Low Tortuosity Electrodes for High Energy Density Batteries
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Solution Overview
Problem
Conventional electrode manufacturing processes result in electrodes with high tortuosity pores, which hinder ion transport and lead to reduced battery performance, requiring thinner electrodes or increased porosity to compensate, thereby decreasing energy density.
Innovation Solution
The development of electrodes with low-tortuosity pores achieved by creating a structure with a matrix material and a fugitive constituent, where the fugitive constituent is removed to form elongated pores, allowing for controlled porosity and higher energy density while maintaining a high volume fraction of active material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If pressure-consolidation is used to achieve high volumetric packing of active material, then energy density is improved, but pore tortuosity increases and ion transport is hindered
Solution Approach 1:
The electrode structure is segmented into distinct regions: a matrix material containing active material particles and a separate aligned porous structure. This segmentation allows the matrix to provide high active material packing while the aligned porous structure provides low-tortuosity ion transport pathways, resolving the contradiction between volumetric packing and pore tortuosity.
Solution Approach 2:
The electrode is constructed as a composite material system combining the matrix material (providing active material packing) with an aligned porous structure (providing low-tortuosity pores). This composite approach enables simultaneous achievement of high volumetric packing and low pore tortuosity, as each component performs its specialized function without compromising the other.
2Ease of manufacture
If conventional electrode fabrication processes are used to accommodate powder active materials, then manufacturing cost is reduced, but pore tortuosity increases and battery performance decreases
Solution Approach 1:
The aligned porous structure is incorporated into the electrode during the fabrication process itself, rather than requiring post-processing modifications. The porous structure is formed simultaneously with the electrode matrix through controlled deposition or assembly, enabling low-tortuosity pore formation as an integral part of manufacturing rather than a subsequent addition.
3Object-generated harmful factors
If thinner electrodes or increased porosity are used to compensate for high tortuosity, then ion transport is improved, but energy density decreases
Solution Approach 1:
The electrode structure implements local quality differentiation: the matrix regions maintain high active material concentration for energy density, while the aligned porous structure provides localized low-tortuosity pathways for efficient ion transport. This spatial differentiation of properties allows the electrode to achieve both high energy density and good ion transport without requiring overall thinning or increased bulk porosity.
Data Source
AI summary
Porous electrodes in which the porosity has a low tortuosity are generally provided. In some embodiments, the porous electrodes can be designed to be filled with electrolyte and used in batteries, and can include low tortuosity in the primary direction of ion transport during charge and discharge of the battery. In some embodiments, the electrodes can have a high volume fraction of electrode active material (i.e., low porosity). The attributes outlined above can allow the electrodes to be fabricated with a higher energy density, higher capacity per unit area of electrode (mAh/cm2), and greater thickness than comparable electrodes while still providing high utilization of the active material in the battery during use. Accordingly, the electrodes can be used to produce batteries with high energy densities, high power, or both compared to batteries using electrodes of conventional design with relatively highly tortuous pores.