Negative Electrode Structure Using a Field Electrode Against Dendrites
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Solution Overview
Problem
Lithium metal batteries face safety issues due to the growth of lithium dendrites during cycling, which can lead to instability, electrolyte consumption, and potential internal short circuits.
Innovation Solution
A lithium-ion secondary battery design featuring a field electrode near the negative electrode to create an electric field that modifies cation distribution, reducing the likelihood of dendrite formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If lithium metal is used as anode material to achieve high energy density, then specific capacity and energy density are improved, but lithium dendrite growth occurs causing safety issues
Solution Approach 1:
A field electrode is introduced as an intermediary component between the positive and negative electrodes. This field electrode generates an electric field that acts as a mediator to control lithium ion deposition, preventing direct harmful interaction between lithium metal and electrolyte that leads to dendrite formation, while maintaining the high energy density benefits of lithium metal anodes
2Productivity
If lithium dendrites grow during charging, then lithium ions are reduced and deposited, but interface instability occurs and SEI film is destroyed
Solution Approach 1:
The field electrode applies a preliminary counteracting electric field during the charging process that opposes the formation of lithium dendrites before they can grow. This preliminary anti-action prevents the destructive interaction between lithium ions and the SEI film, maintaining interface stability while allowing efficient lithium ion deposition
3Reliability
If field electrode is added to suppress lithium dendrite growth, then safety and stability are improved, but device complexity increases
Solution Approach 1:
The field electrode is positioned locally near the negative electrode where lithium dendrite formation occurs, rather than requiring a complete redesign of the entire battery structure. This localized approach provides the necessary electric field control to suppress dendrites while minimizing the increase in overall device complexity
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 additional field electrode effectively suppresses lithium dendrite growth, enhancing the stability and safety of lithium-ion batteries by promoting even cation deposition and increasing the energy barrier for dendrite nucleation.
Implementation Method 1
featuring an additional field electrode near negative electrode for providing an electric field to modify the distribution of cations in the reduction of negative electrode
Data Source
AI summary
A lithium-ion secondary battery is provided in the present disclosure, including a positive electrode with a first current collector and a first active material, a negative electrode, a separator between the positive electrode and the negative electrode, a field electrode at one side of the negative electrode opposite to the positive electrode, and a first insulating layer isolated between the negative electrode and the field electrode.