Ceramic-Polymer Solid Electrolyte for High Conductivity and Dendrite Blocking
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Solution Overview
Problem
Current solid polymer electrolytes in electrochemical cells face challenges such as low ionic conductivity, poor mechanical strength, and lithium dendrite growth, which hinder the development of high-performance batteries.
Innovation Solution
A ceramic-polymer nanocomposite solid-state electrolyte is developed, where ionic conductive ceramic nanoparticles (AlxLi7-xLa3Zr1.75Ta0.25O12) are embedded in an amorphous polymer matrix, enhancing ionic conductivity and mechanical strength while preventing lithium dendrite growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a plasticizer is added to improve polymer chain mobility and ionic conductivity at room temperature, then ionic conductivity is enhanced, but mechanical strength deteriorates
Solution Approach 1:
The patent employs a composite material system consisting of polymer matrix, ceramic nanoparticles (LLZO), and plasticizer. The ceramic nanoparticles provide mechanical reinforcement while the plasticizer maintains ionic conductivity. This composite approach allows simultaneous achievement of both improved ionic conductivity and maintained mechanical strength, resolving the contradiction between these two properties.
2Ease of manufacture
If solid electrolyte layers are stacked onto cathode layers, then cell assembly is simplified, but intimate contact between electrode and electrolyte is reduced, decreasing effective area for Li ion transport
Solution Approach 1:
The patent utilizes porous cathode structures and interfaces that allow solid electrolyte to diffuse into the cathode material pores. This creates intimate contact between the electrolyte and electrode surfaces, significantly increasing the effective area for Li ion transport while maintaining the simplicity of stacked cell assembly.
3Reliability
If conventional organic liquid electrolytes are used, then ionic conductivity is high, but safety deteriorates due to flammability and toxicity
Solution Approach 1:
The patent develops a composite solid electrolyte system combining polymer matrix, ceramic nanoparticles (LLZO with formula AlxLi7-xLa3Zr1.75Ta0.25O12), and plasticizer. This composite achieves ionic conductivity greater than 1×10−3 S/cm at room temperature while eliminating the flammability and toxicity associated with conventional organic liquid electrolytes, thus resolving the safety-conductivity contradiction.
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 ceramic-polymer nanocomposite electrolyte achieves high ionic conductivity (>1×10−3 S/cm at room temperature), excellent chemical/electrochemical stability, and enhanced mechanical strength, leading to improved cycling stability and high specific capacitance at high charge-discharge rates.
Implementation Method 1
ionic conductive ceramic nanoparticles (AlxLi7-xLa3Zr1.75Ta0.25O12) are embedded in an amorphous polymer matrix, enhancing ionic conductivity
Implementation Method 2
Due to the strong coordination between Li ions and the polymer chain, chain-assisted Li ion transport mechanism is less effective at room temperature or below the melting temperature of the polymer
Data Source
AI summary
A ceramic-polymer film includes a polymer matrix; a plasticizer; a lithium salt; and AlxLi7-xLa3Zr1.75Ta0.25O12 where x ranges from 0.01 to 1 (LLZO), wherein the LLZO are nanoparticles with diameters that range from 20 to 2000 nm and wherein the film has an ionic conductivity of greater than 1×10−3 S/cm at room temperature. The nanocomposite film can be formed on a substrate and the concentration of LLZO nanoparticles decreases in the direction of the substrate to form a concentration gradient over the thickness of the film. The film can be employed as a non-flammable, solid-state electrolyte for lithium electrochemical cells and batteries. The LLZO serves as a barrier to dendrite growth.