Sacrificial Negative Electrode for Manganese Deposition Control
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Solution Overview
Problem
Lithium manganese-containing oxides used in lithium secondary batteries experience capacity reduction and rapid cycle deterioration due to Mn2+ ion decomposition and deposition on the negative electrode, leading to electrolyte decomposition.
Innovation Solution
Incorporating a second negative electrode with a specific voltage range to induce Mn2+ deposition, acting as a sacrificial electrode during activation, thereby reducing Mn2+ concentration and minimizing further electrochemical gradients during battery operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If lithium manganese-containing oxides are used as positive electrode active material, then high capacity and environmental friendliness are achieved, but Mn2+ decomposition and deposition on negative electrode occur causing rapid cycle deterioration
Solution Approach 1:
A second negative electrode is introduced as an intermediary component between the positive electrode and the first negative electrode. This second negative electrode acts as a mediator that preferentially deposits Mn2+ ions through electrochemical gradient, preventing Mn2+ from reaching and depositing on the first negative electrode, thus protecting the main negative electrode and maintaining cycle characteristics while preserving high capacity
2Stability of the object's composition
If Mn2+ is deposited on the negative electrode, then electrochemical gradient is formed, but electrolyte decomposition is accelerated reducing battery lifespan
Solution Approach 1:
The harmful effect of Mn2+ deposition on the first negative electrode is extracted and isolated by introducing a second negative electrode. This second negative electrode selectively captures Mn2+ ions that would otherwise decompose the electrolyte at the first negative electrode, thereby removing the harmful factor while maintaining the necessary electrochemical gradient for battery operation
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
This approach significantly reduces Mn2+ deposition on the first negative electrode, maintaining battery performance and cycle characteristics by managing electrochemical gradients and preventing electrolyte decomposition.
Implementation Method 1
Mn2+ is deposited on a negative electrode due to an electrochemical gradient formed within a battery cell
Implementation Method 2
Mn2+ is deposited at approximately 1.86 V or less with respect to Li/Li+, voltage of the second negative electrode may be 1.86 V or less in order for deposition of Mn2+
Implementation Method 3
a separator disposed between the positive electrode and the first negative electrode or second negative electrode
Data Source
AI summary
Disclosed is a battery cell having an electrode assembly that is sealed with an electrolyte solution within a battery case, the electrode assembly including one or more positive electrodes to which a positive electrode terminal is connected; one or more first negative electrodes to which a first negative electrode terminal is connected; one or more second negative electrodes to which a second negative electrode terminal is connected; and a separator disposed between the positive electrode and the first negative electrode or second negative electrode, or a separator disposed between the positive electrode and the first negative electrode or second negative electrode and a separator disposed between the first negative electrode and the second negative electrode.