Title: Effect of Temperature and FEC on Silicon Anode Heat Generation Measured by Isothermal Microcalorimetry

Abstract

Isothermal microcalorimetry (IMC) was used to better understand parasitic reactions and heat generation from Si electrodes in the first 10 cycles using Li/Si half cells. Heat generation from cell polarization (ohmic heat), entropy changes (reversible heat), and parasitic reactions (parasitic heat) are separated and quantified. The effect of temperature and fluoroethylene carbonate (FEC) as an electrolyte additive are also explored. Our results show that at the C/10 cycling rate used here, ohmic heat makes the largest contribution to overall heat generation while reversible heat is the smallest. Ohmic heat generation increases with cycle number due to increasing internal resistance, though the effect is smaller for cells with FEC. Interestingly, capacity-normalized parasitic heat generation is largely unaffected by changes in temperature despite differing reaction kinetics. We show that this is caused by a decrease in average parasitic reaction enthalpy as temperature is increased. Further, cells with FEC display higher average parasitic reaction enthalpy than cells without. The average parasitic reaction enthalpies for all the Si electrodes we tested were lower than previously reported values for graphite, indicating that the SEI formed on Si is less stable.

Authors:

Arnot, David J.  ^[1];

• Search DOE PAGES for author "Arnot, David J."
• Search DOE PAGES for ORCID "0000-0002-1138-3655"

Allcorn, Eric ^[1]; Harrison, Katharine L. ^[1]

---

+ Show Author Affiliations

1. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

Publication Date:

Tue Nov 09 00:00:00 EST 2021

Research Org.:

Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

Sponsoring Org.:

USDOE Office of Energy Efficiency and Renewable Energy (EERE), Transportation Office. Vehicle Technologies Office

OSTI Identifier:

1830532

Report Number(s):

SAND-2021-14430J
Journal ID: ISSN 0013-4651; 701530

Grant/Contract Number:  

NA0003525

Resource Type:

Accepted Manuscript

Journal Name:

Journal of the Electrochemical Society

Additional Journal Information:

Journal Volume: 168; Journal Issue: 11; Journal ID: ISSN 0013-4651

Publisher:

IOP Publishing - The Electrochemical Society

Country of Publication:

United States

Language:

English

Subject:

25 ENERGY STORAGE