Ion-Conductor Separator Composite for Battery Electrode Protection
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Solution Overview
Problem
Existing electrochemical cell protective layers, particularly those using ceramic and polymer combinations, are prone to defects and swelling issues that lead to mechanical failure and electrolyte penetration, compromising the integrity of lithium anodes.
Innovation Solution
The use of an ion-conducting material, such as a ceramic or glassy-ceramic ion conductor, is integrated into a separator matrix or applied as a thin layer adjacent to the separator, which fills pores or protrudes into the separator, enhancing adhesion and mechanical stability while inhibiting electrolyte interaction with the electroactive material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ceramic and polymer protective layers are used, then electrode protection is provided, but defects and swelling lead to mechanical failure and electrolyte penetration
Solution Approach 1:
The patent employs a composite structure consisting of a porous polymer separator matrix combined with an inorganic ion-conducting material. The inorganic material fills the pores of the polymer separator, creating a composite that combines the flexibility and porosity of the polymer with the mechanical strength and chemical stability of the inorganic material. This composite structure prevents the defects and swelling issues that plague single-material protective layers while maintaining ion conductivity.
Solution Approach 2:
The patent utilizes a porous polymer separator as the base matrix, which provides necessary ion transport pathways. The pores are then filled with inorganic ion-conducting material, creating a hierarchical porous structure that maintains ion conductivity while preventing electrolyte penetration. The porous structure allows ions to pass through while the inorganic filling prevents direct contact between electrolyte and the electrode.
2Reliability
If protective layers are made thinner to improve ion conductivity, then ion transport is enhanced, but mechanical strength and defect resistance decrease
Solution Approach 1:
The composite of porous polymer and inorganic ion-conducting material allows for thin film construction while maintaining mechanical strength. The inorganic material provides structural reinforcement that compensates for the reduced thickness, enabling thin protective layers that still possess adequate mechanical strength and defect resistance while maximizing ion conductivity.
Solution Approach 2:
The inorganic ion-conducting material is selectively placed within the pores of the polymer separator, creating local regions of high ion conductivity. This localized enhancement of ion transport properties allows the protective layer to be thin overall while maintaining sufficient ion conductivity through the pore-filled regions, without requiring the entire layer to be thick for mechanical strength.
3Reliability
If inorganic ion conductor layer is made thinner to reduce resistance, then ion conductivity improves, but adhesion and mechanical stability worsen
Solution Approach 1:
The porous polymer separator serves as a scaffold that provides mechanical support and adhesion for the thin inorganic ion-conducting layer. The inorganic material fills the pores and adheres to the polymer matrix, creating a mechanically stable composite. This porous support structure allows the inorganic layer to be thin for low resistance while the polymer matrix provides the necessary adhesion and mechanical stability.
Solution Approach 2:
The composite structure of porous polymer and inorganic material creates a synergistic relationship where the polymer provides mechanical stability and adhesion, while the inorganic material provides high ion conductivity. The combination allows the inorganic layer to be thin without compromising adhesion, as the polymer matrix anchors the inorganic material throughout the structure.
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 configuration reduces the likelihood of delamination and mechanical failure, maintaining the integrity of the protective structure and preventing electrolyte degradation of the electroactive material, even under mechanical stress and swelling conditions.
Implementation Method 1
an inorganic ion conductor layer bonded to the separator... wherein the inorganic ion conductor layer has an ion conductivity of at least 10^-7 S/cm
Implementation Method 2
the ion-conducting material may be in the form of a plurality of vias of ion-conducting material at least partially surrounded by a separator matrix
Data Source
AI summary
The use of ion-conducting materials to protect electrodes is generally described. The ion-conducting material may be in the form of a layer that is adjacent to a polymeric layer, such as a porous separator, to form a composite. At least a portion of the pores of the polymer layer may be filled or unfilled with the ion-conducting material. In some embodiments, the ion-conducting layer is sufficiently bonded to the polymer layer to prevent delamination of the layers during cycling of an electrochemical cell.