Abstract
In this work, we explore how the chemical reactivity toward an aprotic battery electrolyte changes as a function of lithium salt and silicon surface termination chemistry. The reactions are highly correlated, where one decomposition reaction leads to a subsequent decomposition reaction. The data show that the presence of silicon hydrides (SiHx) promotes the formation of CO gas, while surface oxides SiOx drive the formation of CO2. The extent and rate of oxidation depend on the surface basicity of the SiO2 surface species. The most acidic surfaces seem to hinder CO2 generation but not the decomposition of the salt. Indeed, the presence of F-containing salts (LiPF6 and LiTFSI) promotes the reactions between carbonate electrolyte and silicon surfaces. Surfaces with high Li content seem to be the most passivating to gassing reactions, pointing to a pathway to stabilize the interfaces during cell formation and assembly.
| Original language | English |
|---|---|
| Pages (from-to) | 3199-3210 |
| Number of pages | 12 |
| Journal | Chemistry of Materials |
| Volume | 32 |
| Issue number | 7 |
| DOIs | |
| State | Published - Apr 14 2020 |
Funding
This research was supported by the U.S. Department of Energy’s Vehicle Technologies Office under the Silicon Electrolyte Interface Stabilization (SEISta) Consortium directed by Brian Cunningham and managed by Anthony Burrell. This manuscript has been authored by team members, which are part of UT-Battelle, LLC, under contract DE-AC05-00OR22725 with the U.S. Department of Energy (DOE), and part of the Alliance for Sustainable Energy, LLC, the manager and operator of the National Renewable Energy Laboratory for the U.S. DOE under Contract No. DE-AC36-08GO28308. The views expressed in the article do not necessarily represent the views of the DOE or the U.S. Government.