Composite Polymer Electrolyte for Flame-Retardant Solid-State Batteries
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Solution Overview
Problem
Lithium secondary batteries face safety issues due to electrolyte leakage and flammability, as well as limitations in preventing ignition and lithium dendrite growth, with existing polymer electrolytes lacking flame retardancy and mechanical strength.
Innovation Solution
An organic and inorganic composite polymer electrolyte is developed, incorporating a flame-retardant polymer and inorganic salt with a shear modulus of 7 to 60 GPa, which includes phosphorus-based, phosphazene-based, and fluorinated polymers, and fluoride or carbonate inorganic salts to enhance flame retardancy and mechanical properties, while suppressing lithium dendrite growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a liquid electrolyte is used in lithium secondary batteries, then ionic conductivity is improved, but safety deteriorates due to electrolyte leakage and flammability
Solution Approach 1:
The patent uses a composite polymer electrolyte consisting of a polymer matrix (such as polyethylene oxide) combined with inorganic fillers (such as lithium phosphate, lithium metasilicate, or aluminum phosphate). This composite structure provides both the ionic conductivity needed for battery operation and the mechanical strength needed to prevent leakage and reduce flammability risks.
Solution Approach 2:
The patent changes the physical state of the electrolyte from liquid to solid gel form by incorporating polymer matrices and inorganic fillers. This parameter change maintains ionic conductivity while eliminating the leakage and flammability issues associated with liquid electrolytes.
2Strength
If existing polymer electrolytes are used, then mechanical properties are improved, but flame retardancy deteriorates because they lack flame-retardant polymers and functional inorganic salts
Solution Approach 1:
The patent creates a composite material combining flame-retardant polymers (such as phosphorus-based polymers, phosphazene-based polymers, fluorinated polymers, or ionic polymers) with functional inorganic salts. This composite provides both enhanced mechanical properties and flame retardancy.
Solution Approach 2:
The patent modifies the chemical composition of the polymer electrolyte by incorporating specific flame-retardant functional groups and inorganic salts, changing the material's thermal and mechanical properties to achieve both strength and flame retardancy.
3Strength
If inorganic material is added to improve mechanical properties, then strength is improved, but flame retardancy deteriorates because the inorganic material is not aimed at securing flame retardancy
Solution Approach 1:
The patent selects inorganic materials with specific local qualities - particularly shear modulus in the range of 7 to 60 GPa - that provide both mechanical strength and flame retardancy. The inorganic fillers are distributed throughout the polymer matrix to provide localized flame-retardant action where needed.
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 composite polymer electrolyte effectively prevents ignition, reduces electrolyte leakage, and improves mechanical strength, thereby enhancing the safety and lifespan of lithium secondary batteries by capturing radicals and blocking oxygen to extinguish flames and suppressing lithium dendrite formation.
Implementation Method 1
The flame-retardant inorganic salt may generate an F radical or CO 2 by thermal decomposition
Implementation Method 2
strengthening mechanical properties of the electrolyte, preventing short circuits in a battery, and suppressing growth of a lithium dendrite
Data Source
Figure 1A~1B
Figure 2
AI summary
Provided is an organic and inorganic composite polymer electrolyte and an all-solid-state battery including the same, and provided is an organic and inorganic composite polymer electrolyte including a flame-retardant polymer and a flame-retardant inorganic salt with a shear modulus of 7 to 60 GPa, and an all-solid-state battery including the organic and inorganic composite polymer electrolyte.