Porous-Dense Garnet Ribbon Structure for Li Dendrite Suppression
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Solution Overview
Problem
Lithium metal dendrite formation and significant volume change of the Li metal anode during cycling pose major challenges in the application of garnet electrolytes in solid-state lithium-ion batteries.
Innovation Solution
A porous-dense bilayer architecture of garnet tapes/ribbons, where a porous garnet layer is deposited on top of a thin dense garnet electrolyte layer, well-sintered at the interface, to inhibit Li-dendrite growth and stabilize the anode volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dense garnet electrolyte layer is used, then Li-ion conductivity is improved, but Li dendrite formation is promoted
Solution Approach 1:
The patent introduces a porous layer within the garnet electrolyte structure. This porous layer provides a physical barrier that prevents Li dendrite penetration while maintaining Li-ion conductivity through the porous network. The porous structure allows ion transport while mechanically blocking dendrite growth, resolving the contradiction between conductivity and dendrite resistance.
Solution Approach 2:
The patent creates a composite garnet electrolyte structure combining dense and porous regions. The dense regions provide high Li-ion conductivity, while the porous regions provide mechanical barrier function against dendrites. This composite architecture allows both functions to coexist, resolving the contradiction between conductivity and dendrite prevention.
2Strength
If a thick garnet electrolyte layer is used, then mechanical strength is improved, but volume change accommodation is worsened
Solution Approach 1:
The porous layer acts as a buffer that can accommodate volume changes of the Li metal anode during cycling. The porous network provides space for expansion and contraction, reducing mechanical stress on the overall structure. This allows the use of thinner electrolyte layers without compromising mechanical integrity, as the porous layer compensates for volume changes.
Solution Approach 2:
The patent segments the garnet electrolyte into multiple functional layers including dense regions for strength and conductivity, and porous regions for volume accommodation. This segmentation allows each layer to specialize in its function, with the dense layers providing mechanical strength and the porous layers providing volume change buffer, resolving the contradiction between strength and volume accommodation.
3Object-affected harmful factors
If a porous garnet layer is added, then Li dendrite formation is prevented, but manufacturing complexity is increased
Solution Approach 1:
The porous structure is incorporated into the green tape before sintering, using pore-forming agents that are removed during the sintering process. This preliminary incorporation of porosity avoids the need for post-processing steps to create pores, simplifying manufacturing. The porosity is built-in from the start, preventing dendrites without adding complex post-manufacturing steps.
Solution Approach 2:
The patent controls porosity parameters (pore size, distribution, density) during the tape casting and sintering processes to optimize both dendrite prevention and manufacturability. By carefully selecting pore-forming agent sizes and sintering conditions, the desired porous structure is achieved through standard ceramic processing techniques, avoiding excessive manufacturing complexity while maintaining effective dendrite prevention.
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 porous-dense bilayer structure provides a continuous conductive route for Li+ ion movement, constrains lithium to prevent cell dimension changes, and reduces local current density to prevent Li dendrite formation, enhancing the stability and performance of solid-state lithium-ion batteries.
Implementation Method 1
the porous network of garnet on the dense electrolyte can not only provide a continuously conductive route for Li+ ion movement
Implementation Method 2
Porosity and pore size in sintered LLZO can be controlled by reaction sintering of precursor materials
Data Source
AI summary
The disclosure relates to porous garnet ribbons and methods of making such porous garnet ribbons.