Fiber-Reinforced Solid Electrolyte for Lithium Dendrite Resistance
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Solution Overview
Problem
Lithium metal batteries face premature failure due to lithium dendrite growth, which penetrates the separator and causes internal short circuits, as existing solid state electrolytes have low fracture toughness and are prone to cracking, compromising their ability to resist dendrite penetration.
Innovation Solution
Reinforcing the solid electrolyte with fibers to enhance fracture toughness while maintaining ionic conductivity, using a combination of glass formers, modifiers, and dopants in sulfide or oxy-sulfide glass compositions, and incorporating thermoplastic polymers with suitable glass transition temperatures to create a fiber-reinforced separator/solid electrolyte that prevents dendrite penetration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If solid state electrolytes are used to suppress lithium dendrite penetration, then reliability is improved, but fracture toughness is low causing cracking and premature failure
Solution Approach 1:
The patent applies composite materials by combining glass ceramic matrix with crystalline phases and fiber reinforcements to create a multi-phase solid electrolyte. The glass ceramic provides the base structure with ion conductivity, while embedded crystalline phases (such as Li1.3Al0.3Ti0.3O2.64) and fibers enhance fracture toughness and mechanical strength, preventing crack propagation during dendrite penetration attempts.
Solution Approach 2:
The patent employs parameter changes by controlling the composition ratios of glass formers, modifiers, and dopants in the solid electrolyte. By adjusting the chemical composition parameters (such as Li2O-SiO2-P2O5 system ratios) and processing parameters (sintering temperature, atmosphere), the patent optimizes both the ion conductivity and mechanical properties to achieve improved fracture toughness while maintaining dendrite resistance.
2Strength
If fiber reinforcement is added to improve fracture toughness, then strength is improved, but ionic conductivity may be degraded
Solution Approach 1:
The patent applies local quality by strategically positioning fiber reinforcements and crystalline phases within the glass ceramic matrix. The fibers are distributed to provide mechanical reinforcement at critical stress points while maintaining sufficient continuous pathways for lithium ion transport. The local composition is optimized so that reinforcement elements do not completely block ion conduction channels.
Solution Approach 2:
The patent utilizes porous materials by incorporating a controlled porosity structure in the glass ceramic matrix that accommodates fiber reinforcements while maintaining ion transport pathways. The porous structure allows lithium ions to navigate around fiber obstacles, preserving ionic conductivity while the fibers provide mechanical strength and fracture resistance.
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 fiber-reinforced separator/solid electrolyte effectively inhibits dendrite growth and internal short circuits, improving the durability and performance of lithium or sodium ion batteries by maintaining ionic conductivity and preventing complete fracture, thus extending the battery's life and energy density.
Implementation Method 1
The solid, glassy electrolyte serves as both as an ionic conductor (for lithium or sodium ions as appropriate to the anode chemistry)
Implementation Method 2
reinforcing the separator/solid electrolyte with fibers at a concentration sufficient to improve the fracture toughness of the separator/solid electrolyte
Implementation Method 3
other chemical combinations, including complex hydride compositions such as LiBH4.LiNH2, which forms an ion-conducting crystalline or ceramic phase
Data Source
AI summary
Fiber-reinforced separators/solid electrolytes suitable for use in a cell employing an anode comprising an alkali metal are disclosed. Such fiber-reinforced separators/solid electrolytes may be at least partially amorphous and prepared by compacting, at elevated temperatures, powders of an ion-conducting composition appropriate to the anode alkali metal. The separators/solid electrolytes may employ discrete high aspect ratio fibers and fiber mats or plate-like mineral particles to reinforce the separator solid electrolyte. The reinforcing fibers may be inorganic, such as silica-based glass, or organic, such as a thermoplastic. In the case of thermoplastic fiber-reinforced separators/solid electrolytes, any of a wide range of thermoplastic compositions may be selected provided the glass transition temperature of the polymer reinforcement composition is selected to be higher than the glass transition temperature of the amorphous portion of the separator/solid electrolyte.