Spalled Cathode Material Layer for High-Capacity Battery Stacks
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Solution Overview
Problem
Conventional rechargeable batteries face challenges in achieving high capacity and performance due to limitations in cathode material thickness, polymeric binder-induced capacity degradation, and the need for large surface areas, which are addressed by employing a spalled material structure with a single crystalline cathode material layer and a stressor material as a current collector.
Innovation Solution
The spalling process is used to create a spalled cathode material layer with a stressor material, which is devoid of polymeric binders and has improved uniformity and lithium transport, allowing for thicker layers and higher capacity batteries, with the stressor material serving as a cathode current collector and the spalling process enabling controlled fracture for enhanced performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional deposition methods are used to create cathode material layers, then the layers can be formed with polymeric binders, but the capacity degradation occurs and uniformity is reduced
Solution Approach 1:
The invention extracts and removes polymeric binders from the cathode material layer by using a spalling process that separates the cathode material from the substrate while leaving behind a binder-free layer. This extraction eliminates the capacity degradation caused by polymeric binders while maintaining layer uniformity through the controlled spalling mechanism.
Solution Approach 2:
Instead of trying to improve conventional deposition methods, the invention inverts the approach by using a spalling process that removes material rather than adding it. This inversion allows creation of binder-free cathode layers with superior uniformity and capacity retention by eliminating the binder removal step that is problematic in conventional methods.
2Quantity of substance
If thicker cathode material layers are used to increase capacity, then higher battery capacity is achieved, but conventional methods cannot produce sufficiently thick uniform layers
Solution Approach 1:
The invention applies preliminary action by depositing a thick cathode material layer onto a substrate with polymeric binder before the spalling process. This preliminary thick layer deposition is made possible because the binder provides temporary structural support, allowing thicknesses that would be impossible to achieve directly in a uniform binder-free state. The subsequent spalling then creates the final thick, uniform binder-free layer.
Solution Approach 2:
The polymeric binder serves as an intermediary that enables the formation of thick cathode layers. During the deposition phase, the binder acts as a mediator that holds the thick layer together and provides structural integrity. After deposition, the binder is removed through spalling, leaving the thick uniform layer without the intermediary, thus achieving both high capacity and uniformity.
3Quantity of substance
If large surface areas are used to achieve high capacity, then battery capacity increases, but device size and complexity increase
Solution Approach 1:
The invention changes the parameter of cathode layer thickness from thin to thick, which fundamentally alters the capacity-to-area ratio. By achieving binder-free thick layers through spalling, the battery can attain high capacity without proportionally increasing surface area, thus reducing device complexity while maintaining high capacity output.
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 rechargeable batteries with capacities greater than 50 mAh/gm and improved performance by overcoming the limitations of conventional deposition methods, providing robust operation and cost-effective high-capacity batteries.
Implementation Method 1
The spalling process is used to create a spalled cathode material layer with a stressor material
Data Source
AI summary
High-capacity (i.e., a capacity of 50 mAh/gm or greater) and high-performance rechargeable batteries are provided that contain a rechargeable battery stack that includes a spalled material structure that includes a cathode material layer that is attached to a stressor material. The cathode material may include a single crystalline that is devoid of polymeric binders. The stressor material serves as a cathode current collector of the rechargeable battery stack.