereby reducing production costs while preventing capacity deterioration and resistance increase through proper material selection
Data Source
AI summary
It is related to a positive electrode active material for lithium secondary battery, and to a lithium secondary battery containing the same. To improve the battery characteristics of high-capacity positive electrode materials by simultaneously doping tungsten (W) element, which has an excellent effect on electrical conductivity, and boron (B) element, which is positioned on the surface to suppress the negative reaction of residual lithium and electrolyte solution.