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Insights into the role of silicon and graphite in the electrochemical performance of silicon/graphite blended electrodes with a multi-material porous electrode model

journal contribution
posted on 14.03.2022, 12:04 by Yang Jiang, Zhiqiang Niu, Gregory Offer, Jin XuanJin Xuan, Huizhi Wang
Silicon/graphite blended electrodes are promising candidates to replace graphite in lithium ion batteries, benefiting from the high capacity of silicon and the good structural stability of carbon. Models have proven essential to understand and optimise batteries with new materials. However, most previous models treat silicon/graphite blends as a single "lumped"material, offering limited understanding of the behaviors of the individual materials and thus limited design capability. Here, we present a multi-material model for silicon/graphite electrodes with detailed descriptions of the contributions of the individual active materials. The model shows that silicon introduces voltage hysteresis to silicon/graphite electrodes and consequently a "plateau shift"during delithiation of the electrodes. There will also be competition between the silicon and graphite lithiation reactions depending on silicon/graphite ratio. A dimensionless competing factor is derived to quantify the competition between the two active materials. This is demonstrated to be a useful indicator for active operating regions for each material and we demonstrate how it can be used to design cycling protocols for mitigating electrode degradation. The multi-material electrode model can be readily implemented into full-cell models and coupled with other physics to guide further development of lithium ion batteries with silicon-based electrodes.

Funding

Smart Microfluidics Towards Low-Cost High-Performance Li-Ion Batteries

Engineering and Physical Sciences Research Council

Find out more...

Innovate UK WIZer project (TS/S005811/1)

Faraday Institution Multiscale Modeling project (EP/S003053/1, FIRG003)

Royal Society-K C Wong Education Foundation International Fellowship NIF\R1\191864

History

School

  • Aeronautical, Automotive, Chemical and Materials Engineering

Department

  • Chemical Engineering

Published in

Journal of The Electrochemical Society

Volume

169

Issue

2

Publisher

IOP Publishing

Version

AM (Accepted Manuscript)

Rights holder

© The Electrochemical Society (“ECS”)

Publisher statement

This is the Accepted Manuscript version of an article accepted for publication in Journal of The Electrochemical Society. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at https://doi.org/10.1149/1945-7111/ac5481

Publication date

2022-02-23

Copyright date

2022

ISSN

0013-4651

eISSN

1945-7111

Language

en

Depositor

Prof Jin Xuan. Deposit date: 13 March 2022

Article number

020568