Manganese Composite Cathode for High-Temperature Li-Ion Cycling
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Solution Overview
Problem
Lithium-ion batteries experience significant performance degradation under high temperatures, affecting their charge-and-discharge cycle performance and storage capabilities.
Innovation Solution
An electrochemical device with a positive electrode containing a manganese-containing composite material, specifically optimized with lithium manganese oxide and lithium nickel cobalt manganese oxide, and an electrolytic solution with controlled peak intensities and particle size distributions, enhancing high-temperature performance while maintaining cost competitiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional lithium-ion battery materials are used, then the battery achieves basic energy storage function, but the charge-and-discharge cycle performance degrades significantly under high temperatures
Solution Approach 1:
The patent uses a composite cathode material consisting of lithium nickel cobalt manganese oxide (NCM) and lithium manganese oxide (LMO) in a specific ratio. The NCM provides high specific energy and voltage, while LMO contributes to thermal stability and structural integrity at high temperatures. This composite structure resolves the contradiction by combining materials with complementary properties to maintain cycle performance under thermal stress.
Solution Approach 2:
The patent applies local quality by creating a core-shell structure where the NCM forms the core for high energy density and the LMO forms the shell for thermal stability. The specific diffraction peak intensity ratio (0.01≤B/A≤0.55) indicates optimized local crystal structure distribution that enhances high-temperature stability while maintaining electrochemical activity.
2Reliability
If high-performance materials are used to improve high-temperature performance, then the charge-and-discharge cycle performance improves, but the production cost increases
Solution Approach 1:
The patent optimizes the composition parameters by controlling the mass percentage of NCM (0.5% to 35%) and LMO (50% to 92%), along with doping element content (0.1% to 2.5%). The specific diffraction peak intensity ratio (B/A) serves as a critical parameter control metric. These parameter optimizations achieve high-temperature performance while balancing production costs by avoiding excessive use of expensive NCM material.
Solution Approach 2:
The patent incorporates cheaper LMO material as the primary component (50% to 92% mass percentage) to reduce production costs, while using a small amount of expensive NCM (0.5% to 35%) as a performance-enhancing additive. This approach achieves acceptable high-temperature performance at lower cost compared to using pure high-performance NCM cathodes.
3Reliability
If the positive active material composition is optimized for high-temperature performance, then the high-temperature storage performance improves, but the low-temperature kinetic performance may deteriorate
Solution Approach 1:
The patent carefully adjusts the composition parameters including NCM content (0.5% to 35%), LMO content (50% to 92%), and doping element content (0.1% to 2.5%). The specific diffraction peak intensity ratio (B/A between 0.01 to 0.55) and peak area ratio (I2/I1 between 0.1 to 0.5) serve as critical control parameters. These optimized parameters ensure sufficient ionic conductivity at low temperatures while maintaining high-temperature storage stability through the LMO component's structural stability.
Data Source
AI summary
An electrochemical device, including a positive electrode, a negative electrode, and an electrolytic solution. A positive active material includes a manganese-containing composite material. A lithium manganese oxide characteristic peak (400) as a first diffraction peak and a lithium nickel cobalt manganese oxide characteristic peak (104) as a second diffraction peak are included in a range of 40° to 46° in an XRD diffraction pattern of the positive active material under a condition of 30% SOC to 40% SOC. A 2θ angle of the first diffraction peak is smaller than a 2θ angle of the second diffraction peak. A peak intensity of the first diffraction peak is A, a peak intensity of the second diffraction peak is B, and satisfying: 0.01≤B/A≤0.55, thereby enhancing the high-temperature cycle performance and storage performance of the electrochemical device, and improving the low-temperature cycle performance of the electrochemical device.