Lithium Manganese Oxide Cathode Composition for Low-Impurity Cycle Life
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Solution Overview
Problem
Conventional lithium manganese oxide cathode materials for secondary batteries suffer from high impurity levels and reduced cycle life, leading to premature capacity loss and degradation.
Innovation Solution
Development of lithium manganese oxides with a specific formula (Li1+xMn2−x−y−zMyM′zO4) and a proprietary synthesis method that minimizes trace metal impurities and incorporates nickel as a divalent transition metal, enhancing cathode material purity and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional lithium manganese oxide cathode materials are used, then manufacturing cost is reduced, but impurity levels increase and cycle life decreases
Solution Approach 1:
The patent applies parameter changes by precisely controlling the chemical composition parameters of the cathode material, specifically using the formula Li1+xMn2-x-y-zMyM′zO4 where x≤0.25, y≤0.5, and 0.1≤z≤0.7. This systematic parameter optimization allows simultaneous achievement of high purity (reduced impurities) and extended cycle life (370+ cycles), resolving the contradiction between manufacturing precision and reliability
Solution Approach 2:
The patent employs composite materials by incorporating multiple transition metals (M = Cr, Mn, Fe, Co, Ni, Cu, Zn) and divalent metals (M′ = Mn, Ni, Co, Zn) into the lithium manganese oxide structure. This composite approach creates a more stable crystal structure with enhanced purity and longevity, achieving both high manufacturing precision and superior reliability
2Reliability
If conventional cathode materials are used, then ease of manufacture is improved, but capacity retention deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-calculating and pre-mixing the exact stoichiometric ratios of multiple metal precursors according to the formula Li1+xMn2-x-y-zMyM′zO4 before synthesis. This preliminary preparation ensures that the subsequent synthesis process, while chemically complex, follows a predetermined precise recipe, achieving high capacity retention (370+ cycles) without excessive manufacturing difficulty
3Manufacturing precision
If conventional lithium manganese oxide is used, then production cost is reduced, but trace metal impurities increase
Solution Approach 1:
The patent applies the extraction principle by systematically removing harmful trace metal impurities (Al, Ca, K, Mg, Fe, Na) from the cathode material composition. By explicitly excluding these impurities and focusing on beneficial transition metals, the synthesis method achieves high purity (less than 175 ppm total trace metals) while maintaining a manageable, though enhanced, synthesis complexity
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 improved cathode material achieves a maximum capacity of at least 115 mAhr/g and extends the battery's life to at least 370 charge/discharge cycles before capacity drops below 80%, with a reduced fade rate and increased stability, outperforming conventional materials.
Implementation Method 1
An electric current passes through the electrolytic cells. During the application of current, MnO2 plates out on the anodes of the electrolytic cells.
Implementation Method 2
the method provides for conversion of MnO2 to Mn2O3 by heating
Data Source
AI summary
Disclosed herein is an improved cathode material having the general formula of Li1+xMn2−x−y−zMyM′zO4 where x is generally less than 0.25, y is less than about 0.5, z is between about 0.1 and about 0.7, M is a trivalent transition metal, M′ is a divalent transition metal. Also disclosed is an improved secondary battery having a cathode material of the general formula of Li1+xMn2−x−y−zMyM′zO4. In one embodiment, the method provides for the preparation of a solution of Mn++ ions by dissolving manganese metal, typically in the form of powder or chips, in a mineral acid. The final concentration of Mn++ in solution will be between about 20 g/L to about 254 g/L. Typically, the solution will contain about 47 g/L of Mn++. The final pH of the solution containing Mn++ may range between about two and about eight; however, a typical operational pH will be between about 5.5 and about 7.0.