Composite Semi-Solid Electrolyte for Dendrite-Resistant Batteries
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Solution Overview
Problem
Solid state electrolyte batteries face issues such as interface reactions with lithium metal anodes, potential lithium dendrite formation, and inadequate electrolyte infiltration, leading to reduced performance and cycle life.
Innovation Solution
A semi-solid state electrolyte composite is developed, comprising a support with layers of lithium-containing salts like LiPO3 and PEO, which is wet with a lithium-containing salt and organic solvent, enhancing ionic conductivity and reducing lithium dendrite growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solid state electrolyte is used, then battery safety is improved, but interface reactions with lithium metal anode occur forming resistive layers
Solution Approach 1:
The patent uses a composite electrolyte consisting of solid PEO matrix combined with liquid electrolyte components (LiPF6 salt and carbonate solvents). This composite structure combines the safety benefits of solid electrolytes with the high ionic conductivity and lithium compatibility of liquid electrolytes, preventing interface reactions while maintaining safety improvements.
Solution Approach 2:
The patent changes the physical state parameter of the electrolyte from purely solid to semi-solid by incorporating liquid components. This parameter change allows the electrolyte to maintain the structural integrity and safety of solid electrolytes while gaining the chemical compatibility and ionic conductivity characteristics of liquid electrolytes.
2Stability of the object's composition
If crystal or glassy SSE is used, then electrolyte stability is improved, but anode and cathode materials are damaged due to hardness mismatch
Solution Approach 1:
The patent creates a composite electrolyte system where the solid PEO matrix provides stability while the liquid electrolyte components provide softness and compatibility with electrode materials. This composite approach allows the electrolyte to maintain its stable composition while avoiding mechanical damage to softer anode and cathode materials.
Solution Approach 2:
The patent applies different properties to different parts of the electrolyte system: the PEO matrix provides structural stability and mechanical strength, while the liquid electrolyte components localized at the electrode interfaces provide softness and chemical compatibility. This local differentiation of properties resolves the contradiction between stability and mechanical compatibility.
3Reliability
If solid electrolyte is used, then battery safety is improved, but lithium dendrite deposition occurs at the interface
Solution Approach 1:
The composite semi-solid electrolyte combines the safety advantages of solid electrolytes with the lithium-ion compatibility of liquid electrolytes. The liquid components (LiPF6 and carbonate solvents) create a stable solid electrolyte interface (SEI) that prevents lithium dendrite formation, while the solid PEO matrix maintains structural integrity and safety.
Solution Approach 2:
The liquid electrolyte components act as an intermediary between the solid PEO matrix and the lithium metal anode. This intermediary layer facilitates smooth lithium-ion transport and prevents direct harmful interactions that would lead to dendrite formation, while the solid matrix provides the safety benefits.
4Ease of operation
If liquid electrolyte is used, then electrolyte infiltration is improved, but battery safety is reduced compared to solid electrolyte
Solution Approach 1:
The patent creates a composite electrolyte that combines liquid and solid components. The liquid electrolyte portion infiltrates the battery cell effectively like traditional liquid electrolytes, while the solid PEO matrix provides the safety benefits. This composite structure allows both infiltration and safety to coexist.
Solution Approach 2:
The patent changes the physical state parameter from purely liquid to semi-solid, creating a hybrid state that retains the infiltration capabilities of liquid electrolytes while incorporating the safety characteristics of solid electrolytes. This parameter transition resolves the contradiction between infiltration ease and safety.
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 achieves improved cycle life and capacity retention, with over 80% charge capacity maintained after 250 cycles and reduced lithium deposition, leading to enhanced battery performance and safety.
Implementation Method 1
At least a portion of the composite may be wet with liquid electrolyte to form the semi-solid state electrolyte
Implementation Method 2
The layer may include a mixture of LiPO3 and PEO... enhancing ionic conductivity
Data Source
AI summary
2. A composite for forming an improved semi-solid state electrolyte. The composite has a layer formed including lithium metaphosphate (LiPO3). The layer may include a mixture of LiPO3 and PEO. The composite may be wet with liquid electrolyte to form the semi-solid state electrolyte. When used in a semi-solid state battery, the semi-solid state electrolyte provides beneficial results, including improved cycle life and less lithium dendrite growth. Another composite for forming an improved semi-solid state electrolyte has a layer formed including LiTaO3 and LiNbO3. Yet another composite has a single layer formed to include a mixture of a polyethylene oxide and a lithium-containing salt, including a lithium salt including niobium, tantalum, or mixtures thereof. Such composites may be wet with liquid electrolyte to form the semi-solid state electrolyte. When used in a semi-solid state battery, the semi-solid state electrolyte provides beneficial results, including improved cycle life and less lithium dendrite growth.