Lithium Nickel Manganese Oxide Core-Shell Material
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Solution Overview
Problem
Lithium nickel manganese oxide (LNMO) materials in lithium batteries face capacity decay due to Mn3+ inducing disproportionate reactions and structural changes, affecting electrochemical performance and cycle life.
Innovation Solution
A lithium nickel manganese oxide core-shell material is developed, comprising a core and shell with different manganese and nickel ratios, manufactured through a co-precipitation and sintering process, which adjusts the concentration distribution of Mn3+ and Mn4+ to enhance structural stability and discharge rate performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If Mn3+ is present in LNMO to improve discharge rate performance, then discharge rate performance is improved, but structural stability deteriorates due to disproportionate reactions and manganese dissolution
Solution Approach 1:
The patent applies local quality by creating a core-shell structure where the core and shell have different Mn3+ concentrations. The core region contains higher Mn3+ content to enhance discharge rate performance, while the shell region has lower Mn3+ content to maintain structural stability and prevent manganese dissolution. This spatial differentiation of composition allows simultaneous optimization of both discharge rate and structural stability.
Solution Approach 2:
The patent segments the LNMO material into distinct core and shell regions with different chemical compositions. The core contains LiNi0.3Mn1.7O4 with higher Mn3+ content for improved discharge rate, while the shell contains LiNi0.5Mn1.5O4 with lower Mn3+ content for enhanced structural stability. This segmentation allows each region to fulfill its specific functional requirement independently.
2Ease of manufacture
If conventional manufacturing processes are used to produce LNMO, then production simplicity is maintained, but capacity decay occurs due to Mn3+ inducing disproportionate reactions
Solution Approach 1:
The patent applies preliminary action by pre-designing and preparing core and shell precursors with specific compositions before the final sintering process. The core precursor (LiNi0.3Mn1.7O4) and shell precursor (LiNi0.5Mn1.5O4) are prepared separately with controlled Mn3+ concentrations, then combined and sintered to form the core-shell structure. This preliminary preparation ensures the desired composition distribution is achieved while maintaining a relatively simple overall manufacturing process.
3Use of energy by moving object
If nickel content is increased to improve energy density, then energy density is improved, but cost increases due to nickel being more expensive than manganese
Solution Approach 1:
The patent applies parameter changes by optimizing the Ni/Mn ratio in different regions of the core-shell structure. The core region uses a lower Ni content (LiNi0.3Mn1.7O4) to reduce cost, while the shell region uses the conventional stoichiometric ratio (LiNi0.5Mn1.5O4) to maintain energy density performance. This parameter optimization allows cost reduction through decreased nickel usage while preserving the necessary electrochemical performance.
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 core-shell structure improves discharge rate performance and maintains stable cycle life, while reducing costs by replacing nickel with manganese in the core portion, offering superior discharge capability and cost-effectiveness.
Implementation Method 1
a co-precipitation step of mixing a first metal solution and a second metal solution in a container to obtain a co-precipitation product
Implementation Method 2
a sintering step of adding and mixing a lithium salt to the reaction precursor and then performing a sintering treatment thereon
Data Source
AI summary
A lithium nickel manganese oxide core-shell material, comprising a core, composed of a first lithium nickel manganese oxide material; and a shell, covering the core and composed of a second lithium nickel manganese oxide material, wherein the first lithium nickel manganese oxide material and the second lithium nickel manganese oxide material contain manganese and nickel, and the ratio of manganese and nickel in the first lithium nickel manganese oxide material is different from the ratio of manganese and nickel in the second lithium nickel manganese oxide material.