Gradient Cathode Material for Lithium Battery Thermal Stability
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Solution Overview
Problem
Current cathode materials for lithium batteries face challenges such as high cost, toxicity, and thermal instability, particularly due to the use of cobalt, which limits their capacity and thermal stability, and existing methods for improving these issues have not been satisfactory.
Innovation Solution
A cathode active material with a concentration gradient of metals like nickel, cobalt, and manganese, combined with additional elements such as aluminum or titanium, is developed, where the composition changes from the center to the outer shell, enhancing structural stability and capacitance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cobalt is used in cathode material to achieve stable charge/discharge characteristics and high battery voltage, then electrochemical performance is improved, but cost increases and toxicity problems occur
Solution Approach 1:
The patent applies local quality by creating a concentration gradient where cobalt content varies spatially within the cathode material particle. The inner core region contains higher cobalt content for stable electrochemical performance, while the outer shell region contains lower cobalt content to reduce toxicity and cost. This non-uniform distribution allows different regions to serve different functions, resolving the contradiction between performance and harmful factors.
Solution Approach 2:
The patent uses composite materials by combining multiple metal elements (nickel, cobalt, manganese, and other transition metals) in a gradient distribution within the cathode structure. This composite approach allows the material to exhibit both the electrochemical stability of cobalt-rich regions and the reduced toxicity/cost of cobalt-poor regions, simultaneously achieving multiple conflicting requirements.
2Quantity of substance
If nickel content is increased to achieve high capacitance in cathode active material, then capacity is improved, but thermal stability deteriorates and risk of battery burning increases
Solution Approach 1:
The patent applies local quality by creating a spatial gradient of metal composition where nickel concentration varies from the inner core to the outer shell. The inner core maintains higher nickel content for high capacitance, while the outer shell has reduced nickel content and increased stable metal content (such as manganese or aluminum) to provide thermal stability. This local differentiation resolves the contradiction between capacity and thermal stability.
Solution Approach 2:
The patent uses beforehand cushioning by incorporating thermally stable metals in the outer shell region before thermal runaway can occur. This outer shell acts as a protective barrier that suppresses exothermic reactions and prevents electrolyte decomposition, cushioning against thermal instability before it can propagate to the high-nickel core region.
3Temperature
If transition metal elements are used to replace nickel to improve thermal stability, then heat generation temperature shifts higher, but charge/discharge characteristics and cycle life deteriorate
Solution Approach 1:
The patent applies local quality by strategically distributing different metal elements in different spatial regions. The inner core contains nickel-rich composition for superior charge/discharge characteristics and cycle life, while the outer shell contains transition metal elements (such as manganese, aluminum, or other stable metals) that provide thermal stability and shift heat generation to higher temperatures. This spatial separation allows each region to optimize for its specific function without compromising the other.
Solution Approach 2:
The patent uses composite materials by creating a gradient structure that combines nickel-based compounds (for electrochemical performance) with transition metal compounds (for thermal stability). This composite approach allows the cathode material to simultaneously exhibit both high-capacity charge/discharge characteristics from the nickel core and enhanced thermal stability from the transition metal shell, resolving the contradiction between these two properties.
Data Source
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AI summary
The present disclosure relates to a cathode active material for lithium battery and a method of manufacturing the same, and more specifically relates to a cathode active material for manufacturing lithium battery which is doped by different metal and has gradient concentration and a method of manufacturing the same.