Thick Electrodes with Vertical Channels for Li-Ion Transport
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Solution Overview
Problem
Conventional Li-ion battery electrodes, when made thin to meet automotive power requirements, compromise energy density due to increased weight and volume of inactive components, and thick electrodes face challenges with Li-ion transport and electrochemical reaction homogeneity, leading to capacity fading and compromised rate capability.
Innovation Solution
The development of thick electrodes with controlled vertical channels to enhance Li-ion transport, achieved through a combination of binder chemistry, solid loading, dispersant use, carbon network optimization, and controlled drying processes, which improves electrolyte access and electrode stability, allowing for higher rate capability and homogeneous reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If electrode thickness is increased to improve energy density, then active material utilization ratio improves, but Li-ion transport becomes limited and electrochemical reaction homogeneity deteriorates
Solution Approach 1:
The electrode is segmented into multiple functional layers including a porous support layer with interconnected pores and an active material layer. This segmentation allows Li-ion transport pathways to be divided and distributed throughout the electrode thickness, enabling thick electrodes to maintain homogeneous electrochemical reactions by providing multiple parallel transport routes that reduce local congestion and improve reaction uniformity across the entire electrode volume.
2Quantity of substance
If electrode thickness is increased to improve energy density, then active material utilization ratio improves, but rate capability is compromised
Solution Approach 1:
The electrode structure implements local quality optimization by creating a porous support layer with specific pore size distributions and connectivity patterns tailored for fast Li-ion transport. The pore structure is designed with optimized tortuosity and diameter in different regions to facilitate rapid ion diffusion, while the active material is strategically distributed within this porous framework. This local structural optimization enables thick electrodes to achieve both high energy density and superior rate capability by ensuring efficient ion transport pathways are present throughout the entire electrode thickness.
3Power
If thin electrodes are used to meet power requirements, then power delivery is improved, but energy density is compromised due to increased weight and volume of inactive components
Solution Approach 1:
The invention transitions from conventional 2D planar electrode structures to a 3D porous architecture with vertical and lateral interconnected pathways. This dimensional change allows the electrode to effectively utilize the third dimension (thickness) for active material placement while maintaining short ion transport distances through the porous network. The 3D structure enables thick electrodes to deliver high power performance comparable to thin electrodes while significantly increasing energy density by maximizing active material content without proportionally increasing inactive component weight and volume.
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
The approach results in improved energy and power densities, with electrodes exhibiting enhanced rate capability and stability, maintaining performance across a wide range of C-rates while minimizing capacity degradation.
Implementation Method 1
vertical channels can be produced that run through the entire thickness of the electrode. As the thickness of the electrode increases, these channels form a pathway for fast ionic transport
Implementation Method 2
tertiary butanol can be used as an additive in the electrode slurry. This reduces the surface tension of the slurry and decreases the volatility of the solvent
Implementation Method 3
drying temperature and time can be used to control the channel size and density
Data Source
AI summary
Disclosed herein are electrodes for electrochemical devices and methods of making the electrodes. The electrodes include an electrode body comprising a plurality of channels wherein at least a portion of the channels extend from the first surface to the second surface of the electrode body. In the methods of making the electrodes, a combination of binder chemistry, solid loading, dispersant, types of carbon network, substrate surface modification, and drying temperature and time can be used to control the channel size and density.