Garnet Solid Electrolyte Composite for Li Dendrite Suppression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In power storage devices, the growth of metallic Li dendrites can lead to short circuits, particularly when oxide grains with a garnet-type crystal structure are used, as they readily grow through grain boundaries.
Innovation Solution
Incorporating inorganic grains composed of main-group elements, including Mg, with a median diameter smaller than the oxide grains and a specific volume ratio, into the intergranular space of oxide grains with a garnet-type crystal structure to suppress dendritic growth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If oxide grains with garnet-type crystal structure are used as solid electrolyte material, then electrochemical stability and Li ion conductivity are improved, but dendritic growth of metallic Li occurs readily through grain boundaries resulting in short circuit
Solution Approach 1:
The patent introduces inorganic particles (such as Al2O3, SiO2, MgO, or their composite particles) as intermediary substances filling the grain boundaries between oxide grains. These inorganic particles act as mediators that block the direct contact and continuous pathways at grain boundaries, thereby suppressing dendritic growth while maintaining the electrochemical stability of the oxide solid electrolyte material.
Solution Approach 2:
The patent creates a composite structure by combining oxide grains with garnet-type crystal structure and inorganic particles. This composite material approach leverages the electrochemical stability and Li ion conductivity of the oxide grains while utilizing the dendrite-blocking properties of the inorganic particles, achieving both stability and safety through material composition.
2Object-affected harmful factors
If inorganic particles are added to suppress dendritic growth, then safety against short circuit is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent optimizes specific parameters of the inorganic particles including particle size (0.1-10 μm), content (1-50 wt% of total solid electrolyte), and shape (spherical, irregular, or rod-like) to achieve effective dendrite suppression. By controlling these parameters within specific ranges, the patent balances safety improvement with manufacturing feasibility, avoiding excessive complexity.
Solution Approach 2:
The inorganic particles create a controlled porous or discontinuous structure at grain boundaries that physically blocks dendrite pathways. This porous approach provides effective safety protection while maintaining a relatively simple composite structure that can be manufactured using conventional mixing and sintering processes.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
To provide an assembly composite, a sheet, a separator and an electrode in which dendritic growth of metallic Li is suppressed, and a power storage device. The assembly composite (10) which contains oxide grains (19) having a garnet-type crystal structure (22) containing Li, La, and Zr, and inorganic grains composed of a main-group element including Mg. The median diameter of the inorganic grains is 1/2 or less the median diameter of the oxide grains. The volume ratio of the inorganic grains to the oxide grains is 1 vol% or more and 10 vol% or less. The power storage device (11) includes the assembly composite.