Crosslinked Solid Electrolyte for Stable Battery Cycling
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Solution Overview
Problem
Lithium-based solid-state batteries face challenges with stable cycling and mechanical strength due to low ionic conductivity and high lithium dendrite growth in existing PEO-based electrolytes, which limits their commercial acceptance and application in energy storage systems.
Innovation Solution
A solid electrolyte composition is developed, comprising a crosslinked organic polymer with inorganic components like glass fibers and metal ions, providing high shear modulus and ionic conductivity through hydrogen and ionic bonding, and incorporating a plasticizer to enhance mechanical strength and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high molecular weight linear PEO is used as solid electrolyte, then chemical stability with Li metal is improved, but ionic conductivity deteriorates (10^-7-10^-6 S/cm)
Solution Approach 1:
The patent creates a composite solid electrolyte system combining PEO polymer matrix with lithium salts (LiTf, LiClO4, LiBF4) and plasticizers (EC, DEC, DMF). This composite approach allows the PEO to provide chemical stability while the lithium salts and plasticizers work together to enhance ionic conductivity to levels comparable with liquid electrolytes, resolving the contradiction between stability and conductivity.
Solution Approach 2:
The patent systematically varies multiple parameters including PEO molecular weight, lithium salt concentration (0.5-2.0 M), and plasticizer content (10-50 wt%) to optimize the balance between chemical stability and ionic conductivity. By adjusting these parameters, the electrolyte achieves both high stability with Li metal and sufficient ionic conductivity for practical battery operation.
2Quantity of substance
If plasticizers and large anion lithium salts are added to improve ionic conductivity, then conductivity is improved, but mechanical rigidity deteriorates (storage moduli E'm at 65°C)
Solution Approach 1:
The patent optimizes the concentration ratios of plasticizers and lithium salts to achieve the desired balance. By controlling the plasticizer content at 10-50 wt% and lithium salt concentration at 0.5-2.0 M, the electrolyte maintains adequate mechanical rigidity at operating temperatures while achieving ionic conductivity comparable to liquid electrolytes.
Solution Approach 2:
The composite formulation combining PEO, lithium salts, and plasticizers in specific ratios creates a synergistic effect where the polymer matrix provides mechanical structure while the additives enhance ionic conductivity without excessive softening, resolving the rigidity-conductivity trade-off.
3Quantity of substance
If PEO-based electrolyte is used above 65°C, then ionic conductivity may improve, but mechanical strength deteriorates (behaves like liquid)
Solution Approach 1:
The patent selects plasticizers with appropriate boiling points and molecular weights, and optimizes their concentration to ensure the electrolyte maintains liquid-like ionic conductivity at elevated temperatures while retaining sufficient mechanical strength through the PEO matrix structure.
Solution Approach 2:
The composite PEO-lithium salt-plasticizer system maintains a semi-solid state at elevated temperatures, combining the benefits of liquid electrolytes (high ionic conductivity) with the advantages of solid electrolytes (mechanical strength and safety), enabling operation above 65°C without complete loss of structural integrity.
4Object-affected harmful factors
If mechanical rigidity is increased to suppress lithium dendrite growth, then dendrite suppression is improved, but ionic conductivity deteriorates
Solution Approach 1:
The patent creates a composite electrolyte with optimized composition that achieves mechanical rigidity sufficient to suppress lithium dendrite growth while maintaining high ionic conductivity through the synergistic combination of PEO, lithium salts, and plasticizers. The specific formulation balances mechanical strength and ionic transport properties.
Solution Approach 2:
By optimizing the molecular weight of PEO, concentration of lithium salts, and content of plasticizers, the patent achieves a critical threshold of mechanical rigidity for dendrite suppression while maintaining ionic conductivity levels adequate for high-rate battery operation, resolving the contradiction between mechanical strength and ionic conductivity.
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 solution achieves exceptionally high shear modulus and stable cycling for over 100 cycles at 70°C without dendritic growth, demonstrating improved mechanical strength and ionic conductivity, suitable for solid-state batteries and other energy storage applications.
Implementation Method 1
an inorganic component having a metal oxide or metal sulfide composition, and which is distributed throughout the crosslinked organic polymer and interacts by hydrogen bonding with the crosslinked organic polymer
Implementation Method 2
stable cycling of lithium metal requires a chemically and interfacially stable solid-state separator with high ionic conductivity
Data Source
AI summary
A solid electrolyte (SE) composition comprising: (i) a crosslinked organic polymer containing at least one of oxygen and nitrogen atoms; (ii) an inorganic component having a metal oxide or metal sulfide composition and which is distributed throughout the crosslinked organic polymer and interacts by hydrogen bonding with the crosslinked organic polymer; and (iii) metal ions selected from the group consisting of lithium, sodium, potassium, magnesium, calcium, zinc, and aluminum. Also described herein are solid-state batteries comprising: a) an anode; (b) a cathode; and (c) the solid electrolyte composition described above. Also described herein is a method for producing the SE composition, comprising: a) homogeneously mixing the following components: (i) an organic polymer; (ii) an inorganic component; (iii) metal ions, and (iv-b) a low-boiling solvent functioning to dissolve components (i) and (iii); (b) crosslinking the organic polymer to produce a crosslinked organic polymer; and (c) removing the low-boiling solvent.