Revisiting the promise of bi-layer graded cathodes for improved Li-ion battery performance
File(s)d1se01077h.pdf (1.31 MB)
Published version
Author(s)
Type
Journal Article
Abstract
Improving power and energy density by grading electrode microstructures is a promising topic in the field of battery electrode engineering. While previous modelling studies have predicted both considerable and marginal improvements in cell performance, very few experimental studies have been conducted to validate the performance of graded electrodes. In this article, we report on the fabrication of a bi-layer graded lithium-ion battery cathode by varying both the particle size and the porosity in each layer. Structural analyses were carried out via 2D (scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX)) and 3D (X-ray computed tomography (XCT) and focused-ion beam tomography (FIB)) imaging techniques. The bi-layer cathode (BLC) exhibits an increase of 62.8% in discharge capacity at 2C compared to a conventional single layer electrode. The polarization and electrochemical impedance spectroscopy data indicate that the improved capacity performance of the BLC can be attributed to reduced charge transfer resistance and increased solid phase diffusivity. However, capacity retention performance reveals that the BLC retained no advantage over a conventional electrode in a half-cell configuration after 100 cycles. At 1C, the BLC displayed only minimal improvement in power (4.6%) and energy (7.6%) density based on first discharge capacity. As such, noting the extra challenges involved in manufacturing such graded electrode structures, it is recommended that their use is best focused on higher C rate applications and that more work is needed to demonstrate the retention of the higher C rate performance gain over multiple cycles.
Date Issued
2021-10-21
Date Acceptance
2021-09-10
Citation
Sustainable Energy and Fuels, 2021, 5 (20), pp.5193-5204
ISSN
2398-4902
Publisher
Royal Society of Chemistry
Start Page
5193
End Page
5204
Journal / Book Title
Sustainable Energy and Fuels
Volume
5
Issue
20
Copyright Statement
© The Royal Society of Chemistry 2021. This article is licensed under a Creative Commons Attribution 3.0 Unported Licence (https://creativecommons.org/licenses/by/3.0/)
License URL
Sponsor
Engineering & Physical Science Research Council (E
Grant Number
DJR00640
Subjects
Science & Technology
Physical Sciences
Technology
Chemistry, Physical
Energy & Fuels
Materials Science, Multidisciplinary
Chemistry
Materials Science
HIGH-ENERGY DENSITY
ELECTROCHEMICAL PROPERTIES
POROSITY DISTRIBUTION
CYCLING PERFORMANCE
DESIGN PARAMETERS
BINDER MIGRATION
LITHIUM
ELECTRODE
THICKNESS
OXIDE
Publication Status
Published
Date Publish Online
2021-09-10