Gradient-Porous Solid Electrolyte for Dendrite-Resistant Li Batteries
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Solution Overview
Problem
Lithium secondary batteries with inorganic solid electrolytes face issues of lithium penetration into grain boundaries, leading to short circuits and increased interfacial resistance due to lithium metal electrodes, which limits their capacity and stability.
Innovation Solution
A solid electrolyte with a porous layer structure is developed, featuring a gradient in pore size and porosity, where the surface has larger pores than the interior, reducing lithium penetration and enhancing ionic conductivity and mechanical strength, thereby minimizing interfacial resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If an inorganic solid electrolyte is used as an electrolyte in a lithium secondary battery including a lithium metal electrode, then the battery voltage and charge storage capacity can be increased, but lithium penetration into grain boundaries occurs causing short circuits and increased interfacial resistance
Solution Approach 1:
The patent applies a porous coating layer on the inorganic solid electrolyte surface. This porous structure increases the surface area for lithium ion insertion/extraction, reduces interfacial resistance, and prevents direct contact between lithium metal and grain boundaries, thereby avoiding short circuits while maintaining high voltage and capacity.
Solution Approach 2:
The patent creates a composite structure by combining the inorganic solid electrolyte with a porous coating material. This composite approach leverages the high ionic conductivity of the inorganic electrolyte while the porous coating provides mechanical protection and prevents lithium penetration, resolving the contradiction between performance and reliability.
2Ease of manufacture
If the porous layer has uniform pore size throughout, then the structure is simple to manufacture, but it cannot effectively inhibit lithium dendrite formation at the interface with the inorganic electrolyte
Solution Approach 1:
The patent implements a gradient pore size distribution within the porous layer, with smaller pores at the interface with the inorganic electrolyte and larger pores toward the exterior. This local variation optimizes lithium ion transport at each interface, effectively inhibiting dendrite formation at the critical inorganic electrolyte interface while maintaining manufacturability.
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 layer structure increases the contact area with electrodes, inhibits lithium dendrite formation, and maintains battery capacity and stability over multiple cycles, improving the overall performance of lithium secondary batteries.
Implementation Method 1
a porous layer, and a first porous layer on the surface of the second porous layer, wherein a pore size of the first porous layer is greater than a pore size of the second porous layer
Implementation Method 2
The method includes acid-treating the inorganic lithium ion conductive film by applying an acid having a concentration of greater than or equal to 0.1 M and less than 5 M thereto; and cleaning an acid-treated product
Data Source
Figure 1~2
Figure 3
Figure 4A
AI summary
A solid electrolyte including an inorganic lithium ion conductive film and a porous layer on a surface of the inorganic lithium ion conductive film, wherein the porous layer includes a first porous layer and a second porous layer, and the second porous layer is disposed between the inorganic lithium ion conductive film and the first porous layer, and wherein the first porous layer has a size greater which is than a pore size of the second porous layer.