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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 contributionposted on 14.03.2022, 12:04 authored by Yang Jiang, Zhiqiang NiuZhiqiang Niu, Gregory Offer, Jin 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.
Smart Microfluidics Towards Low-Cost High-Performance Li-Ion Batteries
Engineering and Physical Sciences Research CouncilFind 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
- Aeronautical, Automotive, Chemical and Materials Engineering
- Chemical Engineering