Phosphate-Modified Spinel Lithium Manganese Oxide for High-Temperature Cycling
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Solution Overview
Problem
Spinel-type lithium manganese oxide exhibits poor charge-discharge performance at high temperatures, particularly when used with carbon as a negative electrode, due to instability and manganese elution issues.
Innovation Solution
A spinel-type lithium manganese oxide with a phosphate inclusion, characterized by specific particle size, phosphorus/manganese ratio, and BET surface area, is produced using a method involving calcination and disintegration, which enhances its charge-discharge performance by capturing hydrogen fluoride and reducing manganese elution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If spinel-type lithium manganese oxide is used as positive electrode material, then raw material cost is reduced, but manganese elution increases
Solution Approach 1:
The patent applies the intermediary principle by introducing phosphate particles as a mediating substance between the spinel-type lithium manganese oxide and the electrolyte. The phosphate acts as a protective barrier that intercepts and suppresses manganese elution into the electrolyte, while allowing lithium ion transport to continue. This intermediary layer preserves the cost advantage of manganese-based materials by preventing manganese loss
2Reliability
If phosphate is added to spinel-type lithium manganese oxide, then charge-discharge performance at high temperatures is improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-synthesizing phosphate particles with controlled size (0.1-2.0 μm) and pre-mixing them with spinel-type lithium manganese oxide before electrode fabrication. This preliminary preparation of phosphate particles with optimal characteristics simplifies the overall manufacturing process compared to attempting to form phosphate in-situ during electrode processing, as the phosphate is already in the desired size range and distribution state
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 secondary battery demonstrates improved charge-discharge cycle performance at high temperatures with reduced manganese precipitation on the negative electrode, enhancing durability and capacity retention.
Implementation Method 1
the phosphate has an average particle size of 0.1 μm or more and 2.0 μm or less... having a phosphorus/manganese molar ratio of 0.0015 or more and 0.1 or less... excellent in terms of charge-discharge performance at high temperatures
Data Source
AI summary
Provided are a spinel-type lithium manganese oxide excellent in terms of charge-discharge performance at high temperatures and a lithium secondary battery excellent in terms of charge-discharge performance at high temperatures. A spinel-type lithium manganese oxide comprising a phosphate, the spinel-type lithium manganese oxide being represented by chemical formula: Li1+xMn2−X−YMYO4 (where 0.02≤X≤0.20, 0.05≤Y≤0.30, and M represents Al or Mg), wherein the phosphate has an average particle size of 0.1 μm or more and 2.0 μm or less, and primary particles of the spinel-type lithium manganese oxide have an average size of 1.5 μm or more and 5.0 μm or less, a method for producing the spinel-type lithium manganese oxide, and applications of the spinel-type lithium manganese oxide.