First-Principles Analysis of Defect Thermodynamics and Ion Transport in Inorganic SEI Compounds: LiF and NaF
Journal Article
·
· ACS Applied Materials and Interfaces
- Purdue Univ., West Lafayette, IN (United States)
- Argonne National Lab. (ANL), Argonne, IL (United States)
The formation mechanism and composition of the solid electrolyte interphase (SEI) in lithium ion batteries has been widely explored. However, relatively little is known about the function of the SEI as a transport medium. Such critical information is directly relevant to battery rate performance, power loss, and capacity fading. To partially bridge this gap in the case of inorganic SEI compounds, we report herein the results of first-principles calculations on the defect thermodynamics, the dominant diffusion carriers, and the diffusion pathways associated with crystalline LiF and NaF, which are stable components of the SEI in Li-ion and Na-ion batteries, respectively. The thermodynamics of common point defects are computed, and the dominant diffusion carriers are determined over a voltage range of 0–4 V, corresponding to conditions relevant to both anode and cathode SEI’s. Our analyses reveal that for both compounds, vacancy defects are energetically more favorable, therefore form more readily than interstitials, due to the close-packed nature of the crystal structures. However, the vacancy concentrations are very small for the diffusion processes facilitated by defects. Ionic conductivities are calculated as a function of voltage, considering the diffusion carrier concentration and the diffusion barriers as determined by nudged elastic band calculations. These conductivities are more than ten orders of magnitude smaller in NaF than in LiF. As compared to the diffusivity of Li in other common inorganic SEI compounds, such as Li2CO3 and Li2O, the cation diffusivity in LiF and NaF is quite low, with at least three orders of magnitude lower ionic conductivities. Furthermore, the results quantify the extent to which fluorides pose rate limitations in Li and Na batteries.
- Research Organization:
- Energy Frontier Research Centers (EFRC) (United States). Center for Electrical Energy Storage (CEES)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
- Grant/Contract Number:
- AC02-06CH11357
- OSTI ID:
- 1370674
- Alternate ID(s):
- OSTI ID: 1392370
- Journal Information:
- ACS Applied Materials and Interfaces, Journal Name: ACS Applied Materials and Interfaces Journal Issue: 34 Vol. 7; ISSN 1944-8244
- Publisher:
- American Chemical Society (ACS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Similar Records
First-Principles Analysis of Defect Thermodynamics and Ion Transport in Inorganic SEI Compounds: LiF and NaF
Computer analysis of phase diagrams and thermodynamic properties of cryolite based systems: 1. The AlF/sub 3/-LiF-NaF system
Computational Exploration of the Li-Electrode|Electrolyte Interface in the Presence of a Nanometer Thick Solid-Electrolyte Interphase Layer [Computational exploration of the Li-electrode|electrolyte interface complicated by a nanometer thin solid-electrolyte interphase (SEI) layer]
Journal Article
·
Wed Aug 19 00:00:00 EDT 2015
· ACS Applied Materials and Interfaces
·
OSTI ID:1392370
Computer analysis of phase diagrams and thermodynamic properties of cryolite based systems: 1. The AlF/sub 3/-LiF-NaF system
Journal Article
·
Mon Sep 01 00:00:00 EDT 1980
· Metall. Trans., B; (United States)
·
OSTI ID:6000894
Computational Exploration of the Li-Electrode|Electrolyte Interface in the Presence of a Nanometer Thick Solid-Electrolyte Interphase Layer [Computational exploration of the Li-electrode|electrolyte interface complicated by a nanometer thin solid-electrolyte interphase (SEI) layer]
Journal Article
·
Thu Sep 29 20:00:00 EDT 2016
· Accounts of Chemical Research
·
OSTI ID:1338679