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In Situ TEM Investigation of Electrolyte Penetration and SEI Formation of Nanoporous Silicon Battery Anode Materials


EMSL Project ID
49653

Abstract

Due to the high theoretical capacity of silicon, silicon nanomaterial anodes have been investigated by our group as advanced active materials for lithium-ion battery anodes, but are limited by their high volumetric expansion and by parasitic side reactions with electrolytes.
To address these concerns, we have developed nanoporous silicon structures on larger length scales. The pores allow for volume expansion with decreased damage to the anode, while the larger size decreases surface area available for electrolyte penetration.
We have found that coating these structures with hydrophobic surface layers dramatically improves the coulombic efficiency, and hypothesize that this is due to the hydrophobic layer reducing or preventing electrolyte penetration into the anode while cycling.
We are requesting rapid access time to confirm this hypothesis for rapid publication in a quickly-moving field, via electrochemical in situ wetting experiments. Furthermore, we would like to investigate the feasibility of longer term, challenging experiments towards a full proposal. These include the use of XEDS STEM tomography and liquid cell in situ mass spectrometry available at EMSL to investigate the mechanism of formation and chemical evolution of the SEI layer in situ, both within the pores and on the surface of the coated structures.

Project Details

Project type
Limited Scope
Start Date
2016-10-18
End Date
2016-12-18
Status
Closed

Team

Principal Investigator

Yi Cui
Institution
Stanford University

Team Members

HyeRyoung Lee
Institution
Stanford University

Shilpa Raja
Institution
Stanford University