Composite Solid Electrolyte Membrane for Flame-Retardant Li Batteries
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Solution Overview
Problem
Commercially available lithium secondary batteries face safety issues such as leakage, ignition, and explosion due to sudden environmental changes, and there is a need for improved mechanical properties and high-temperature stability in secondary battery electrolytes.
Innovation Solution
An electrolyte for a secondary battery comprising a lithium salt, a composite membrane with an inorganic electrolyte and an organic binder, and a flame retardant compound, where the inorganic electrolyte content is 50% to 95% by volume, the organic binder is 5% to 50% by volume, and the flame retardant compound is 0.01 to 0.3 times the inorganic electrolyte content, with phosphorus-containing functional groups and fluorine atoms enhancing flame retardancy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If liquid electrolytes are used in lithium secondary batteries, then electrochemical performance is maintained, but safety issues such as leakage, ignition, and explosion occur due to environmental changes
Solution Approach 1:
The patent transitions the electrolyte from liquid phase to solid phase by forming a composite membrane with inorganic electrolyte particles and organic binder. This phase transition eliminates the leakage, ignition, and explosion issues associated with liquid electrolytes while maintaining electrochemical functionality through solid-state ion conduction.
Solution Approach 2:
The patent creates a composite membrane combining inorganic electrolyte particles (providing ion conduction and thermal stability) with organic binder (providing mechanical integrity and flexibility). This composite structure achieves both safety improvements and functional performance by integrating the advantages of different material types.
2Reliability
If solid-state electrolytes are used to enhance stability, then safety against ignition and explosion is improved, but mechanical properties need enhancement
Solution Approach 1:
The composite membrane combines brittle inorganic electrolyte particles with flexible organic binder material. The inorganic particles provide thermal stability and ion conduction, while the organic binder provides mechanical strength and flexibility, achieving both stability and enhanced mechanical properties through material composition.
Solution Approach 2:
The patent optimizes the volume ratio of inorganic electrolyte particles to organic binder (50:50 to 95:5) to balance mechanical strength and stability. By adjusting this parameter, the composite membrane achieves sufficient mechanical integrity while maintaining the thermal stability benefits of the inorganic electrolyte.
3Temperature
If inorganic electrolyte content is increased to improve stability, then high-temperature stability is enhanced, but mechanical flexibility may deteriorate
Solution Approach 1:
The patent establishes an optimal range for inorganic electrolyte content (50-95 vol%) and organic binder content (5-50 vol%). Within this range, the composite membrane achieves both high-temperature stability from the inorganic phase and adequate mechanical flexibility from the organic phase, resolving the trade-off between these properties.
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 electrolyte exhibits improved mechanical properties, self-extinguishing capabilities, and enhanced stability at both room-temperature and high-temperature, thereby improving safety and electrical characteristics.
Implementation Method 1
a composite membrane including an inorganic electrolyte and an organic binder
Implementation Method 2
a flame retardant compound, wherein the content of the inorganic electrolyte, based on the total volume of the composite membrane, may be 50% by volume to 95% by volume
Data Source
Figure 1~2
Figure 3~4
AI summary
An electrolyte for a lithium secondary battery according to embodiments of the present disclosure may include a lithium salt, a composite membrane including an inorganic electrolyte and an organic binder, and a flame retardant polymer. A lithium secondary battery according to embodiments of the present disclosure may include a cathode, an anode disposed to face the cathode, and an electrolyte layer disposed between the cathode and the anode which includes the electrolyte for a secondary battery.