Lithium Manganate Cathode Material for High-Temperature Battery Stability
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Solution Overview
Problem
Current lithium manganate materials for non-aqueous electrolyte secondary batteries fail to achieve satisfactory high-temperature storage characteristics and output characteristics, despite efforts to improve crystallinity and particle size distribution.
Innovation Solution
Lithium manganate particles with a specific chemical composition (Li1+xMn2-x-yYO4) and uniform dispersion of Al, Mg, or Co within the particles, optimized through controlled calcination and surface treatment, exhibit improved high-temperature stability and output characteristics by adjusting intensity ratios and lattice constants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If lithium manganate particles are used as positive electrode active substance, then high voltage and high energy density are achieved, but charge/discharge cycle characteristics deteriorate due to crystal lattice expansion and contraction
Solution Approach 1:
The patent applies parameter changes by controlling particle size (1-10 μm average diameter) and crystal structure parameters (spinel structure with specific lattice constant) to optimize both energy density and cycle stability. The specific particle size range and crystalline structure parameters are tuned to reduce lattice expansion/contraction while maintaining high capacity.
Solution Approach 2:
The patent uses composite materials by incorporating aluminum compounds (such as Al2O3, Al(OH)3, or aluminum-containing hydrogencarbonate) into the lithium manganate particles. This composite structure strengthens the crystal lattice, suppresses Mn dissolution in electrolyte, and maintains structural integrity during charge/discharge cycles, thereby improving cycle characteristics while preserving high energy density.
2Reliability
If different kinds of elements are added to lithium manganate particles to strengthen bonding force, then charge/discharge cycle characteristics improve, but manufacturing complexity increases
Solution Approach 1:
The patent uses aluminum compounds as intermediary substances that facilitate the strengthening of the lithium manganate crystal lattice. The aluminum-containing compounds act as a mediating agent during the firing process, forming a stable composite structure that improves cycle characteristics without requiring complex multi-step manufacturing processes.
Solution Approach 2:
The patent optimizes manufacturing by controlling specific parameters: aluminum compound content (0.1-5 wt%), particle size (1-10 μm), and firing temperature (900-1100°C). These parameter specifications simplify the manufacturing process by providing clear targets rather than requiring complex process control, thereby improving reliability without excessively increasing manufacturing complexity.
3Reliability
If surface treatment is applied to lithium manganate particles to suppress Mn elution, then charge/discharge cycle characteristics improve, but production cost increases
Solution Approach 1:
The patent merges the surface treatment function with the particle formation process itself. By incorporating aluminum compounds during the firing process rather than applying a separate surface coating step, the patent achieves Mn elution suppression while avoiding the additional production costs and complexity of separate surface treatment operations.
Solution Approach 2:
The lithium manganate particles perform self-protection against Mn dissolution through the in-situ formation of aluminum-containing compounds during firing. The aluminum compounds are incorporated during the synthesis process, allowing the material to self-protect against elution without requiring external surface treatment, thereby reducing production costs while improving cycle characteristics.
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 resulting lithium manganate particles demonstrate enhanced high-temperature stability and output characteristics, suitable for non-aqueous electrolyte secondary batteries, with improved charge/discharge cycle performance and capacity retention.
Implementation Method 1
mixing a manganese compound and a lithium compound at a predetermined ratio and then calcining the resulting mixture at a temperature of 700 to 800°C
Implementation Method 2
when charge/discharge cycles are repeated, the crystal lattice is expanded and contracted owing to desorption and insertion behavior of lithium ions in the crystal structure to cause change in volume of the crystal
Data Source
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AI summary
The present invention aims at providing lithium manganate having a high output and an excellent high-temperature stability. The above aim can be achieved by lithium manganate particles having a primary particle diameter of not less than 1 µm and an average particle diameter (D50) of kinetic particles of not less than 1 µm and not more than 10 µm, which are substantially in the form of single crystal particles and have a composition represented by the following chemical formula: Li1+xMn2-x-yYyO4 in which Y is at least one element selected from the group consisting of Al, Mg and Co; x and y satisfy 0.03 ≤ x ≤ 0.15 and 0.05 ≤ y ≤ 0.20, respectively, wherein the Y element is uniformly dispersed within the respective particles, and an intensity ratio of I(400)/I(111) thereof is not less than 33% and an intensity ratio of I(440)/I(111) thereof is not less than 16%.