Indented Electrode Particles for Porous Support Structure
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Solution Overview
Problem
Existing electrochemical cells face challenges in maintaining sufficient void volume within electrodes, which is crucial for electrolyte access to electrode active material, especially under applied forces that can reduce porosity and degrade performance.
Innovation Solution
The use of particles with indentations relative to their convex hulls forms a porous support structure, ensuring that at least 50% of the total geometric particle volume is made up of particles with indentations, thereby maintaining void volume and preventing complete contact between particles, allowing for the application of forces without sacrificing structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If particles are packed densely to increase energy density, then the volume occupancy of particulate material increases, but the void volume within the electrode decreases, reducing electrolyte access and performance
Solution Approach 1:
The patent employs particles with inherent porous structures and indentations that create internal void spaces. These porous particles maintain electrode porosity even at high packing densities, allowing electrolyte penetration while achieving high energy density. The indentations on particle surfaces create additional interparticle void volume when particles are assembled, resolving the contradiction between dense packing and electrolyte access.
2Strength
If applied forces are used to compress the electrode to improve structural integrity, then the mechanical strength increases, but the porosity and void volume decrease, degrading electrochemical performance
Solution Approach 1:
The patent incorporates void volume and porous structures into the electrode design before any compressive forces are applied during operation. The indentations on particles create built-in cushioning spaces that can accommodate compression forces without collapsing the overall porosity. This beforehand cushioning allows the electrode to withstand mechanical stresses while maintaining the porosity needed for electrochemical performance.
3Volume of stationary object
If particles with indentations are used to maintain void volume, then the porosity is preserved, but the geometric particle volume increases relative to spherical particles
Solution Approach 1:
The patent utilizes asymmetric particle shapes with indentations rather than symmetric spherical particles. These asymmetric shapes with strategically placed indentations create more efficient packing arrangements that generate interparticle voids. The asymmetric geometry allows particles to nestle together in ways that maximize void volume while minimizing the total geometric particle volume, effectively resolving the contradiction between maintaining porosity and reducing material volume.
Data Source
AI summary
Electrode structures and methods for making the same are generally described. In certain embodiments, the electrode structures can include a plurality of particles, wherein the particles comprise indentations relative to their convex hulls. As the particles are moved proximate to or in contact with one another, the indentations of the particles can define pores between the particles. In addition, when particles comprising indentations relative to their convex hulls are moved relative to each other, the presence of the indentations can ensure that complete contact does not result between the particles (i.e., that there remains some space between the particles) and that void volume is maintained within the bulk of the assembly. Accordingly, electrodes comprising particles with indentations relative to their convex hulls can be configured to withstand the application of a force to the electrode while substantially maintaining electrode void volume (and, therefore, performance). Particles having indentations relative to their convex hulls also occupy a relatively small volume, compared to spheres or other particles including boundaries that fill substantially all of their convex hulls, allowing one to introduce a desired amount of void volume while reducing the percentage of volume within the electrode occupied by particulate material.