LiMnTi Cathode Material via Hydrothermal Ion Exchange for Higher Capacity
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Solution Overview
Problem
Existing LiMnTi-containing oxides with a rock salt structure face challenges in achieving high electric capacity and resource sustainability due to the lack of rare metals like cobalt and nickel, necessitating improvements in their composition and manufacturing process.
Innovation Solution
A method involving hydrothermal treatment of a NaMnTi-containing oxide in a lithium aqueous solution to produce a fine LiMnTi-containing oxide with a rock salt type structure, optimizing the content ratios of lithium, manganese, and titanium, and controlling the particle diameter and lattice constant to enhance electric capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LiMnTi-containing oxide with rock salt structure is used as positive electrode active material, then resource sustainability is improved (no rare metals like cobalt and nickel), but electric capacity is insufficient
Solution Approach 1:
The patent applies parameter changes by optimizing the composition ratios of lithium, manganese, and titanium within specific ranges (Li: 51-56 mol%, Mn: 22-39 mol%, Ti: 10-23 mol%), controlling particle diameter (0.55-1.65 μm), and limiting sodium content (≤0.12 mol%). These parameter optimizations enable the rock salt structure oxide to achieve high electric capacity (≥240 mAh/g) while maintaining resource sustainability without using rare metals like cobalt and nickel.
2Quantity of substance
If hydrothermal treatment is performed to convert tunnel structure to rock salt structure, then electric capacity is improved, but manufacturing process complexity increases
Solution Approach 1:
The patent applies preliminary action by performing hydrothermal treatment in advance to convert the tunnel structure of NaMnTi-containing oxide into the rock salt structure of LiMnTi-containing oxide before electrode fabrication. This preliminary structural transformation ensures high electric capacity (≥240 mAh/g) is achieved in the active material itself, simplifying subsequent electrode manufacturing processes.
Solution Approach 2:
The patent replaces mechanical mixing and sintering processes with hydrothermal treatment, which uses chemical reactions in aqueous solution at elevated temperatures and pressures to directly transform the crystal structure. This substitution enables more precise control over composition and structure, achieving high electric capacity while maintaining manufacturing feasibility.
3Productivity
If particle diameter is reduced to increase surface area, then ion exchange is enhanced, but manufacturing precision becomes more difficult to control
Solution Approach 1:
The patent applies parameter changes by optimizing the particle diameter to a specific range (0.55-1.65 μm, with fine particles at 0.55-1.0 μm). This controlled particle size provides sufficient surface area for enhanced ion exchange and lithium ion insertion/extraction, while remaining within manufacturable precision limits. The hydrothermal treatment process itself helps control particle morphology and size distribution.
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 LiMnTi-containing oxide exhibits higher electric capacity and resource sustainability, with balanced Mn and Ti content, fine particle size, and increased crystallinity, facilitating ion exchange and industrial scalability.
Implementation Method 1
hydrothermal treatment of a fine NaMnTi-containing oxide having a tunnel structure in a lithium aqueous solution
Implementation Method 2
performing a hydrothermal treatment on a NaMnTi-containing oxide in a lithium aqueous solution
Data Source
AI summary
A method for manufacturing a positive electrode active material for a lithium-ion secondary battery according to one embodiment of the present invention comprises a step of performing a hydrothermal treatment on a NaMnTi-containing oxide in a lithium aqueous solution, wherein the NaMnTi-containing oxide contains sodium, manganese, and titanium, has a tunnel type structure, and has an average particle diameter in the range of 0.50 μm or more and 3.00 μm or less.