Ultrasonic Bonding for Stable Lithium Anode Interfaces
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Solution Overview
Problem
Forming a stable and uniform interface between lithium metal and a solid electrolyte layer in all-solid-state batteries is challenging, especially with sulfide-based electrolytes, due to chemical reactions and difficulties in uniform bonding, which affects the battery's efficiency and durability.
Innovation Solution
A method involving the preparation of a solid electrolyte layer, attachment of a cathode, and the application of ultrasonic waves or sound waves to the stack of lithium metal and solid electrolyte, which helps in forming a uniform interface by aligning non-uniform parts and improving the bonding between the lithium metal and the solid electrolyte layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If lithium metal is used as an anode to achieve high energy density, then capacity per weight and capacity per volume are improved, but chemical reaction with liquid electrolyte occurs making it difficult to use
Solution Approach 1:
A solid electrolyte layer is introduced as an intermediary between the lithium metal anode and the liquid electrolyte. This solid electrolyte layer acts as a protective barrier that prevents direct contact and chemical reaction between lithium metal and liquid electrolyte, while still allowing ionic conduction. The layer is applied in a molten state and then solidified to form a stable interface with the lithium metal.
2Reliability
If solid electrolyte layer is applied to lithium metal, then chemical reaction is prevented, but uniform bonding and stable interface formation is difficult
Solution Approach 1:
The application process utilizes temperature as a critical parameter. The solid electrolyte layer is applied in a molten state at elevated temperature, allowing it to flow and conform uniformly to the lithium metal surface. As the layer cools and solidifies, it forms a stable, uniform bond with the lithium metal, creating a consistent interface structure.
Solution Approach 2:
Ultrasonic vibration is applied during the solidification process to enhance uniform bonding between the solid electrolyte layer and lithium metal. The ultrasonic waves remove non-uniform parts and promote intimate contact at the interface, ensuring a stable and uniform bond without requiring additional sealing steps.
3Strength
If conventional heating and pressurizing method is used to bond solid electrolyte, then bonding is achieved, but non-uniform interface and dendrite formation occur
Solution Approach 1:
Ultrasonic vibration is introduced as an additional bonding mechanism alongside heating and pressurizing. The ultrasonic waves generate mechanical energy that removes non-uniform parts at the interface and promotes uniform contact between the solid electrolyte layer and lithium metal. This prevents dendrite formation by ensuring a consistent interface structure while maintaining strong bonding.
4Manufacturing precision
If ultrasonic waves are radiated to align non-uniform parts, then interface uniformity is improved, but process complexity increases
Solution Approach 1:
The ultrasonic vibration step is merged with the existing heating and pressurizing process. The ultrasonic generator is integrated into the sealing apparatus, allowing simultaneous application of heat, pressure, and ultrasonic vibration during a single operation. This combines multiple functions into one process step, reducing overall process complexity despite adding ultrasonic capability.
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 method enables the formation of a stable and uniform interface, enhancing the charging and discharging efficiency, preventing dendrite formation, and increasing the volume and weight energy density of the battery, while allowing for the manufacture of large-area batteries with improved durability and reduced costs.
Implementation Method 1
radiating ultrasonic waves or sound waves to the stack
Implementation Method 2
forming a uniform interface by aligning non-uniform parts
Implementation Method 3
improving the bonding between the lithium metal and the solid electrolyte layer
Data Source
AI summary
A method of manufacturing an all-solid-state battery includes preparing a solid electrolyte layer, providing lithium metal to the solid electrolyte layer to prepare a stack, and radiating ultrasonic waves or sound waves to the stack. The method provides an all-solid-state battery with a stable interface between an anode formed of lithium metal and a solid electrolyte layer.