Composite Solid Electrolyte With LiFePO4 for Low-Temperature Conductivity
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Solution Overview
Problem
Conventional liquid or gel electrolytes in lithium-ion batteries pose safety concerns due to flammability and leakage, and solid polymer electrolytes often have poor conductivity at low temperatures, limiting their application in both portable devices and electric vehicles.
Innovation Solution
A composite solid electrolyte comprising a solid polymer with lithium salt and lithium iron phosphate, combined with phyllosilicate nanoparticles, which enhances lithium ion conductivity and compatibility with lithium iron phosphate cathodes, forming a flexible thin membrane for improved safety and performance across a wide temperature range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional liquid or gel electrolytes are used, then satisfactory conductivity and electrode contact are achieved, but safety concerns arise due to solvent leakage and flammability
Solution Approach 1:
The patent employs a composite solid electrolyte comprising a solid polymer matrix (such as PEO) combined with lithium iron phosphate particles and lithium salts. This composite structure eliminates the flammable liquid components while maintaining ionic conductivity through the solid polymer phase, directly resolving the safety contradiction by replacing hazardous materials with a non-flammable composite alternative.
2Object-generated harmful factors
If solid polymer electrolytes are used to eliminate flammability, then safety is improved, but conductivity at low temperatures deteriorates
Solution Approach 1:
The patent modifies the physical and chemical parameters of the solid polymer electrolyte by incorporating lithium iron phosphate particles and optimizing the lithium salt content. These parameter changes enhance the ionic conductivity of the polymer matrix, allowing it to maintain adequate performance at lower temperatures while preserving the safety benefits of the solid state structure.
Solution Approach 2:
By creating a composite solid electrolyte with lithium iron phosphate dispersed in the polymer matrix, the patent combines materials with complementary properties. The lithium iron phosphate enhances ionic conductivity without compromising the non-flammable nature of the solid polymer, thus resolving the contradiction between safety and low-temperature performance.
3Adaptability or versatility
If lithium iron phosphate is distributed in the solid polymer, then compatibility with cathodes is improved, but manufacturing complexity increases
Solution Approach 1:
The patent combines the electrolyte function with the cathode compatibility function into a single integrated solid polymer electrolyte layer containing lithium iron phosphate. This merging eliminates the need for separate interface layers or complex assembly processes, reducing manufacturing complexity while ensuring optimal compatibility between the electrolyte and lithium iron phosphate cathodes.
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 solid electrolyte provides safe, non-flammable, and lightweight batteries with adequate lithium ion conductivity at room temperature, suitable for various applications, including electric vehicles and portable devices, while maintaining performance from -10°C to 100°C.
Implementation Method 1
a lithium salt distributed in the solid polymer, and lithium iron phosphate distributed in the solid polymer
Implementation Method 2
The composite solid electrolyte can have a lithium ion conductivity of at least 10−4 S cm−1 at 25° C.
Data Source
AI summary
A composite solid electrolyte (410) for lithium batteries can include a solid polymer (440), a lithium salt (450) distributed in the solid polymer (440), and lithium iron phosphate (460) distributed in the solid polymer (440). A solid state lithium battery cell (400) can include a composite solid electrolyte layer (410), an anode (420) containing lithium in contact with a first surface of the composite solid electrolyte layer (410): and a cathode (430) in contact with a second surface of the composite solid electrolyte layer (410). The composite solid electrolyte layer (410) can include a solid polymer (440), a lithium salt (450) distributed in the solid polymer (440), and lithium iron phosphate (460) distributed in the solid polymer (440).