Cathode Active Material Crystal Ratios for Stable High-Power Batteries
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Solution Overview
Problem
Lithium metal oxides used as cathode active materials in lithium secondary batteries face issues with uniformity, thermal and mechanical stability, leading to degraded life-span properties and operational reliability, especially when designed for high power compositions.
Innovation Solution
A cathode active material with a specific crystallite size ratio of (003) to (110) and (104) planes, ranging from 0.7 to 2.0 and 0.7 to 1.7 respectively, is developed, maintaining crystal structure stability and controlling lithium ion migration, using a lithium transition metal oxide with high nickel content and potentially manganese, and incorporating sulfur to enhance stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If lithium metal oxide is designed to have high power composition, then power and capacity are improved, but uniformity, thermal and mechanical stability of particles deteriorate
Solution Approach 1:
The patent applies parameter changes by precisely controlling the crystallite size ratios of different crystal planes ((003)/(110) and (003)/(104) ratios between 0.7-2.0). This parameter control enables the material to achieve high power and capacity while maintaining particle stability, directly resolving the contradiction between power enhancement and stability deterioration
Solution Approach 2:
The patent uses composite material strategy by creating a lithium transition metal oxide with specific crystalline structure characteristics. The controlled crystallite size ratio creates a composite-like structure that combines high power properties with enhanced stability, preventing particle degradation while maintaining high performance
2Quantity of substance
If high power composition is designed, then capacity increases, but life-span properties and operational reliability degrade
Solution Approach 1:
The patent changes the structural parameters by controlling crystallite size ratios to maintain structural integrity during charge-discharge cycles. This enables high capacity operation while preserving reliability and life-span properties through sustained structural stability
Solution Approach 2:
The patent applies beforehand cushioning by pre-establishing a stable crystalline structure with controlled crystallite size ratios before operation. This pre-optimized structure acts as a cushion against degradation during high-power operation, maintaining reliability and life-span properties even under demanding conditions
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 structural stability and lithium ion mobility, maintaining high capacity and power while preventing cracks and resistance increase, even under high-temperature conditions.
Implementation Method 1
a ratio of a crystallite size of a (003) plane to a crystallite size of a (110) plane measured by an X-ray diffraction (XRD) analysis is in a range from 0.7 to 2.0
Data Source
AI summary
A cathode active material for a lithium secondary battery has a structure of a lithium transition metal oxide. A ratio of a crystallite size of a (003) plane to a crystallite size of a (110) plane measured by an X-ray diffraction (XRD) analysis is in a range from 0.7 to 2.0, and a ratio of the crystallite size of the (003) plane to a crystallite size of a (104) plane measured by the XRD analysis is in a range from 0.7 to 2.0. A cathode for a lithium secondary battery and a lithium secondary battery include the cathode active material for a lithium secondary battery.