Li-rich Transition Metal Oxide Coating for Secondary Battery Efficiency
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Solution Overview
Problem
Li-rich transition metal oxides in secondary batteries suffer from high surface reactivity, leading to electrolyte decomposition and low initial efficiency due to side reactions.
Innovation Solution
Incorporating a dicarboxylic acid and/or its anhydride into the positive electrode material to form a coating on the Li-rich transition metal oxide, reducing surface reactivity and suppressing electrolyte decomposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If Li-rich transition metal oxide is used as positive electrode active material, then theoretical capacity is improved, but initial efficiency deteriorates due to high surface reactivity and electrolyte decomposition
Solution Approach 1:
A coating layer comprising a dicarboxylic acid and/or an anhydride of the dicarboxylic acid is introduced as an intermediary between the Li-rich transition metal oxide and the electrolyte. This coating layer suppresses direct contact and harmful interactions between the high-reactivity oxide surface and the electrolyte, thereby improving initial efficiency while preserving the high capacity benefits of the Li-rich material.
Solution Approach 2:
The chemical composition and surface properties of the positive electrode material are modified by introducing dicarboxylic acid/anhydride compounds. This changes the surface chemistry parameters of the Li-rich transition metal oxide, reducing its reactivity toward the electrolyte and suppressing decomposition reactions, thus improving initial efficiency without sacrificing theoretical capacity.
2Quantity of substance
If Li-rich transition metal oxide is used, then capacity is improved, but side reactions increase due to high surface reactivity
Solution Approach 1:
The dicarboxylic acid/anhydride coating acts as a protective intermediary layer that physically separates the Li-rich transition metal oxide surface from the electrolyte. This prevents direct harmful interactions and side reactions between the high-reactivity oxide and electrolyte components, while allowing the underlying material to maintain its high capacity functionality.
Solution Approach 2:
The coating layer is applied in advance to the Li-rich transition metal oxide surface before battery operation. This preliminary protective action prevents harmful side reactions from occurring by blocking the reactive surface sites that would otherwise facilitate electrolyte decomposition and other parasitic reactions.
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 coating improves the initial efficiency of secondary batteries by reducing side reactions and enhancing the stability of the positive electrode material.
Implementation Method 1
Incorporating a dicarboxylic acid and/or its anhydride into the positive electrode material to form a coating on the Li-rich transition metal oxide, reducing surface reactivity and suppressing electrolyte decomposition.
Data Source
AI summary
A positive electrode material for secondary batteries, the material including a Li-rich transition metal oxide having a lithium-to-oxygen atomic ratio: Li/O of 0.8 or more, and a dicarboxylic acid and/or an anhydride of the dicarboxylic acid.