LLZBO-PEO Composite Electrolyte for High Ionic Conductivity
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Solution Overview
Problem
Conventional liquid electrolytes in lithium-based batteries pose safety risks due to dendritic growth and thermal runaway, while solid-state electrolytes suffer from low ionic conductivity, limiting battery safety, lifetime, and capacity.
Innovation Solution
A composite ceramic-polymer solid-state electrolyte is developed using bismuth-doped lithium lanthanum zirconium oxide (LLZBO) mesoparticles embedded in poly(ethylene oxide) (PEO), synthesized via the Pechini sol-gel method at low temperatures, enhancing ionic conductivity through optimized particle size and distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional liquid electrolytes are used in lithium-based batteries, then ionic conductivity is high, but safety issues and thermal runaway occur due to dendritic growth
Solution Approach 1:
The patent employs a composite solid-state electrolyte system combining LLZBO ceramic particles with PEO polymer matrix. This composite structure eliminates the harmful effects of liquid electrolytes (dendritic growth and thermal runaway) while maintaining high ionic conductivity through the synergistic interaction between the ceramic filler and polymer matrix, resolving the safety versus performance contradiction
2Reliability
If solid-state electrolytes are used to improve safety, then thermal stability increases, but ionic conductivity decreases by orders of magnitude
Solution Approach 1:
The patent optimizes multiple parameters to enhance ionic conductivity in solid-state electrolytes: (1) doping LLZO with bismuth to create LLZBO with higher intrinsic conductivity, (2) controlling particle size at mesoscale (1-500 microns) to maximize surface area and interfacial effects, (3) optimizing the weight percentage of LLZBO (5-50 wt%) in the PEO matrix, and (4) operating at elevated temperatures (35-55°C) where the composite achieves conductivity values of 1.09×10⁻⁴ to 5.45×10⁻³ S/cm
Solution Approach 2:
The composite structure combines the thermal stability of LLZBO ceramic particles with the flexible ion-conducting PEO polymer matrix. The ceramic particles serve as both structural stabilizers and active ion-conduction pathways, while the polymer provides flexibility and continuous ion transport channels, achieving both high safety and high ionic conductivity simultaneously
3Reliability
If high ionic conductivity is achieved through optimized composite electrolyte, then battery performance improves, but synthesis complexity increases
Solution Approach 1:
The patent employs the Pechini sol-gel method to pre-form LLZBO ceramic particles with controlled stoichiometry and morphology before incorporating them into the PEO matrix. This preliminary synthesis step allows precise control over particle composition (Li7-xLa3Zr2-xBixO12) and size (1-500 microns), simplifying the overall fabrication process by separating material synthesis from composite assembly
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 electrolyte achieves high ionic conductivity, improving battery safety and mechanical flexibility with ionic conductivity values up to one order of magnitude higher than previous systems, reducing synthesis costs and energy demands.
Implementation Method 1
synthesized via the Pechini sol-gel method at low temperatures
Implementation Method 2
ionic transport through solid electrolyte materials is orders of magnitude lower than that through liquid electrolytes. If the ionic conductivity mechanisms and the fabrication of solid-state electrolyte materials capable of conducting Li-ions can be optimized
Data Source
AI summary
A method of controlling the ionic conductivity of a polymer member, including providing a plurality of particles of bi-doped garnet, dispersing the plurality of particles of bi-doped garnet in a PEO matrix to yield a polymer member, nucleating spherulites at bi-doped garnet particle sites, and growing spherulites to a critical density to provide ionic conductivity pathways throughout the polymer member.