Conformal Solid Electrolyte Coatings for Lithium-Ion Battery Safety
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Solution Overview
Problem
Conventional lithium-ion batteries face challenges in energy density, cycle life, and safety due to the breakdown of polymeric separators under high temperatures, chemical, and mechanical stress, leading to internal short circuits and thermal runaway.
Innovation Solution
The implementation of hybrid solid-liquid electrolyte lithium-ion batteries with conformal coatings of electron-insulating and lithium-ion conductive solid electrolyte layers on electrodes, either as a replacement or in addition to polymeric separators, using atomic layer deposition to prevent electron passage and enhance mechanical integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polymeric separators are used to provide spatial and electrical separation between electrodes, then electrical separation is achieved, but mechanical integrity deteriorates under high temperatures, chemical stress and mechanical stress
Solution Approach 1:
The patent applies composite materials by combining polymeric separator with conformal solid electrolyte coatings on electrode surfaces. The solid electrolyte layer (e.g., Al2O3, Li3PO4) forms a composite structure with the polymeric separator, where the inorganic coating provides thermal and mechanical stability while the polymer provides flexibility and ion transport pathways. This composite approach resolves the contradiction by maintaining electrical separation reliability while improving mechanical integrity under stress conditions.
Solution Approach 2:
The patent implements local quality by applying solid electrolyte coatings specifically at the electrode surfaces where contact with the separator occurs. Rather than modifying the entire separator structure, the conformal coating is applied locally to the electrode surfaces, providing enhanced mechanical and thermal stability precisely where needed for electrical separation, while preserving the overall flexibility and ion transport properties of the polymeric separator.
2Quantity of substance
If separator thickness is reduced to improve energy density, then energy density increases, but safety deteriorates due to increased risk of internal short circuits
Solution Approach 1:
The patent applies parameter changes by modifying the functional properties of the separator system through conformal solid electrolyte coatings. The coating changes the surface properties of the electrodes, creating an electron-insulating layer that enhances safety even when the overall separator thickness is reduced. This allows energy density improvement through thinner separators while maintaining or enhancing safety through the protective coating layer.
Solution Approach 2:
The patent substitutes mechanical safety mechanisms (thick polymeric separator providing physical barrier) with a combined approach where conformal solid electrolyte coatings provide electronic insulation and safety functions. The coating layer replaces the need for excessive mechanical thickness by providing electron insulating properties at the molecular level, allowing thinner overall separator structures that improve energy density while maintaining safety.
3Reliability
If conformal solid electrolyte layers are deposited on electrodes to prevent internal short circuits, then safety improves, but device complexity increases
Solution Approach 1:
The patent merges multiple functions into the conformal solid electrolyte coating layer. The coating simultaneously provides electron insulation to prevent internal short circuits, serves as an additional ion transport pathway, and protects the electrode surfaces from direct contact with the liquid electrolyte. This merging of multiple safety and functional roles into a single conformal layer improves safety while minimizing the increase in device complexity compared to adding separate components.
Solution Approach 2:
The patent employs thin film technology by depositing conformal solid electrolyte layers (e.g., Al2O3, Li3PO4) with controlled thickness in the nanometer to micrometer range. These thin films provide the necessary safety functions (electron insulation, mechanical integrity) without adding significant structural complexity or volume. The conformal nature of the coating ensures uniform protection across complex electrode geometries, maintaining simplicity in the overall device architecture.
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
This solution improves the safety and durability of lithium-ion batteries by preventing internal short circuits and heat generation, reducing the risk of thermal runaway, and maintaining electrochemical performance comparable to conventional batteries.
Implementation Method 1
The solid electrolyte layer comprises an additional electrolyte and, in various aspects, is used in addition to a liquid electrolyte. The solid electrolyte layers deposited on the electrodes serve as electric insulators, they prevent passage of electrons across them.
Implementation Method 2
The solid electrolyte layer is electron insulating and lithium ion conductive
Implementation Method 3
a self-limiting deposition process, such as atomic layer deposition (ALD), can be used to deposit the conformal solid electrolyte layers onto the cathode and anode electrodes
Implementation Method 4
the solid electrolyte layers protect the anode and the cathode from direct contact with a liquid electrolyte, thereby improving the cycle life of the battery and resulting in less heat generation by electrode/electrolyte reactions
Data Source
AI summary
Hybrid solid-liquid electrolyte lithium-ion battery devices are disclosed. Certain devices comprise anodes and cathodes conformally coated with an electron insulating and lithium ion conductive solid electrolyte layer.