Nanofilled Solid Polymer Electrolytes for Battery Safety
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Solution Overview
Problem
Solid polymer electrolytes based on polyethylene oxide (PEO) suffer from low conductivity and mechanical instability, leading to dendrite formation and limited battery life, while liquid plasticizers increase flammability risks and decrease stiffness.
Innovation Solution
A crystalline solid electrolyte comprising a PEO6LiX complex stabilized with nanowhiskers, such as cellulose or Al2O3 nanowhiskers, which enhances conductivity and mechanical strength by promoting the formation of PEO6LiX crystalline domains.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If crystalline PEO6LiX complex is used to achieve higher conductivity, then conductivity is improved, but mechanical stability deteriorates leading to dendrite formation
Solution Approach 1:
The patent combines crystalline PEO6LiX complex with nanofillers (such as Al2O3, SiO2, TiO2, or cellulose nanowhiskers) to create a composite solid electrolyte. The nanofillers serve as structural support to maintain mechanical stability while the crystalline PEO6LiX domains provide high ionic conductivity. This composite structure resolves the contradiction by allowing both high conductivity and mechanical stability to coexist.
2Ease of manufacture
If amorphous PEO+LiX is used to achieve ease of manufacture, then manufacturing is simplified, but conductivity and stability deteriorate
Solution Approach 1:
The patent changes the structural parameter of the electrolyte from amorphous to crystalline by controlling the formation of PEO6LiX complexes. This is achieved by selecting specific PEO molecular weights and ratios, and by using nanofillers as nucleation sites during processing. The crystalline structure provides superior conductivity while the nanofiller composite approach maintains ease of manufacture through simple mixing and heating processes.
3Reliability
If liquid plasticizers are added to increase conductivity, then conductivity is improved, but safety deteriorates due to increased flammability
Solution Approach 1:
The patent changes the fundamental state of the electrolyte from liquid-plasticized to solid-crystalline. By forming crystalline PEO6LiX complexes and incorporating nanofillers, the electrolyte achieves high conductivity in a solid state without requiring flammable liquid plasticizers. This parameter change from liquid to solid state eliminates the flammability hazard while maintaining or improving conductivity.
4Strength
If PEO molecular weight is increased to improve mechanical strength, then strength is improved, but conductivity deteriorates due to reduced crystallinity
Solution Approach 1:
The patent uses nanofillers as nucleation sites to promote crystallization in high molecular weight PEO systems. The nanofillers provide surfaces that facilitate the formation of crystalline PEO6LiX domains even in high MW PEO, thereby maintaining both the mechanical strength provided by high MW PEO and the high conductivity provided by crystalline structures.
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 high room temperature conductivity with minimal temperature dependence and increased mechanical strength, decoupling lithium ion conduction from polymer motion, thus preventing dendrite formation and improving battery performance.
Implementation Method 1
crystalline solid electrolyte including a crystalline complex comprising PEO6 and a lithium salt, and at least one nanofiller... which enhances conductivity and mechanical strength by promoting the formation of PEO6LiX crystalline domains
Data Source
AI summary
Embodiments of the disclosure relate to solid electrolytes comprising nanowhiskers. More particularly, embodiments of the disclosure relate to solid electrolytes comprising PEO6LiX crystalline complex and nanowhiskers to stabilize the PEO6LiX crystalline complex.