Solid Electrolyte Grain Orientation for Ion Conductivity
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Solution Overview
Problem
All-solid-state batteries with inorganic solid electrolytes face challenges in lithium ion conductivity due to restricted ion motion in solid electrolytes, particularly in bulk-state configurations where grain boundaries hinder diffusion, leading to low ion conduction rates.
Innovation Solution
A method involving a ceramic-grain sintered body with a crystal plane oriented in a direction intersecting at least one surface of the solid electrolyte, achieved by applying an alternating electric field during the sintering process, enhances ion conduction by aligning the conducting paths, thereby improving charge-and-discharge rate performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a bulk-state solid electrolyte is used, then the battery structure is simple and manufacturing is easier, but the lithium ion conductivity is low due to grain boundaries restricting ion diffusion
Solution Approach 1:
The patent applies local quality by creating a uniaxially pressed solid electrolyte layer where the crystal grains are oriented in a specific direction. This orientation alignment transforms the isotropic grain structure into an anisotropic structure with preferred ion conduction pathways, thereby improving local ion conductivity while maintaining the bulk-state manufacturing approach
Solution Approach 2:
The patent changes the physical parameter of crystal grain orientation through uniaxial pressing during the sintering process. By applying mechanical pressure in a specific direction, the crystal grains are aligned to create preferential pathways for lithium ion diffusion, thereby improving ion conductivity without changing the fundamental bulk-state nature of the electrolyte
2Reliability
If a single crystal film with c-axis orientation is used, then ion conductivity is improved, but the manufacturing cost increases significantly
Solution Approach 1:
The patent uses a disposable uniaxial press applied during the sintering process to achieve crystal grain orientation. This simple mechanical pressing device replaces complex single crystal growth equipment, providing a cost-effective method to achieve improved ion conductivity through grain alignment without requiring expensive single crystal film production techniques
Solution Approach 2:
The patent replaces the complex mechanical and chemical processes required for single crystal film growth with a simpler uniaxial pressing mechanism during sintering. This mechanical substitution achieves crystal grain orientation through straightforward compression, eliminating the need for sophisticated single crystal fabrication equipment and processes
3Manufacturing precision
If magnetic field treatment is applied to control crystal orientation, then some orientation effect is achieved in thin films, but the effect is too small for bulk sintered bodies
Solution Approach 1:
The patent applies uniaxial pressing during the sintering process itself, performing the crystal grain orientation action at the appropriate stage of material formation. This preliminary orientation action during sintering ensures that the crystal grains are aligned before the solid electrolyte layer is finalized, achieving effective grain orientation that magnetic field treatment cannot accomplish in bulk materials
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
This approach results in a solid electrolyte with improved ionic conduction, reducing grain boundary resistance and enhancing the performance of all-solid-state batteries by aligning the ion conducting paths, thus achieving higher energy density and cost-effectiveness.
Implementation Method 1
A method involving a ceramic-grain sintered body with a crystal plane oriented in a direction intersecting at least one surface of the solid electrolyte, achieved by applying an alternating electric field during the sintering process
Implementation Method 2
achieved by applying an alternating electric field during the sintering process
Implementation Method 3
enhances ion conduction by aligning the conducting paths, thereby improving charge-and-discharge rate performance
Data Source
AI summary
According to one embodiment, a solid electrolyte includes a sintered body of ceramic grains. The sintered body includes a crystal plane having an ion conducting path. The crystal plane is oriented in a direction which intersects at least one surface of the solid electrolyte.