Self-Healing Separator Precursors for Lithium Metal Batteries
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Solution Overview
Problem
Lithium metal batteries experience premature failure due to dendrite growth from the anode to the cathode, and existing separators fail to effectively prevent or heal defects caused by this growth.
Innovation Solution
The development of methods and compositions for forming and healing separators in rechargeable electrochemical cells, where a precursor in the electrolyte reacts to form a separator or heal defects when electrodes are held at specific voltages, utilizing halide anions and species that can react to form halide anions, and employing self-healing halide-based chemistry to create a stable solid electrolyte interface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separator is added to arrest dendrite growth, then battery safety is improved, but the separator becomes damaged and loses its utility once dendrites grow through it
Solution Approach 1:
The patent applies preliminary action by pre-loading the electrolyte with separator precursors (lithium halide salts) before battery operation. These precursors are positioned in advance within the electrolyte, ready to react and form separator material at critical locations when dendrites threaten to breach the separator, thereby extending the separator's functional life beyond its initial physical structure.
Solution Approach 2:
The patent implements self-service through the automatic reaction of lithium halide salt precursors with water or hydroxyl groups at dendrite penetration sites. This self-healing mechanism occurs without external intervention, where the precursor materials autonomously react to reform separator material exactly where damage occurs, maintaining battery safety continuously.
2Reliability
If the electrolyte contains a high concentration of separator precursor, then separator formation and healing is improved, but the electrolyte viscosity increases and ionic conductivity decreases
Solution Approach 1:
The patent applies parameter changes by optimizing the concentration of lithium halide salt precursors to specific ranges (0.1-10 mM, preferably 0.5-5 mM). This precise parameter control ensures sufficient precursor availability for effective separator formation and healing while maintaining electrolyte fluidity and ionic conductivity, resolving the trade-off between separator effectiveness and ion transport efficiency.
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 enhances the cycle life and safety of lithium metal batteries by preventing dendrite growth and self-healing defects, improving lithium cycling efficiency and suppressing dendrite formation, while maintaining mechanical strength and electrochemical stability.
Implementation Method 1
The first voltage causes the precursor for the separator to react to form a separator positioned between the first electrode and a second electrode
Implementation Method 2
The first voltage may cause the precursor for the separator to react to heal a defect in the separator
Implementation Method 3
Separators have been added to lithium metal batteries to arrest dendrite growth
Implementation Method 4
employing self-healing halide-based chemistry to create a stable solid electrolyte interface
Data Source
AI summary
The present invention is generally related to separators for use in lithium metal batteries, and associated systems and products. Certain embodiments are related to separators that form or are repaired when an electrode is held at a voltage. In some embodiments, an electrochemical cell may comprise an electrolyte that comprises a precursor for the separator.