Negative electrode for lithium secondary battery
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Solution Overview
Problem
Lithium secondary batteries experience a reduction in capacity retention rate due to irreversible reactions of lithium metal, necessitating an improvement in capacity retention rate.
Innovation Solution
Incorporating a dielectric particle, such as a complex oxide with a crystal structure of AO2, ABO3, A2B4O7, or (AA′)B4O12, into the negative electrode layer to reduce dendrite growth and enhance the capacity retention rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If lithium metal is used as negative electrode active material, then high output voltage is achieved, but capacity retention rate deteriorates due to irreversible reaction
Solution Approach 1:
A dielectric particle is introduced as an intermediary substance between the lithium metal and the electrolyte. This dielectric particle prevents direct contact and irreversible reaction between lithium metal and electrolyte, thereby improving capacity retention rate while maintaining the high output voltage benefits of lithium metal.
Solution Approach 2:
The invention changes the physical and chemical parameters of the negative electrode by incorporating dielectric particles with specific properties (dielectric constant, particle size, composition). This modification alters the electrochemical behavior of the lithium metal, reducing irreversible reactions and improving capacity retention while preserving high voltage output.
2Reliability
If dielectric particle is added to negative electrode layer, then capacity retention rate is improved, but device complexity increases
Solution Approach 1:
The negative electrode is designed as a composite material system combining lithium metal, dielectric particles, and binder. This composite structure integrates multiple functional components (lithium for high voltage, dielectric particle for protection, binder for structural integrity) to achieve improved capacity retention while maintaining a manageable device structure.
Solution Approach 2:
The dielectric particle is selectively positioned at specific locations within the negative electrode layer where it is most needed for protection. This localized approach optimizes the protective function while minimizing the overall complexity and amount of additional materials required.
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 addition of dielectric particles improves the capacity retention rate by reducing battery resistance and dendrite growth, thereby enhancing the battery's performance.
Implementation Method 1
the dielectric particle may have a relative dielectric constant of 10 to 600
Data Source
AI summary
A negative electrode for a lithium secondary battery includes a negative electrode current collector and a negative electrode layer. The negative electrode layer includes a dielectric particle and a negative electrode active material including either or both of a lithium metal and a lithium alloy.