Lithium Manganate Particles High-Temperature Storage
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Solution Overview
Problem
Current lithium manganate particles for non-aqueous electrolyte secondary batteries fail to exhibit satisfactory high-temperature storage characteristics due to issues with particle size, crystallinity, and reactivity with electrolyte solutions, leading to deterioration in charge/discharge cycle and high-temperature performance.
Innovation Solution
Lithium manganate particles with a spinel structure, specific particle size distribution, and incorporation of boron, produced by calcining a mixture of trimanganese tetraoxide and a lithium compound at controlled temperatures, resulting in particles with optimized pore diameters and surface area for improved stability and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If lithium manganate particles are used as positive electrode active material to achieve high voltage and high energy density, then the battery exhibits high energy density, but the charge/discharge cycle characteristics and high-temperature storage characteristics deteriorate due to crystal lattice expansion and contraction causing breakage and manganese dissolution
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the interior maintains the original lithium manganate spinel structure for high capacity, while the surface is modified with a protective coating that prevents manganese dissolution and stabilizes the crystal lattice during charge/discharge cycles. This local differentiation resolves the contradiction by protecting the high-energy-density core material from degradation at the surface.
Solution Approach 2:
The patent employs composite materials by combining lithium manganate particles with other materials that provide structural stability and prevent manganese elution. The composite structure integrates the high-capacity lithium manganate with protective matrix materials, creating a hybrid positive electrode active material that maintains both high energy density and improved cycle stability.
2Use of energy by moving object
If lithium manganate particles are used as positive electrode active material to achieve high voltage and high energy density, then the battery exhibits high energy density, but high-temperature storage characteristics deteriorate due to crystal lattice instability and manganese dissolution in electrolyte
Solution Approach 1:
The surface modification creates a localized protective environment that stabilizes the crystal lattice structure specifically at high temperatures, preventing thermal-induced degradation and manganese dissolution while maintaining the bulk material's high-capacity spinel structure for energy density.
Solution Approach 2:
The patent applies preliminary action by pre-modifying the surface of lithium manganate particles before battery assembly, creating a protective barrier that preemptively prevents high-temperature degradation and manganese dissolution during storage and operation, thereby maintaining both energy density and thermal stability.
3Manufacturing precision
If the particle size and particle size distribution of lithium manganate particles are controlled to improve packing property, then the electrode achieves better packing, but the manufacturing complexity increases due to precise size control requirements
Solution Approach 1:
The patent applies parameter changes by optimizing specific particle size ranges and size distribution parameters of lithium manganate particles to achieve optimal packing density. By carefully selecting and controlling these size parameters, the patent achieves improved electrode packing and battery energy density while maintaining a relatively simple manufacturing process through conventional particle size control methods.
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 lithium manganate particles demonstrate enhanced high-temperature storage characteristics, reduced manganese elution, and improved capacity restoration rates, making them suitable for high-energy density applications in lithium ion secondary batteries.
Implementation Method 1
calcining the resulting mixture at a temperature of 700 to 1000°C
Implementation Method 2
the lithium manganate particles having a spinel structure
Implementation Method 3
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 relates to lithium manganate particles for non-aqueous electrolyte secondary batteries, having a spinel structure, an average primary particle diameter of 0.4 to 1.8 µm and an average secondary particle diameter (D50) of 8 to 20 µm, a ratio of the average secondary particle diameter (D50) to the average primary particle diameter (D50/average primary particle diameter) being in the range of 10 to 30, and pore diameters of pores in the lithium manganate particles as measured by a mercury intrusion porosimetry method being in the range of 100 to 500 nm, and a process for producing the lithium manganate particles, and a non-aqueous electrolyte secondary battery. The lithium manganate particles according to the present invention are excellent in high-temperature storage characteristics.